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23376 Federal Register / Vol. 74, No. 95 / Tuesday, May 19, 2009 / Proposed Rules
DISPUTES (UTILITY CONTRACTS) materials, comments, or questions provided further information on the
(DATE) concerning this finding to the above species’ status and biology, particularly
The requirements of the Disputes clause at address, Attention: Coaster brook trout. for brook trout in the Salmon Trout
FAR 52.233–1 are supplemented to provide River.
that matters involving the interpretation of FOR FURTHER INFORMATION CONTACT:
Jessica Hogrefe, Region 3 Fish and On September 13, 2007, we received
tariffed retail rates, tariff rate schedules, and
tariffed terms provided under this contract Wildlife Service Regional Office (see a 60-day notice of intent to sue over the
are subject to the jurisdiction and regulation ADDRESSES) (telephone 612–713–5346; Service’s failure to determine, within 1
of the utility rate commission having facsimile 612–713–5292). Persons who year of receiving the petition, whether
jurisdiction. use a telecommunications device for the the coaster brook trout warrants listing.
(End of clause) deaf (TDD) may call the Federal Under section 4 of the Act, the Service
[FR Doc. E9–11654 Filed 5–18–09; 8:45 am] Information Relay Service (FIRS) at is to make a finding, to the maximum
BILLING CODE 6820–61–S 800–877–8339. extent practicable within 90 days of
receiving a petition, that it does or does
SUPPLEMENTARY INFORMATION:
not present substantial scientific or
DEPARTMENT OF THE INTERIOR Background commercial information indicating that
Section 4(b)(3)(B) of the Act (16 the petitioned action may be warranted.
Fish and Wildlife Service U.S.C. 1531 et seq.) requires that, for Further, the Act requires that, within 12
any petition to revise the Lists of months of receiving a petition found to
50 CFR Part 17 Endangered and Threatened Wildlife present substantial information, the
and Plants that contains substantial Service must determine whether the
[FWS–R3–ES–2008–0030; 92210–1111– petitioned action is warranted. A
0000–FY09–B3] scientific and commercial information
that listing may be warranted, we make complaint was filed in U.S. District
Endangered and Threatened Wildlife a finding within 12 months of the date Court in the District of Columbia on
and Plants; 12-Month Finding on a of our receipt of the petition on whether December 17, 2007, for failure to make
Petition To List the Coaster Brook the petitioned action is: (a) Not a timely finding (Sierra Club, et al. v.
Trout as Endangered warranted, (b) warranted, or (c) Kempthorne, No. 1:07–cv–02261 (D.D.C.
warranted, but the immediate proposal December 17, 2007)). The Service
AGENCY: Fish and Wildlife Service, reached a negotiated settlement with the
of a regulation implementing the
Interior. petitioned action is precluded by other plaintiffs to submit the 90-day finding to
ACTION: Notice of 12-month petition pending proposals to determine whether the Federal Register by March 15, 2008.
finding. species are threatened or endangered, We published a ‘‘substantial’’ 90-day
and expeditious progress is being made finding March 20, 2008. The negotiated
SUMMARY: We, the U.S. Fish and settlement further required the Service
to add or remove qualified species from
Wildlife Service (Service), announce a to publish the 12-month finding in the
the List of Endangered and Threatened
12-month finding on a petition to list Federal Register by December 15, 2008.
Species. Section 4(b)(3)(C) of the Act
the coaster brook trout (Salvelinus The deadline for the 12-month finding
requires that we treat a petition for
fontinalis) as endangered under the was extended to April 15, 2009, by
which the requested action is found to
Endangered Species Act of 1973, as mutual consent. On April 15, 2009, we
be warranted but precluded as though
amended (Act). The petition also asked filed an unopposed motion to extend
resubmitted on the date of such finding,
that critical habitat be designated for the the deadline for the coaster brook trout
that is, requiring that we make a
species. After review of all available 12-month finding to May 12, 2009.
subsequent finding within 12 months.
scientific and commercial information,
Such 12-month findings must be Species Information
we find that the coaster brook trout is
published in the Federal Register. This
not a listable entity under the Act, and Species Description
notice constitutes our 12-month finding
therefore, listing is not warranted. We
for the petition to list the U.S. Brook trout (Salvelinus fontinalis),
ask the public to continue to submit to
population of coaster brook trout. also called brook char or speckled trout,
us any new information that becomes
is one of three species in the genus
available concerning the taxonomy, Previous Federal Action
Salvelinus (chars) native to north and
biology, ecology, and status of coaster The Sierra Club Mackinac Chapter, eastern North America; the others being
brook trout and to support cooperative Huron Mountain Club, and Marvin J. lake trout (S. namaycush) and Arctic
conservation of coaster brook trout Roberson filed a petition, dated char (S. alpinus). The chars are a sub-
within its historical range in the Great February 22, 2006, with the Secretary of group of fishes in the salmon and trout
Lakes. the Interior to list as endangered the subfamily (Salmoninae) that is distinct
DATES: The finding announced in this ‘‘naturally spawning anadromous (lake- from the ‘‘true’’ trout and salmon sub-
document was made on May 19, 2009. run) coaster brook trout throughout its groups.
ADDRESSES: This finding is available on known historic range in the The brook trout throughout its range
the Internet at http:// conterminous United States’’ and to in eastern North America exhibits
www.regulations.gov at Docket Number designate critical habitat under the Act. considerable variation in growth rate,
[FWS–R3–ES–2008–0030]. Supporting The petition clearly identified itself as color, and other features, but generally
documentation for this finding is such and included the requisite can be distinguished from other char
available for inspection, by identification information for the and trout species by its olive-green to
appointment, during normal business petitioners, as required in 50 CFR dark brown back with a light yellow-
erowe on PROD1PC63 with PROPOSALS-1
hours at the U.S. Fish and Wildlife 424.14(a). On behalf of the petitioners, brown vermiculate pattern, sides with
Service, Region 3 Fish and Wildlife Peter Kryn Dykema, Secretary of the large yellow-brown spots and blue halos
Service Regional Office, 1 Federal Drive, Huron Mountain Club, submitted surrounding small, sporadic red and
Bishop Henry Whipple Federal supplemental information, dated May orange spots. Pectoral, pelvic, anal, and
Building, Fort Snelling, MN 55111. 23, 2006, in support of the original lower caudal fin have leading edges of
Please submit any new information, petition. This supplemental information white bordered by black with the
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Federal Register / Vol. 74, No. 95 / Tuesday, May 19, 2009 / Proposed Rules 23377
remainder predominantly reddish to temperature falling near the middle of trout is found at small and large geographic
orange. Sea-run brook trout become this range (Power 1980, p. 172). Thermal scales. Population genetic structuring is
silver with purple iridescence and show requirements within this range vary by common in brook trout throughout its range
red spots on the sides (Scott and life cycle phase and season (Scott and (Angers et al. 1999, pp. 1049–1050). Like
Crossman 1973, p. 208). many salmonids, brook trout tend to have a
Crossman 1973, p. 211; Blanchfield and
hierarchical population structure resulting
Distribution Ridgway 1997, p. 750; Baril and Magnan from the hierarchical design of the networks
2002, pp. 177–178). of streams and lake or coastal areas in which
The historical range of native brook The brook trout spawns in late they live, and a complicated life cycle that
trout extends along Hudson Bay in summer or autumn, the date varying leads to strong local adaptations. Taxonomic
Canada across the Provinces of with latitude and temperature. resolution can be even more complicated at
Manitoba, Ontario and Quebec, to Spawning takes place most often over the lake level when lakes include sympatric
Newfoundland and Labrador and south gravel beds but may be successfully (occupying the same or overlapping
to Nova Scotia and New Brunswick in accomplished over a variety of geographic area without interbreeding) but
Canada; and from eastern Iowa through substrates if there is spring upwelling or genetically divergent brook trout populations
northern Illinois, northern Ohio, and the a moderate current (Scott and Crossman such as in Lake Mistassini in Canada (Fraser
Great Lakes drainage (Minnesota, and Bernatchez 2008, p. 1197). This degree
1973, p. 210). Power (1980, p. 151) of genetic divergence that forms among
Michigan, Wisconsin), through the New describes rangewide brook trout
England States (New York, New populations is reflective of the reproductive
spawning, which occurs in the fall, connections (isolation) among the
Hampshire, Vermont, Maine, when day length and temperature are populations across the range of the taxon.
Massachusetts, Pennsylvania, New decreasing. In northerly regions and at
Jersey), large New England rivers (such high elevations, brook trout may spawn Six distinct genetic mitochondrial
as the Hudson River and Connecticut as early as late August and spawning (mtDNA) clades have been identified
River), and through the Appalachian may be delayed until December in throughout the range of brook trout in
Mountains in Maryland, Virginia, West southern areas. As is typical for eastern North America (Danzmann et al.
Virginia, North Carolina, South salmonids, females prepare redds 1998, p. 1307). These mtDNA clades
Carolina, Tennessee, south to Georgia (hollows scooped out for spawning) in reflect historical isolation in glacial
(MacCrimmon and Campbell 1969, pp. suitable gravel substrate. The female refugia or long periods of isolation in
1700–1702; MacCrimmon et al. 1971, p. then deposits her eggs in the redd where nonglacial areas in the southern part of
452; Scott and Crossman 1973, pp. 209– they are fertilized by a male. After the species’ range. The Wisconsin
210; Power 1980, p. 142). Naturalized spawning there is no further parental glacial advance which covered portions
populations of brook trout were involvement with the young. The redd of Canada covered all five Great Lakes
established as early as the late 1800s protects the eggs and allows an adequate 15,000 years ago (Bailey and Smith
beyond the historical native range by exchange of dissolved gases and other 1981, p. 1543). As these glaciers
introductions to waters in western materials during development. receded, brook trout recolonized the
North America, South America, Eurasia, Brook trout are carnivorous, feeding lakes from the Mississippi and Atlantic
Africa, and New Zealand (MacCrimmon opportunistically upon a variety of prey, refugia (Danzmann et al. 1998, pp. 1308,
and Campbell 1969, p. 1699, pp. 1703– such as worms, leeches, crustaceans, 1312). Given this pattern of glaciation,
1717). The current range of native brook aquatic insects, terrestrial insects, genetic diversity is greatest at the
trout still extends through Canada and spiders, mollusks, and fish (Scott and southern portion of the species’ range
down to Georgia in the U.S., but in Crossman 1973, p. 212). Anadromous and gradually decreases northward
many locations, populations have been (migrating from salt water to spawn in (Danzmann et al. 1998, pp. 1310–1311).
completely extirpated or have fresh water) forms vary their feeding As the most geographically isolated (for
contracted within this range towards behavior and prey items based on their tens of thousands of years), brook trout
upper stream reaches, higher altitudes, age and the environment, marine or in the southern part of the species’ range
or headwaters (EBJV 2006, p. 2). riverine, they are occupying (Newman (along the Appalachian Mountains
Distribution of Brook Trout in the Great and Dubois 1997, p. 9). Brook trout also south to Georgia) are the most diverse,
Lakes show diverse foraging behaviors; some containing all six mtDNA clades. The
individuals may be sedentary, eating Great Lakes contains three of the six
According to Bailey and Smith (1981,
crustaceans from the lower portion of mtDNA clades. Throughout the northern
p. 1549) and MacCrimmon and
the water column, whereas others in the portion of their range in Canada, brook
Campbell (1969, p. 1701), brook trout
same system may be more active and eat trout are the least genetically diverse,
are native to the lakes and tributaries of
insects from the upper portion of the with only a single mtDNA clade present.
Lakes Superior, Huron, Michigan, and
water column (McLaughlin et al. 1999, Within each of these lineages, there is
the tributaries of Lakes Erie and Ontario.
p. 386). This resource polymorphism evidence to suggest that selection is
Brook trout are not believed to have
may play a supplementary role in the driving rapid phenotypic divergence in
been present in Minnesota streams
extensive adaptive radiation (evolution some populations.
above barrier falls to Lake Superior
(Smith and Moyle 1944, p. 119) or of ecological variability within a rapidly Results based on microsatellite DNA
throughout most of the lower peninsula multiplying lineage; Smith and variation identified nine distinct genetic
of Michigan (MIDNR 2008a, pp. 1–2; ´
Skulason 1996) observed in this species. assemblages of brook trout in the U.S.
MacCrimmon and Campbell 1969, p. Genetics of Brook Trout (King 2009, unpub. data). Assemblages
1704). from the nonglacial southern part of the
A large amount of genetic variation for species’ range (along the Appalachian
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Habitat Requirements brook trout is distributed among populations Mountains from Pennsylvania to
(large Fst values). This pattern is heavily
Brook trout require clear, cold, well- influenced by the diverse ecological and life-
Georgia) in the U.S. are the most
oxygenated water to thrive. They are history characteristics of brook trout genetically divergent, and this
generally found in water ranging populations (population connectivity or divergence among the assemblages
between 41–68° Fahrenheit (5–20° isolation, philopatric tendency). This pattern generally decreases as the range
Celsius), with their likely preferred of highly differentiated populations of brook progresses northward.
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23378 Federal Register / Vol. 74, No. 95 / Tuesday, May 19, 2009 / Proposed Rules
Genetics of Brook Trout in the Great of genetic introgression of Lake Nipigon behavior (expressed as the adfluvial and
Lakes hatchery fish into native populations of anadromous ecotypes) by any
Populations from Lake Superior and brook trout from six tributaries to Lake individual fish will be partially in direct
tributaries to Lake Erie form two of the Superior’s Nipigon Bay (D’Amelio and response to its environment. Phenotypic
nine genetic assemblages of brook trout Wilson 2008, p. 1222), despite decades expression of more than one form may
in the U.S. The Lake Erie populations of stocking. A study by Scribner et al. be expected in a population located in
are the most divergent assemblage from (2006, pp. 3–4) examined nine brook a variable environment containing
the northern part of the species’ range. trout populations from Lake Superior habitats for several ecotypes. The
Lake Superior populations are similar in tributaries on the south shore of amount of phenotypic plasticity a
the degree of genetic divergence to the Michigan and four hatchery strains population will exhibit for the migratory
remaining northern assemblages outplanted into those tributaries. This trait also has a heritable genetic basis
grouping with the average genetic study used similar methods to D’Amelio and will be determined by the intensity
distance between brook trout and Wilson (2008). Scribner et al. (2006, and type of selective pressures that
populations in the U.S. Samples from p. 8) concluded that hatchery stocking population experiences (Via and Lande
the rest of the Great Lakes were not appears to have minimal if any impact 1985, pp. 517–519; Theriault et al. 2008,
available for analysis. Although brook of on brook trout. pp. 418–419).
Adoption of migratory adfluvial form
trout in the Great Lakes do not contain Brook Trout Life-History Diversity or stream-resident life-history form in
any wholly unique mtDNA clades, they An individual’s ability to produce brook trout has been modeled under a
do contain a large amount of the genetic multiple phenotypes (visible or conditional strategy framework where
variation in a confined portion of the observable characteristics) in response environmentally influenced threshold
range (Danzmann et al. 1998, pp. 1310– to its environment is termed phenotypic traits determine which ecotype a fish
1311). plasticity (Scheiner 1993, p. 36). Recent will adopt (Hendry et al. 2004, pp. 124–
Native populations of brook trout in studies have recognized the role of 125). Growth rate efficiencies, body size,
Lake Superior in most cases have phenotypic plasticity as a major source and concentration of juvenile hormone
retained their native genetic of phenotypic variation in natural have all been identified as potential
characteristics despite the stocking of populations (Price et al. 2003, p. 1438). threshold traits (Theriault and Dodson
hatchery fish from sources outside and The brook trout exhibits remarkable 2003, pp. 1155–1157). Theoretical work
within the Lake Superior basin. In Lake phenotypic plasticity across its natural by Ridgway (2008, p. 1185) and Uller
Superior, the intensity and purpose of range. This plasticity allows it to thrive (2008, pp. 436–437) also provide
stocking has varied over time and space. in a variety of environments, from cold information to suggest parental effects
For example, Minnesota tributaries to subarctic regions, through temperate are important to the expression of
Lake Superior have been stocked with zones and in southern refugia in eastern alternate ecotypes of brook trout. These
hatchery strains that originated from North America, and in a range of places parental effects describe an affect of the
outside of the Great Lakes Basin to where it has been introduced (Power parental phenotype on the offspring’s
provide fishing opportunities above fish 1980, p. 142). Although primarily a phenotype such as coaster females
passage barriers (Wilson et al. 2008, p. stream-dwelling species, brook trout producing larger eggs and spawning in
1312). Until the early 1990s, most of the also occupy inland lakes and coastal different locations from stream-resident
stocked fish in Lake Superior were waters. Because of the variety of the ecotypes, influencing the habitat use
domesticated strains from outside the freshwater, estuary, and ocean (Morinville and Rasmussen 2006, pp.
Great Lakes basin (Schreiner et al. 2008, environments, migratory plasticity is 701–702) and growth rate at the juvenile
p. 1357), although many stocking events also favored. The brook trout’s dispersal stage (Perry et al. 2005, p. 1358). These
were undocumented and records of subsequent to receding glaciation, and differences in growth rate and habitat
early stocking events are incomplete separation into isolated breeding stocks use impact potential threshold traits.
(Wilson et al. 2008, p. 1312). These in diverse habitats subject to an array of Work on sympatric brook trout life
stocking efforts were not targeted at natural and man-made influences have forms at young ages largely comes from
rehabilitation and from that perspective, all contributed to this variability (Power a few studies on anadromous
results were poor. The stocked fish were 1980, p. 142). populations. Morinville and Rasmussen
not behaviorally or evolutionarily Brook trout display considerable life- (2003) studied the bioenergetics of
adapted to the environment in which history variation throughout their native young brook trout exhibiting
they were planted, criteria known to range (Huckins and Baker 2008, p. anadromous migratory and stream-
limit survival and reproductive success 1229). Brook trout across its range resident life tactics. They found that the
(Schreiner et al. 2008, p. 1357). exhibit a variety of life-history types anadromous migrants have higher
Burnham-Curtis (2001, p. 2) concluded (polymorphisms or ecotypes), including metabolic costs and had consumption
that hatchery fish have had little fluvial (stream-dwelling), adfluvial rates 1.4 times that of stream residents
reproductive success in Lake Superior (migrating between lakes and streams), but growth efficiencies of the
streams based on her examination of 36 lacustrine (lake-dwelling), and anadromous form were lower than that
tributaries to Lake Superior and 9 anadromous (migrating from salt water of residents. Spatial utilization of
hatchery stocks outplanted into the lake. to spawn in fresh water) forms. habitat differed among the life tactics as
However, the genetic methods used by Understanding life-history diversity in a well, with migratory individuals
Burnham-Curtis provided low power to species requires knowledge of the occupying faster-flowing waters
detect genetic introgression of hatchery evolutionary history, ecological setting, compared to the resident fish which
fish into native populations (Wilson et and reproductive relationships among used pool areas (p. 408). They
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al. 2008, p. 1312). A recent study by ecotypes. Reproductive interactions concluded that migrant brook trout have
D’Amelio and Wilson (2008, p. 1215) between ecotypes are reflected by the noticeably different energy budgets than
used genetic methods with high power magnitude and pattern of genetic resident brook trout from the same
to detect genetic introgression of differentiation observed between life- system (p. 406). Morinville and
hatchery fish into natural populations. history phenotypes at neutral genetic Rasmussen (2008) also investigated
This study documented only low levels markers. The expression of migratory morphological differences between life
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Federal Register / Vol. 74, No. 95 / Tuesday, May 19, 2009 / Proposed Rules 23379
tactics. The authors concluded that 64 centimeters (cm) and 341–3632 The long-term persistence of a
migrant brook trout were found to be grams (g)) versus (5–15 inches (13–38 metapopulation requires a balance
more streamlined (narrower and cm) and (less than 1 pound (<454 g), be between local extinction and
shallower bodies) than resident brook more fecund (1500–3000 eggs per recolonization of constituent
trout, and these differences persisted female versus 100–1500 eggs per populations (see Hanski 1998 for a
into the marine life of the migrant fish female), and move greater distances (up review of metapopulations). Dispersing
(pp. 175, 183). The differences were to 19–217 miles (30–350 kilometers individuals offset local population
powerful enough to derive discriminant (km)) versus less than 19 miles (30 km)) extinction by providing a means for
functions using five of the measured (Scott and Crossman 1973, pp. 208, 210, recolonization (Brown and Kodric-
traits allowing for accurate classification 211; Power 1980, p. 157; Becker 1983, Brown 1977, p. 448; Reeves et al. 1995,
of juvenile brook trout as either migrant pp. 318, 320; Ritchie and Black 1988, p. 340). Dispersing individuals also
or resident with an overall correct pp. 19, 50, 51; Quinlan 1999, pp. 11, 12, provide for gene flow among discrete
classification rate of 87 percent. 14, 16, 17, 20; Swainson 2001, pp. 40, populations, countering losses of
A study by Theriault et al. (2007b, p. 41, 60, 64; WIDNR and USFWS 2005, p. genetic fitness while still allowing the
61) found that sympatric anadromous 16; Huckins and Baker 2008, pp. 1239, development and distribution of unique
and fluvial brook trout in the Sainte- 1241; Huckins et al. 2008, pp. 1328, adaptive traits (Ingvarsson 2001, p. 63;
Marguerite River in Quebec belonged to 1329, 1337; Mucha and Mackereth 2008, Tallmon et al. 2004, p. 494). Thus, the
a single gene pool. Phenotypic plasticity p. 1210; Schram 2008a, pers. comm.; coaster life-history forms are important
is, therefore, a major force driving the Chase 2008, pers. comm.). to the long-term viability of brook trout
expression of these two life histories Coasters have been historically populations throughout Lake Superior.
from this population. Evolution of documented in Lakes Superior, Huron,
Genetic studies of stream-resident
phenotypic plasticity in this population and Michigan brook trout populations
(fluvial life form) brook trout show
was influenced by mating systems with (Bailey and Smith 1981, p. 1549;
substantial genetic structuring among
most of the mating between different Dehring and Krueger 1985, p. 1;
populations in Michigan, Wisconsin,
morphotypes occurring between fluvial Enterline 2000, p. 1; MIDNR 2008a, pp.
Minnesota, and Canada characterized by
males and anadromous females. 1–2). However, Lake Superior is the
distinct regional groupings or
Additional work in this system only Great Lake with extant coaster
metapopulations (Burnham-Curtis 1996,
demonstrated significant heritability for forms of brook trout, and all available
pp. 10–11; Burnham-Curtis 2001, p. 10;
life-history tactic and for body size literature is from this area. Coasters in
(Theriault et al. 2007a, pp. 7–8) the Great Lakes are found in Canada and Sloss et al. 2008, p. 1249; Wilson et al.
indicating expression of life-history the U.S. in substantially fewer locations 2008, p. 1312; Scribner et al. 2008, p. 9).
tactic in this population can be effected than they were historically (Newman et In studies aimed at determining genetic
by natural or artificial selection. al. 2003, p. 39). Populations in the Great differences between the coaster
Lakes basin with these life-history forms polymorphism and stream-resident fish
Life-History Diversity in Great Lakes occupying tributaries connected to the
are documented within Canada in
Brook Trout lake, molecular genetic work in Lake
tributaries to Nipigon and Black Bays,
Fish that complete their life cycle the Nipigon River, Lake Nipigon and the Superior indicates that coasters and
exclusively in tributaries to the Great Pancake River in the eastern part of stream-resident brook trout occupying
Lakes exhibit the fluvial life history and Lake Superior (Newman et al. 2003, p. tributaries to the first barrier are parts of
are defined as stream residents. 39; Chase and Swainson 2009, pers. the same population (D’Amelio and
‘‘Coaster’’ (the subject of the petition) is comm.). Within the U.S. portion of the Wilson. 2008, p. 1221; Scribner et al.
a regional term for a life-history variant Great Lakes basin, populations that 2008, p. 9; Stott 2008, p. 5). Work
of brook trout in the Great Lakes express the coaster form occur in Isle investigating the genetic differences of
(Burnham-Curtis 2001, p. 2; Wilson et Royale National Park in Tobin Harbor, various tributaries to the lake found
al. 2008, p. 1) which use lake waters of Big and Little Siskiwit Rivers, and distinct differences among populations
the Great Lakes for all or a portion of its Washington Creek as well as on the of brook trout in each tributary to Lake
life cycle (Becker 1983, p. 320). The south shore of Lake Superior in the Superior (Burnham-Curtis 1996, p. 10;
coaster form can be further divided into Salmon Trout River (Newman et al. Burnham-Curtis 2000, p. 7; Burnham-
an adfluvial ecotype that migrates from 2003, p. 39). Curtis 2001, p. 10; D’Amelio and Wilson
the stream to the lake and back into As previously stated, brook trout 2008, p. 1222; Sloss et al. 2008, p. 1249;
tributaries to spawn and a lacustrine populations within the upper Great Scribner et al. 2008, p. 9). Within Lake
ecotype that completes its life cycle Lakes exhibit fluvial, adfluvial, and Superior, regional genetic differences
entirely within the lake (Huckins et al. lacustrine life-history forms, coasters are evident between brook trout
2008, p. 1323). In the Great Lakes comprising the latter two forms. populations in Nipigon Bay, Isle Royale,
region, spawning usually occurs from Populations of brook trout in Lake and Lake Nipigon-Grand Portage
mid-September through mid-November. Superior likely function as types of (Wilson et al. 2008, p. 1313). Adfluvial
Distinct life histories associated with metapopulations, with the coaster life brook trout are thought to be the
the coaster and stream-resident types forms serving as dispersers (D’Amelio mechanism providing genetic
result in different physical, and Wilson 2008, p. 1222; Sloss et al. communication among these regional
demographic, and ecological 2008, p. 1249). The viability of a aggregations and straying of a coaster
characteristics for the forms (Huckins et metapopulation is strongly contingent was documented in Nipigon Bay and at
al. 2008, p. 1337; Huckins and Baker upon maintaining dispersal among Isle Royale (D’Amelio et al. 2008, p.
2008, p. 1241; Ridgway 2008, p. 1185). populations. Although brook trout 1347; Stott 2008, p. 4). Sloss et al. (2008)
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Specifically, coasters tend to live longer exhibit spawning site fidelity, investigated genetic differentiation
than stream residents (5–8 years versus individuals exhibiting the adfluvial life among four Wisconsin populations of
less than 5 years), reach maturation later forms in Lake Superior have also been stream-resident brook trout. His work
(females at 2–4 years versus 1–2 years), shown to stray or disperse among found significant differentiation among
attain larger length and weight as adults streams (D’Amelio and Wilson 2008, p. populations to the point the authors
(12–25 inches and 0.75–8 pounds (30– 1222; Mucha and Mackereth, p. 1211). observed that for these populations,
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23380 Federal Register / Vol. 74, No. 95 / Tuesday, May 19, 2009 / Proposed Rules
there appears to be a near complete lack heterogeneity and favors an increase in recovery for expression of the adfluvial
of gene flow among them resulting in trait reaction norm (the pattern of form after fishing selection is reduced or
genetic drift (Sloss et al. 2008, p. 1249). visible characteristics produced by a eliminated because there is not
None of these isolated populations are given genetic makeup of an organism automatically equal directional
thought to currently have adfluvial under different environmental selection in the opposite direction for
ecotypes as part of the population. This conditions; Sultan and Spencer 2002, p. expression of the adfluvial form. In the
observation is consistent with the 281). Alternatively, the adfluvial and case of the coaster, habitat degradation
contemporary lack of an adfluvial form lacustrine ecotypes on Isle Royale are and competition from nonnative salmon
that historically provided the regional physically isolated and in this situation, may exclude brook trout from habitats
genetic connection for the three adaptive radiation would be favored that would allow juvenile brook trout to
metapopulations previously mentioned. over the evolution of phenotypic achieve growth rates necessary to
As characterized in the entire brook plasticity (Price 2003, pp. 1437–1438). express the adfluvial coaster ecotype
trout species, phenotypic plasticity and If phenotypic plasticity is the source (Huckins et al. 2008, pp. 1337–1339).
adaptive radiation (Schluter 2000, p. 1) of differences observed between stream- Additionally, metapopulation structure
appear to represent the continuum of resident and brook trout, then these mediated by coaster brook trout
evolutionary processes underlying the ecotypes are expressed in a single (D’Amelio et al. 2008, p. 1348) favors
expression of life-history variation in population and represent the extremes plasticity over adaptive genetic
populations of brook trout in Lake of the reaction norm for migratory differences among populations (Sultan
behavior. Scribner et al. (2008, p. 10) and Spencer 2002, p. 281). Loss of
Superior (Ardren 2008, pp. 1–2). As
did not observe genetic differences coasters in most populations in Lake
stated above, plastic responses allow
between sympatric adfluvial brook trout Superior has reduced migration among
individuals to obtain high fitness in new
and presumed stream-resident ecotypes populations (Sloss et al. 2008, p. 1249)
environments. Alternatively, adaptive
in the Salmon Trout River on the south resulting in a reduction in
genetic differentiation among
shore of Lake Superior. Analysis of environmental heterogeneity favoring a
populations may provide evolutionary
microsatellite DNA provided high decrease in the reaction norm of traits.
advantages. First, there are fitness costs
statistical power to detect genetic These studies demonstrate that human-
to being highly plastic. For example,
differences between ecotypes. In fact, induced selective forces can alter the
plastic genotypes need to maintain
the authors did observe highly reaction norm for a population which
sensory and developmental pathways in significant genetic differences between
order to induce plastic responses that can result in the loss of plasticity
brook trout sampled above and below needed to express the coaster life-
are not required by nonplastic the impassable waterfall in this system.
genotypes (Relyea 2002, pp. 272–273). history forms.
In addition, when collections from the
Secondly, if the plastic response to a Salmon Trout River were compared Brook trout experts contend that if
new environment is insufficient and with native brook trout populations environmental conditions are suitable
directional selection favors an extreme sampled from 10 other nearby (i.e., threats are abated), the adfluvial
phenotype, there will be genetic tributaries, the lowest pairwise measure life form of brook trout populations in
evolution of the trait (adaptive of genetic distinction was observed Lake Superior can be readily
radiation). Therefore, if a population of between the resident and adfluvial reconstituted from purely resident stock
brook trout experiences divergent ecotypes sampled below the waterfall in (USFWS 2009, p. 8); this is believed
selection in stable environments, we the Salmon Trout River. D’Amelio and unlikely for other salmonids (e.g.,
would expect the ecotypes to evolve Wilson (2008, p. 1221) used similar Oncorhynchus mykiss). This assertion is
genetic differences and nonplastic forms methods to document that adfluvial predicated on three premises. First,
because the cost of maintaining the brook trout in the Nipigon Bay were not adult brook trout of one ecotype may
phenotypic plasticity would be too high. genetically distinct from presumed produce offspring of the other ecotype.
Findings in the Salmon Trout River resident brook trout sampled from For example, two resident fish could
indicate phenotypic plasticity plays a tributaries to the bay. These findings in breed and produce offspring that exhibit
major role in the expression of the the Salmon Trout River and the Nipigon both the adfluvial and fluvial life-
adfluvial and fluvial ecotypes while Bay area indicate phenotypic plasticity history strategies. Further, stream-
information from Isle Royale indicates likely plays a major role in the resident and adfluvial ecotypes from the
adaptive radiation has occurred expression of the adfluvial and fluvial same population interbreed. This means
separating adfluvial and lacustrine ecotypes. that within a stream, individuals that
coaster ecotypes. Migratory plasticity Theriault et al. (2008, pp. 417–419) exhibit the resident and adfluvial forms
could be favored in situations where used an eco-genetic model to reside within and are drawn from the
adfluvial and stream-resident brook demonstrate that intensive harvest of same population. Second, the chars
trout co-occur because the environments anadromous fish reduces the probability (genus Salvelinus), including brook
they occupy are highly variable of migration in brook trout over the trout, show greater phenotypic plasticity
(Huckins et al. 2008, p. 1324; Ridgway course of 100 years. This study provides than most other salmonids. Adfluvial
2008, pp. 1186–1187). The alternating a basic framework for understanding brook trout do not require substantial
selection patterns associated with these how fisheries-induced selection physiological changes (for example,
diverse and variable environments (mortality from fishing) influences the smoltification) to successfully migrate
create a fitness advantage for plastic evolution of alternate life-history tactics and survive in the lake environment.
genotypes over nonplastic genotypes. In that are expressed by phenotypic Thus, the fitness costs to maintain the
addition, the metapopulation structure plasticity. For example, directional genetic code for plasticity are likely less
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mediated by coaster brook trout selection imposed by fishing-induced relative to saltwater-dwelling
(D’Amelio and Wilson 2008, p. 1222; mortality on coaster brook trout confers salmonids. Hence, it is reasonable to
Ridgway 2008, p. 1181) favors plasticity high fitness to the survivors of the expect a brook trout population will
over adaptive genetic differences among fishery but not necessarily with respect maintain the ability (genetic code) to
populations because dispersal among to natural selection. There is also express the full array of life forms over
populations increases environmental uncertainty regarding the rate of time. Third, life-history strategy for
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Federal Register / Vol. 74, No. 95 / Tuesday, May 19, 2009 / Proposed Rules 23381
brook trout is strongly controlled by ditching small streams) ranks as the unpub. data). The current specific status
environmental conditions or triggers. As most widely distributed impact to brook of most of these populations is not
such, the experts believe that, provided trout across the eastern U.S. (EBJV 2006, known, but they are described by the
the necessary environmental conditions p. 2). Climate change presents a Michigan, Minnesota, and Wisconsin
or triggers exist, life forms can be significant threat to brook trout, with natural resource agencies as stable and
expressed even if temporally lost from some southern portions predicted to self-sustaining in the upper Great Lakes
a population. lose between 53–97 percent of their (Holtz 2008, p. 2; MIDNR 2008a, p. 49;
brook trout habitat due to high water Schreiner and Ebbers 2008, pers.
Current Population Status of Brook
temperatures (Flebbe 2006, p. 1379). comm.).
Trout In coldwater tributaries to the upper
While some uncertainty remains about
The current range of native brook the exact temperature increase that will Great Lakes, brook trout were
trout remains generally unchanged, result from climate change, the present historically distributed from the river
extending through much of eastern range of brook trout is predicted to mouth upstream to the headwaters or to
North America, from eastern Canada, shrink, particularly in the southern impassible barriers (Smith and Moyle
south through the Great Lakes and Appalachians (Hudy et al. 2005, p. 5). 1944, p. 119; Moore and Braem 1965, p.
northeast to Georgia in the U.S. Nonnative species are now present 19; Goodier 1982, p. 111; Becker 1983,
However, populations throughout this throughout most of the range (Parsons p. 321; WIDNR and USFWS 2005). The
range have experienced significant 1973, p. 5). Interactions with these brook trout numbers in these stream
declines. The current range of native nonnatives are considered to be among reaches once numbered in the hundreds
brook trout started diminishing over the the most significant biological threats to to thousands (Huckins and Baker 2008,
past 200 years as a result of ecosystem brook trout rangewide (Peck 2001, p.13; p. 1231). A 30-year data set from
disruption following European Hudy et al. 2005, p. 3; EBJV 2006, pp. Wisconsin tributaries shows that, in
settlement of North America (Newman 2–3, 5). Brown trout have been shown streams historically occupied solely by
and DuBois 1997). Habitat destruction to displace or reduce stream brook trout, brook trout have contracted
by forestry, agricultural practices, populations of brook trout throughout into upstream sections and are now
industrial water use, dams, and their natural range (Nyman 1970, p. 348; nearly absent in lower reaches (WIDNR
pollution were responsible for this Fausch and White 1981, p. 1226; Waters 2008, unpub. data). Brook trout
decline (Power 1980, p. 141). Brook 1983, p. 144). Encroachment by rainbow abundance has declined despite the
trout were once present in nearly every trout has also been documented in the persistence of suitable conditions for
coldwater stream and river in the contraction of the range of native brook brook trout and high numbers of
eastern U.S. and Canada, but trout across their native range (Kelly et juvenile nonnative salmonids (WIDNR
populations began to disappear as early al., 1980, pp. 9–10; Power 1980, p. 195; 2008, unpub. data). In Wisconsin
agriculture, timber, and textile practices Larson and Moore 1985, p. 200). Species tributaries to Lake Superior, the
and industries cleared the region’s such as small mouth bass and yellow distribution of stream-resident brook
protective forests and degraded the perch are considered to be significant trout populations has declined by nearly
streams with sediment and pollution competitors with lake-dwelling brook 50 percent from historical levels
(Power 1980, p. 141; EBJV 2006, p. 1). trout (EBJV 2006, pp. 22, 28, 34). (WIDNR and USFWS 2005, p. 17).
Throughout much of their natural Historically, 119 tributaries to Lake
range, remaining stream populations Current Population Status of Brook Superior and purportedly 6 Lake Huron
have retreated into extreme headwater, Trout in the Upper Great Lakes streams supported populations of brook
high elevation, or upstream reaches Brook trout populations throughout trout with coaster ecotypes (Newman et
(EBJV 2006, p. 2). In the eastern U.S., the upper Great Lakes region are al. 2003, pp. 31–38; Enterline 2000, p.
healthy stream populations of brook relatively common and geographically 30). Once abundant and widespread
trout (wild brook trout occupying 90– widespread, although distribution and throughout the northern portions of the
100 percent of their historical habitat) abundance is much reduced from Great Lakes, populations of brook trout
exist in only 5 percent of subwatersheds historical levels (Power 1980, p. 195; that still exhibit the coaster ecotypes are
(EBJV 2006, p. 2). Anadromous stocks Becker 1983, pp. 321–322; WIDNR and presently limited to a few locations
along the U.S. coast and in many USFWS 2005, p. 17). Dramatic declines (Dehring and Krueger 1985, p. 1; Bailey
Canadian rivers have been decimated by in abundance and distribution of both and Smith 1981, p. 1549; Goodyear et al.
dams and estuarine pollution (Power coaster and stream-resident ecotypes of 1982, pp. 63–65; Enterline 2000, p. 30;
1980, p. 195). In the southern portion of brook trout occurred in the upper Great Newman et al. 2003, p. 39; Schreiner et
its range (southern Appalachian Lakes from the 1850s to mid-1900s al. 2008, p. 1351; Mucha and Mackereth
Mountains), brook trout populations (Goodier 1982, pp. 110, 112; Ritchie and 2008, p. 1). Although self-sustaining
have declined by 75 percent, persisting Black 1988, p. 15; Newman and Dubois populations of stream-resident brook
now only in isolated headwater reaches 1997, pp. 4–6; Enterline 2000, p. 1; trout are currently present in 56 of 58
(EBJV 2006, p. 6). WIDNR and USFWS 2005, pp. 17–18; U.S. streams and in all 61 Canadian
Various threats are persistent across Schreiner et al. 2008, p. 1305; Schreiner streams identified in the Brook Trout
the brook trout range. Most of them et al. 2008, p. 1351; Huckins et al. 2008, Rehabilitation Plan for Lake Superior as
involve habitat loss and degradation, p. 1322). historically supporting populations with
such as poor land management, high There are presently at least 200 coaster ecotypes (Newman et al. 2003,
water temperature, sedimentation streams with documented brook trout pp. 31–37; Quinlan 2008, unpub. data;
(roads), urbanization, degraded riparian populations in the upper Great Lakes Schreiner 2008, pers. comm.; Schram
habitat, stream fragmentation (roads), (Moore and Bream 1965, p. 19; Goodier 2008c, pers. comm.; Scott 2008, pers.
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dam inundation/fragmentation, and 1982, p. 110; Enterline 2000, p. 30; comm.; Chase 2009, pers. comm.), only
forestry practices (EBJV 2006, pp. 3, 5). Newman et al. 2003, pp. 31–37; Quinlan 18 populations with coaster ecotypes
Poor land management associated with 2004, unpub. data; Bassett 2009, unpub. still persist there (15 stream-spawning–
agriculture (such as clearing streamside data; Ward 2007, p. 16; Schram 2008b, adfluvial, and 3 lake-spawning–
vegetation, over-grazing sensitive areas, pers. comm.; Scott 2008, pers. comm.; lacustrine) (Goodyear 1982, pp. 63–65;
ineffectively managing nutrients, and Chase 2009, pers. comm.; OMNR 2009, Quinlan 1999, p. 19; Ritchie and Black
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23382 Federal Register / Vol. 74, No. 95 / Tuesday, May 19, 2009 / Proposed Rules
1988, p. 15; Swainson 2001, p. 41; Creek, Wisconsin (USFWS and WIDNR population is a species or subspecies for
Newman et al. 2003, pp. 28–39; 2003, p. 5). Supplementation stocking the purposes of the Act: ‘‘The Secretary
Enterline 2000, p. 30; Chase 2009, pers. occurred in Siskiwit Bay, Isle Royale, shall rely on standard taxonomic
comm.). from 1999 to 2005. Data collected to distinctions and the biological expertise
Over the last decade, the presence of date indicates limited success with of the Department and the scientific
coaster brook trout has been confirmed these efforts (Newman et al. 1999, p. 2; community concerning the relevant
in other locations within the upper Quinlan 2008, pers. comm.; Stott and taxonomic group’’ (50 CFR 424.11). As
Great Lakes. Surveys, and in some cases Quinlan 2008, p. 22). Reintroduction previously discussed, coaster brook
genetic analysis, have confirmed the efforts in Michigan have recently been trout are classified as Salvelinus
presence of brook trout with coaster terminated in the Gratiot, Little Carp, fontinalis, the same as other brook trout,
ecotypes in the following locations; Hurricane, and Mosquito Rivers and and as such we do not consider the
Minnesota tributaries to Lake Superior Sevenmile Creek (Scott 2007, pers. coaster form of the brook trout to
(Newman et al. 1999, p. 2; Burnham- comm.; Loope 2007, pers. comm.). constitute a distinct species or
Curtis 2000, p. 4; Pranckus and Threats to brook trout across its native subspecies. Since the coaster brook trout
Ostazeski 2003, p. 5; Ward 2007, p. 16), range are also acting on brook trout is not a distinct species or subspecies,
three Michigan tributaries to Lake within the upper Great Lakes. A primary we then evaluated whether the coaster
Superior (Stimmel 2006, p. 56; MIDNR impact is the presence of introduced brook trout is a distinct vertebrate
2008a, p. 2; Leonard 2009, pers. comm.), fishes (e.g., non-native salmonids). population segment to determine
along the shoreline of the Red Cliff Introduced salmonids have competitive whether it would constitute a listable
Indian Reservation, Wisconsin (Stott and predatory impacts on brook trout, entity under the Act.
and Quinlan 2008, p. 21), and in Little although the precise mechanisms may To interpret and implement the
Todd Harbor and Rock Harbor, Isle not be fully understood and the distinct vertebrate population segment
Royale (Gorman et al. 2008, p. 1257). magnitude of impact may vary by (DPS) provisions of the Act and
The origin of these fish is unknown and species, population size, and Congressional guidance, the Service and
natural reproduction of fish exhibiting environmental conditions. The decline the National Marine Fisheries Service
the coaster ecotype has not been or loss of the migratory coaster form has (now the National Oceanic and
confirmed, therefore these locations are diminished connectivity among Atmospheric Administration—
not identified as supporting self- populations that once operated as Fisheries), published the Policy
sustaining populations. However, they metapopulations. Populations that occur Regarding the Recognition of Distinct
have potential to be self-sustaining in such isolated patches can be lost, Vertebrate Population Segments (DPS
populations, as outlined by Schreiner et increasing the possibility of extirpation. Policy) in the Federal Register on
al. (2008). As a species, brook trout are known to February 7, 1996 (61 FR 4722). Under
Abundance of individuals in be highly susceptible to exploitation by the DPS Policy, three elements are
populations exhibiting the coaster anglers (Newman and Dubois 1996, p. 3; considered in the decision regarding the
ecotypes is stable or increasing in Newman et al. 2003, p. 11; Huckins et establishment and classification of a
several regions of Lake Superior. In the al. 2008, p. 1322). Overharvest was a population of a vertebrate species as a
Salmon Trout River, Michigan, primary cause of the decline of Great possible DPS. These are applied
abundance as determined by video Lakes brook trout populations by the similarly for additions to and removals
surveillance increased from 118 to 243 early 1900s, especially the coaster from the List of Endangered and
in the period from 2004 to 2006 (MIDNR ecotype, and continues to threaten some Threatened Wildlife and Plants. These
2008a, p. 6). In the Nipigon River, angler populations within the region (Newman elements are (1) the discreteness of a
catch per hour has increased from the and Dubois 1996, p. 1; Huckins et al. population in relation to the remainder
late 1980s to the present, while harvest 2008, p. 1322; Schreiner et al. 2008, p. of the species to which it belongs, (2)
has decreased substantially (Houle 1356). Climate change also presents a the significance of the population
2004, p. 13). In South Bay, Lake threat to upper Great Lakes brook trout, segment to the species to which it
Nipigon, estimates of spawner through increased water temperatures, belongs, and (3) the population
abundance continue to increase and leading to increased presence of segment’s conservation status in relation
currently number about 600 fish—up nonnative competitors and predators to the Act’s standards for listing,
from fewer than 100 in the recent past, along with a decrease in habitat delisting, or reclassification.
but still fewer than the estimated 2,500 suitability. Although the enormous
present in the mid-1900s (Swainson Distinct Vertebrate Population Segment
coldwater reservoir within the lake
2009, pers. comm.). In Tobin Harbor, Analysis
environment represents a potential
Isle Royale National Park, Michigan, refuge for Great Lakes brook trout, In accordance with our DPS Policy,
estimates of adult brook trout from predicted impacts in both stream and this section details our analysis of the
1996, 2001, and 2008 has remained lake environments still represent a first two elements used to assess
around 200–250 fish (USFWS potential threat to their long-term whether a vertebrate population
unpublished data). Relative abundance viability. segment under consideration for listing
based on shoreline electrofishing index may qualify as a DPS. These elements
surveys in Tobin Harbor from 1997 to Defining a Species Under the Act are (1) the population segment’s
2008 has fluctuated from 0.3 per hour to Section 3(16) of the Act defines discreteness from the remainder of the
16.7 per hour (USFWS 2008, unpub. ‘‘species’’ to include ‘‘any species or species to which it belongs and (2) the
data). subspecies of fish and wildlife or plants, significance of the population segment
There are reintroduction stocking and any distinct vertebrate population to the species to which it belongs.
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efforts ongoing in several streams on the segment of fish or wildlife that Discreteness refers to the ability to
Grand Portage Indian Reservation interbreeds when mature’’ (16 U.S.C. circumscribe a population segment from
(Newman and Johnson 1996, p. 4), Red 1532 (16)). Our implementing other members of the taxon based on
Cliff Indian Reservation, Keweenaw Bay regulations at 50 CFR 424.02 provide either (1) physical, physiological,
Indian Community Reservation further guidance for determining ecological, or behavioral factors or (2)
(Donofrio 2002, p. 1), and in Whittlesey whether a particular taxon or international boundaries that result in
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Federal Register / Vol. 74, No. 95 / Tuesday, May 19, 2009 / Proposed Rules 23383
significant differences in control of basin, and (2) describe and analyze an population segment are physically
exploitation, habitat management, upper Great Lakes ‘‘coaster-only’’ isolated from other populations of brook
conservation status, or regulatory population segment, which includes trout as the result of the physical
mechanisms in light of section 4(a)(1)(B) only the coaster forms—adfluvial and separation between the drainage of the
of the Act. lacustrine ecotypes—of brook trout Great Lakes basin and neighboring
Under our DPS Policy, if we have throughout the documented historical drainages. Consequently, brook trout in
determined that a vertebrate population range of brook trout in the Great Lakes the Great Lakes basin meet the
segment is discrete, we consider its basin. discreteness criterion of being markedly
biological and ecological significance to We find that neither of the population separate from other members of the
the larger taxon to which it belongs in segments analyzed constitute a valid brook trout taxon.
light of Congressional guidance (see DPS, and therefore the first petitioned
Senate Report 151, 96th Congress, 1st International Border
entity, coaster brook trout throughout
Session) that the authority to list DPSs their historical range in the U.S., is not We presently do not find that the
be used ‘‘sparingly’’ while encouraging a valid DPS. To address the second and brook trout in the Upper Great lakes on
the conservation of genetic diversity. To third petition requests, we focused on either side of the international United
evaluate whether a discrete vertebrate the brook trout population in the States border with Canada are discrete
population may be significant to the Salmon Trout River and evaluated due to differences in control of
taxon to which it belongs, we consider whether it qualified as a DPS per our exploitation, management of habitat,
the best available scientific evidence. policy. We find that the brook trout conservation status, or regulatory
This evaluation may include, but is not population in the Salmon Trout River mechanisms that are significant in light
limited to: (1) Evidence of the also does not constitute a valid DPS. of section 4(a)(1)(D) of the Act.
persistence of the discrete population The remainder of this section details the
segment in an ecological setting that is evaluation of these population segments Conclusion for Discreteness
unusual or unique for the taxon; (2) as DPSs per our 1996 DPS Policy. In conclusion, we determine that the
evidence that loss of the population Upper Great Lakes brook trout
segment would result in a significant Upper Great Lakes All Brook Trout
Population Segment population segment, as defined here, is
gap in the range of the taxon; (3) discrete from the remainder of the brook
evidence that the population segment This population segment trout taxon. This discreteness arises
represents the only surviving natural encompasses the range of brook trout from the population segment’s physical
occurrence of a taxon that may be more populations within the Great Lakes isolation from the remainder of the
abundant elsewhere as an introduced basin that currently or historically taxon. Therefore, we will now consider
population outside its historical range; occupied both the tributary and lake the potential significance of this discrete
and (4) evidence that the discrete environments (including stream- population segment to the remainder of
population segment differs markedly in resident, adfluvial, and lacustrine the taxon.
its genetic characteristics from other ecotypes of brook trout). Although
populations of the species. technically not one of the ‘‘Great Significance
The first step in our DPS analysis was Lakes,’’ we include Lake Nipigon in
to identify population segments of the We have determined that the
Canada in this population because it is population of brook trout in the Upper
brook trout to evaluate. The petition part of the Great Lakes drainage. The
asked us to (1) ‘‘list as ‘endangered’ the Great Lakes meets the discreteness
best available information indicates the elements of the DPS policy, and as such,
naturally spawning anadromous (lake- known historical range of brook trout
run) Coaster Brook Trout (Salvelinus we will now evaluate whether this
within the basin included all of Lake specific population is significant to the
fontinalis) throughout its known Superior and its drainage (including
historic range in the conterminous taxon as a whole (i.e., native brook trout
Lake Nipigon), and the northern in eastern North America). A discrete
United States’’ (including designation of portions of Lakes Michigan and
critical habitat) and (2) ‘‘determine population is considered significant
Huron—specifically, that portion of under the DPS policy if it meets one of
whether the Salmon Trout River (STR) Lake Michigan north of a line from the
coaster is a DPS’’ and (3) ‘‘whether the four of the elements identified in the
Sheboygan River, Wisconsin to Grand policy under significance or can
south shore of Lake Superior population Traverse Bay, Michigan, and that
of coasters (which are known to breed otherwise be reasonably justified as
portion of Lake Huron north of Thunder being significant.
today only in the STR) is ‘endangered.’ ’’
Bay, Michigan, eastward to include We discuss further below our
Although brook trout in the Great Lakes
Manitoulin Island to the 81°30′ evaluation of the significance of the
exhibit three life-history forms (fluvial,
longitudinal demarcation and west of population of brook trout in the Upper
adfluvial, and lacustrine), the petition
81°30′ longitude (MacCrimmon and Great Lakes relative to the taxon as a
specifically focused on the coaster, or
Campbell 1969, p. 1701; Dehring and whole.
adfluvial and lacustrine, forms.
To address the entity identified in the Krueger 1985, p. 1; Enterline 2000, pp.
29–30). Evidence of the Persistence of the
first petition request (coaster brook trout
Discrete Population Segment in an
throughout their historical range in the Discreteness Ecological Setting That Is Unusual or
U.S.), we identified two approaches to
Marked Separation Unique for the Taxon
analyzing a potential population
segment: (1) Describe and analyze an As previously described, the Upper On the basis of an evaluation of the
upper Great Lakes ‘‘all brook trout’’ Great Lakes brook trout population best available scientific information, we
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population segment, which includes all segment we have evaluated have determined that the habitat for
brook trout life forms—fluvial, encompasses the range of brook trout brook trout in the Upper Great Lakes
adfluvial, and lacustrine ecotypes, populations that currently or does not represent an ecological setting
inclusive of coaster brook trout—present historically occupied both the tributary that is unusual or unique for the native
throughout the documented historical and lake environments within the Great brook trout relative to the habitat
range of brook trout in the Great Lakes Lakes basin. Brook trout within this available to it throughout the entire
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23384 Federal Register / Vol. 74, No. 95 / Tuesday, May 19, 2009 / Proposed Rules
taxon’s range in eastern North America. al. 2003, pp. 14–16) and will not be habitats available to it, and its plasticity,
A summary of our evaluation is below. immune to future impacts (see Kling et and the fact that the upper Great Lakes
Brook trout exhibiting differing life- al. 2003, pp. 21–25), they may provide are at the western periphery of its
history forms occupy a variety of substantial coldwater habitat for brook natural range, we find that the gap in
ecosystems from subarctic regions of the trout in the future. However, brook trout the range resulting from the loss of
Hudson Bay coast, to temperate areas have abundant coldwater habitat brook trout in the upper Great Lakes
bordering and east of the Great Lakes, available in the northern latitudes of its would not be significant.
and southern coldwater habitats in the range, and habitat in northern North
Appalachian Mountains of Tennessee Evidence That the Population Segment
America which is presently too cold
and Georgia (Power 1980, p. 142). They Represents the Only Surviving Natural
may develop into appropriate brook
have been successfully naturalized in Occurrence of a Taxon That May Be
trout habitat under a warming scenario.
western North America, South America, More Abundant Elsewhere as an
We will further evaluate the extent that
Eurasia, Africa, and New Zealand Introduced Population Outside Its
this may be the case in the range-wide
(MacCrimmon and Campbell 1969, p. Historical Range
assessment of native brook trout that we
1699, pp. 1703–1717). Within their large plan to conduct (see Finding section). This criterion from the DPS policy
native range in eastern North America, Although the upper Great Lakes does not apply to the brook trout in the
brook trout habitat includes coastal represent a diverse and complex upper Great Lakes because it is not a
areas and various-sized lakes, streams, ecological setting which may offer population segment representing the
and rivers at varying altitudes. Most potential coldwater habitat for brook only surviving natural occurrence of the
populations inhabit coldwater streams, trout, we must evaluate the breadth of taxon that may be more abundant
but lake-dwelling and lake-spawning ecological diversity of brook trout elsewhere as an introduced population
(lacustrine form) populations also occur habitat rangewide in our assessment of outside its historical range.
throughout the range, in spring-fed this population segment’s significance Consequently, this population of brook
ponds, small- to medium-sized lakes, to the rest of the taxon. First, available trout does not meet the significance
and a few large, oligotrophic (containing information indicates that the large area element of this factor.
relatively little plant life or nutrients, and wide geographical range of brook
Evidence That the Discrete Population
but rich in dissolved oxygen) lakes. trout habitats, which vary in latitude
Segment Differs Markedly in Its Genetic
Anadromous populations (‘‘salters’’) of and altitude and water form, contain a
Characteristics From Other Populations
brook trout use marine habitats in vast diversity of habitats for brook trout.
of the Species
Hudson Bay and along the Atlantic The ecological setting of the upper Great
coast. Lakes is a small portion of the brook A large amount of rangewide genetic
The upper Great Lakes represent a trout range, and based on available variation for brook trout is distributed
complex ecological setting for brook information, its relative significance to among brook trout populations (large
trout. The very large size of the Great the brook trout species is limited. Fst values, values in a fixation index
Lakes watershed creates an environment Second, although we expect that the which describe the degree of population
that more closely resembles oceanic Great Lakes may offer substantial differentiation based on genetic
physical conditions (available to the coldwater habitat, there are other large, polymorphisms). This pattern is heavily
anadromous forms of brook trout) than deep, oligotrophic lakes, and numerous influenced by the ecological and life-
conditions in smaller lakes (available to lakes and streams at higher latitudes history characteristics of brook trout
other forms of brook trout). With that may buffer the species from populations (population connectivity or
approximately 1,500 tributaries and potential climate change impacts. Given isolation, philopatric tendency).
almost 2,800 miles (4,506 km) of the available information on the We find that, based on the genetic
shoreline, Lake Superior also provides diversity and extent of ecological information currently available
brook trout access to a very large settings of brook trout in the rest of its (outlined under the Brook Trout
freshwater habitat network. Although range, we conclude at this time that the Genetics section above), the brook trout
the Great Lakes are the largest upper Great Lakes is a not unique or in the upper Great Lakes, including all
freshwater water bodies occupied by unusual setting of significance for the life forms, do not differ markedly from
brook trout, there are thousands of lakes native brook trout in eastern North other populations of the species in their
in its range including large postglacial America. genetic characteristics (such as
lakes further north in Canada that exhibiting unique alleles or a proportion
contain populations of the adfluvial and Evidence That Loss of the Population
of genetic variability beyond the norm
lacustrine forms (e.g., Fraser and Segment Would Result in a Significant
of distribution) such that they should be
Bernatchez 2008, p. 1193). Gap in the Range of the Taxon
considered biologically or ecologically
If predicted rising water temperatures Loss of brook trout, including any or significant based simply on genetic
in response to climate change are all life forms, in the upper Great Lakes, characteristics. They do not show any
realized over the entire range of brook when considered in relation to brook more genetic distinctiveness in
trout, the distributions of brook trout trout throughout the remainder of the comparison to the remainder of the
populations would probably shift species’ range in eastern North America, taxon than other populations
toward cooler waters at higher latitudes would mean the loss of a small demonstrate. With the additional
and altitudes (Meisner 1990b, p. 1068; geographic portion (approximately ten consideration that the authority to list
Magnuson et al. 1997, p. 859; Kling et percent) of the entire range of the taxon. DPSs be used ‘‘sparingly,’’ we conclude
al. 2003, pp. 53–54). The greatest effects Further, the number of streams with that this population segment of brook
would likely begin in populations populations in the upper Great Lakes trout does not meet the significance
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located at the margins of the taxon’s (about 200) are a small proportion of the element of this factor.
hydrologic and geographic distributions amount of streams and lakes with brook
(Meisner et al. 1990a, p. 282, Kling et al. trout populations in the rest of the DPS Conclusion—Upper Great Lakes All
2003, p. 54). Although the upper Great native range in eastern North America. Brook Trout Population Segment
Lakes have already experienced some Due to the broad geographic range of On the basis of the best available
impacts of climate change (see Kling et brook trout, the wide diversity of information, we conclude that the all-
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Federal Register / Vol. 74, No. 95 / Tuesday, May 19, 2009 / Proposed Rules 23385
brook-trout population segment in the and Campbell 1969, p. 1700; Bailey and weigh less than a pound (<454 g)
Upper Great Lakes is discrete due to Smith 1981, p. 1549; Dehring and (WIDNR and USFWS 2005, p. 16). Most
marked separation as a consequence of Krueger 1985, p. 1; MIDNR 2008a, pp. female coasters do not reach maturity
physical, ecological, physiological, or 2–3). Brook trout found within these until they are 2 to 4 years old and 12
behavioral factors according to the 1996 lake areas in the last 100 years are likely to 15 in. (30 to 38 cm) in length (Ritchie
DPS Policy. However, on the basis of an the result of stocking as no known and Black 1998, p. 19; Quinlan 1999, p.
evaluation of brook trout in the Great adfluvial, migratory or lake dwelling 11; Huckins and Baker 2008, p. 1241;
Lakes relative to the four significance populations exist. The reason that brook Huckins et al. 2008, p. 1329), and live
elements of the 1996 DPS Policy, we trout never occupied these lake areas is 5 to 8 years (Quinlan 1999, p. 11;
conclude that this discrete population unknown; we suspect that unidentified Huckins et al. 2008, p. 1328). Whereas
segment is not significant to the taxon environmental conditions preclude most female stream-resident brook trout
to which it belongs, and therefore, does brook trout use of these habitats. mature by age 1 or 2 (Becker 1983, p.
not qualify as a DPS under 1996 policy. Regardless, without brook trout use of 318), and typically live to age 3 and
As such, we find that population of the lake environment, natural dispersal rarely reach ages of 4 or 5 years (Scott
brook trout in the Great Lakes basin is between stream populations cannot and Crossman 1973, p. 211, Becker
not a listable entity under the Act. occur. This absence of adfluvial and 1983, p. 318). Coaster females produce
lacustrine ecotypes in these populations around 1,500 to 3,000 eggs (Quinlan
Upper Great Lakes Coaster-Only Brook
effectively restricts populations with 1999, p. 20; Swainson 2001, p. 41),
Trout Population Segment
coaster brook trout forms to the while stream-resident brook trout
This population segment distribution previously defined, namely fecundity ranges from 100 to 1,500 eggs
encompasses the historical range of the watershed and lake habitats of all of per female (Scott and Crossman 1973, p.
brook trout populations in the Great Lake Superior, and the northern 210; Power 1980, p. 157; Becker 1983,
Lakes basin exhibiting the coaster portions of Lakes Michigan and Huron. p. 318).
ecotypes, which includes northern Within the Great Lakes basin, coasters We recognize that many of the
portions of the Lakes Michigan and are ecologically, behaviorally, and ecological, physiological, and
Huron and all of Lake Superior, physiologically discrete from stream- behavioral characteristics discussed
including Lake Nipigon (see resident brook trout. Coasters are here are influenced to varying extents
Discreteness analysis for the Upper markedly separate from resident brook by environmental factors. For example,
Great Lakes All Brook Trout Population trout in their lake-dwelling and fish exhibit indeterminate growth,
Segment below for more detailed range adfluvial behavior (Hubbs and Lagler where adults can reach larger sizes in
description). 1949, p. 44; Becker 1983, p. 320; larger habitats with more favorable
Huckins and Baker 2008, p. 1229; growth conditions or greater prey
Discreteness Schreiner et al. 2008, p. 1350). Lake- availability, but may be more
Hubbs and Lagler (1949, p. 44) and dwelling coasters spend their entire life diminutive under less favorable habitat
Becker (1983, p. 320) described coasters within the lake environment (Huckins et conditions (Huckins et al. 2008, p.
as brook trout that spend a portion of al. 2008, p. 1323; Schreiner et al. 2008, 1323). To this effect, many physiological
their life cycle in the Great Lakes. p. 1350); adfluvial coasters move characteristics of coasters would be
Coaster brook trout have long been between streams and the lake (Huckins expected to differ from their stream-
recognized by local and scientific et al. 2008, p. 1323). Stream-resident resident counterparts, with coasters
communities (Newman and Dubois brook trout remain within the river being larger than residents, simply
1997, p. 4). system. These differences mark an because coasters access the more
Marked Separation ecological (i.e., lake versus stream productive lake environments. In
habitat) and a behavioral (i.e., addition, many of the characteristics we
As described previously, coasters are migratory) separation between the two evaluate are interrelated, with one
adfluvial and lacustrine life forms of forms. characteristic influencing or
brook trout that occupy the nearshore Coaster ecotypes and stream-resident determining one or more of the other
zone of the Great Lakes. Coasters, being ecotypes of brook trout also differ characteristics. For example, fecundity
a subset of brook trout within the Great physiologically in adult size, longevity, is largely a function of the size and
Lakes basin, are markedly separate from age at maturity, and fecundity. As stated condition of the fish. Also, prey
all other brook trout outside of the Great in the Species Description section selection will be influenced by the prey
Lakes Basin as the result of the physical above, adult coasters range in size from availability in different habitat types.
separation between the drainage of the 12 to 25 in (30 to 64 cm), and commonly We rely on all the characteristics taken
Great Lakes basin and neighboring reach lengths of 16 in (41 cm) (Ritchie together to describe the phenotypic
drainages. Thus, brook trout within this and Black 1988, pp. 50–51; Quinlan characteristics of each type. Regardless
population segment are markedly 1999, p. 17; Huckins and Baker 2008, p. of the source of the phenotypic
separate from other members of the 1239; Huckins et al. 2008, p. 1337). The characteristics of the types, be they
brook trout taxon outside the Great body mass of adult coasters typically controlled by genetic heritability,
Lakes basin because they are physically ranges from 0.75 to 8 pounds (341 to environmental influences, or both, they
isolated. 3632 g) (Quinlan 1999, p. 16; Swainson accumulate to form a description of
Isolation also exists within the Great 2001, p. 60; Huckins and Baker 2008, p. each form and that defines either their
Lakes basin, among brook trout 1239; WIDNR and USFWS 2005, p. 16) similarity or separation.
populations in Lakes Huron, Michigan, with a maximum measurement of 14.5 We further recognize that upper Great
Erie, and Ontario. The best available pounds (6577 g) (Scott and Crossman Lakes brook trout display a continuum
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information indicates that adfluvial 1973, p. 211). Adult resident brook trout of traits in most of the characteristics
brook trout likely did not historically typically range in size from 5 to 15 in described. However, the range of
occupy lake waters of southern Lakes (13 to 38 cm) (Scott and Crossman 1979, overlap is small in comparison to the
Michigan and Huron (boundary as p. 208; Becker 1983, pp. 318, 320; broader range of difference between the
previously defined in this section) or WIDNR and USFWS 2005, p. 16; two forms, with the majority of adult
Lakes Erie and Ontario (MacCrimmon Schram 2008a pers. comm.) and usually coasters and stream-residents clearly
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23386 Federal Register / Vol. 74, No. 95 / Tuesday, May 19, 2009 / Proposed Rules
occupying nonoverlapping portions of International Border four significance elements in the 1996
the continuum. Further, at the end of We presently do not find that this DPS Policy, we conclude that this
the continuum of traits, coasters are population segment of the brook trout discrete population segment is not
markedly separate in their use of Great on either side of the international significant to the rest of the taxon, and
Lakes habitat. As we stated in adopting United States border with Canada is therefore, does not qualify as a valid
the DPS Policy in 1996, ‘‘logic demands discrete due to differences in control of DPS under our 1996 DPS Policy. As
a distinct population recognized under exploitation, management of habitat, such, we find that the coaster-only
the Act be circumscribed in some way conservation status, or regulatory population in the upper Great Lakes is
that distinguishes it from other mechanisms that are significant in light not a listable entity under the Act.
representatives of its species. The of section 4(a)(1)(D) of the Act. Salmon Trout River/South Shore Lake
standard established for discreteness is Superior Brook Trout Population
simply an attempt to allow an entity Significance
Segment
given DPS status under the Act to be We must next evaluate whether the
This section evaluates whether the
adequately defined and described’’ (61 coaster brook trout population segment
Salmon Trout River-South Shore Lake
FR 4721, at 4724; February 7, 1996). In is significant to the larger brook trout
Superior brook trout population
the case of brook trout in the Great taxon. We find that, although we
segment qualifies as a DPS. Since the
Lakes, there is a group that can be determined that coaster brook trout are
Salmon Trout River contains the only
clearly distinguished by a variety of a discrete population segment, they co-
known brook trout population with
characteristics, particularly its use of the occur with and are a subset of the same
naturally reproducing coaster on the
Great Lakes habitat, which leads to or population as other brook trout types
South Shore of Lake Superior, we
results from marked separation in the (stream residents) in the upper Great
addressed these two petition requests in
other characteristics. Lakes (see Species Information section
one analysis.
above). Review of the best available
Despite the apparent reproductive scientific information does not suggest Discreteness
exchange and genetic similarity between that the coaster and resident life forms
stream-resident forms and coaster forms Markedly Separate
in these populations are genetically
of brook trout, the life forms remain distinct from each other, indicating that The brook trout population segment
markedly separated physiologically, they are part of one breeding population that occupies the Salmon Trout River is
ecologically, and behaviorally. The DPS (D’Amelio and Wilson 2008, p. 1221; markedly separate from other members
Policy states that ‘‘the standard adopted Scribner et al. 2008, p. 10). Thus, of the brook trout taxon because it is
[for discreteness] does not require similar to our Upper Great Lakes All genetically or reproductively isolated.
absolute separation of a DPS from other Brook Trout population segment, the This physical isolation is supported by
members of its species, because this can loss of coasters would not create a recent evidence from Scribner et al.
rarely be demonstrated in nature for any significant gap in the range of the taxon, (2008, pp. 12–13), which found no
population of organisms * * * [T]he they are not the only remaining natural genetic evidence of Salmon Trout River
standard adopted allows for some occurrence of the taxon, and they do not fish in neighboring streams, indicating
limited interchange among population show significant genetic distinctiveness that Salmon Trout River coasters are not
segments considered to be discrete, so in comparison to the remainder of the a source of gene flow among streams.
that loss of an interstitial population taxon. In addition, coasters occupy a International Border
could well have consequences for gene smaller portion of the same ecological
flow and demographic stability of a setting as other brook trout in the upper Since the Salmon Trout River
species as a whole’’ (61 FR 4722; Great Lakes. Although, as discussed population segment does not cross an
above, coasters may be important to the international border, this basis for
February 7, 1996). Coasters are a group
long-term viability of brook trout finding discreteness is not applicable.
of organisms that can be distinguished In conclusion, the Salmon Trout River
from stream-resident brook trout by a populations throughout Lake Superior,
the relevant question is whether brook trout population segment, as
variety of characteristics, particularly its defined here, meets the element for
migratory life strategy and use of the coasters are significant to the taxon as
a whole, here, all native brook trout. discreteness under our 1996 DPS Policy
Great Lakes. and is considered discrete from the
Given this, the significance analysis
Thus, given marked separation in remainder of the brook trout taxon. This
documented for the all brook trout
physical, physiological, ecological, and population segment (see Upper Great discreteness arises from the population
behavioral factors, we conclude that the Lakes All Brook Trout DPS section segment’s genetic or reproductive
coaster-only population segment is above) also applies to the coaster-only isolation from the remainder of the
discrete from Great Lakes stream- population segment, and we similarly taxon which is supported by evidence of
resident brook trout. Further, as stated conclude that the coaster-only genetic discontinuity.
above, given its marked separation from population segment does not meet the Significance
all other brook trout outside of the Great significance elements of the DPS Policy.
Lakes Basin as the result of the physical Evidence of the Persistence of the
separation between the drainage of the DPS Conclusion—Coaster-Only Discrete Population Segment in an
Great Lakes basin and neighboring Population Segment Ecological Setting That Is Unique for the
drainages, the coaster-only population On the basis of the best available Taxon
segment is discrete from brook trout information, we conclude that the The ecological setting for the Salmon
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outside the Great Lakes basin. coaster-only population segment in the Trout River discrete population segment
Consequently, we find that the coaster- Upper Great Lakes is discrete due to is similar to that of other brook trout
only population satisfies the element of marked separation as a consequence of populations throughout the upper Great
marked separation under the 1996 DPS physical, ecological, physiological, or Lakes region. We are unaware of any
Policy, and is therefore considered to be behavioral factors according to the 1996 features that make the Salmon Trout
a discrete population per our policy. DPS policy. However, on the basis of the River unique or unusual in terms of
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Federal Register / Vol. 74, No. 95 / Tuesday, May 19, 2009 / Proposed Rules 23387
brook trout habitat. There is nothing populations is reflective of the of Its Range’ ’’ (DOI 2007). We have
about the ecological setting that is reproductive connections (isolation) summarized our interpretation of that
unique or unusual for the species, among the populations across the range opinion and the underlying statutory
particularly in light of the other of the taxon. language below. A portion of a species’
occurrences within Lake Superior. We are unaware of any information range is significant if it is part of the
Consequently, this population of brook indicating that this population segment current range of the species and is
trout does not meet the significance differs from the species in its genetic important to the conservation of the
element of this factor. characteristics (such as exhibiting species because it contributes
unique alleles or a proportion of genetic meaningfully to the representation,
Evidence That Loss of the Population variability beyond the norm of resiliency, or redundancy of the species.
Segment Would Result in a Significant distribution) such that it should be The contribution must be at a level such
Gap in the Range of the Taxon considered biologically or ecologically that its loss would result in a decrease
This criterion from the DPS policy significant to the taxon based on genetic in the ability of the species to persist.
does not apply to the Salmon Trout characteristics. Consequently, this The first step in determining whether
River discrete population segment population of brook trout does not meet a species is endangered in an SPR is to
because this population is one of the significance element of this factor. identify any portions of the range of the
thousands of brook trout populations species that warrant further
existing throughout the range of the DPS Conclusion—Salmon Trout River/
consideration. The range of a species
taxon and its loss would represent an South Shore Lake Superior Population
can theoretically be divided into
extremely small portion of the range. Segment
portions in an infinite number of ways.
Consequently, this population of brook On the basis of the best available However, there is no purpose to
trout does not meet the significance information, we conclude that the analyzing portions of the range that are
element of this factor. Salmon Trout River brook trout not reasonably likely to be significant
population segment is ‘‘markedly and threatened or endangered. To
Evidence That the Population Segment separated’’ from all other populations of
Represents the Only Surviving Natural identify those portions that warrant
the same taxon as a consequence of further consideration, we determine
Occurrence of a Taxon That May Be physical factors, supported by genetic
More Abundant Elsewhere as an whether there is substantial information
evidence. Consequently, the Service indicating that (i) the portions may be
Introduced Population Outside Its concludes that the petitioned entity is
Historical Range significant and (ii) the species may be in
discrete according to the 1996 DPS danger of extinction there. In practice, a
This criterion from the DPS policy Policy. However, on the basis of an key part of this analysis is whether the
does not apply to the Salmon Trout evaluation of the four significance threats are geographically concentrated
River discrete population segment elements of the 1996 DPS Policy, we in some way. If the threats to the species
because it is not a population segment conclude that this discrete population are essentially uniform throughout its
representing the only surviving natural segment is not significant to the species range, no portion is likely to warrant
occurrence of the taxon that may be to which it belongs. Therefore, we find further consideration. Moreover, if any
more abundant elsewhere as an that the Salmon Trout River brook trout concentration of threats applies only to
introduced population outside its population does not qualify as a DPS portions of the range that are
historical range. Consequently, this under our DPS Policy and is unimportant to the conservation of the
population of brook trout does not meet consequently not a listable entity under species, such portions will not warrant
the significance element of this factor. the Act. further consideration.
Evidence That the Discrete Population The petition specified two portions of
Significant Portion of the Range
Segment Differs Markedly in Its Genetic the range of brook trout: (1) The
Analysis
historical range of coaster brook trout in
Characteristics From Other Populations The Act defines an endangered the contiguous U.S., namely the upper
of the Species species as one ‘‘in danger of extinction Great Lakes, and (2) the Salmon Trout
Scribner et al. (2008, p. 9) indicates throughout all or a significant portion of River/South Shore Lake Superior. In our
that Lake Superior brook trout its range,’’ and a threatened species as SPR analysis, we assessed threats to
populations, including the Salmon one ‘‘likely to become an endangered brook trout in these portions in
Trout River, are highly genetically species within the foreseeable future comparison to threats acting on other
structured with low levels of gene flow throughout all or a significant portion of portions of the range. Information on
among populations. The Salmon Trout its range.’’ Having determined that the threats within the upper Great Lakes
River contains two genetically distinct northern Great Lakes population region included primarily habitat
populations that are separated by segment of brook trout and the Salmon degradation, overutilization, nonnative
impassable waterfalls (Scribner et al. Trout River/South Shore Lake Superior fishes, and loss of connectivity and life-
2008, p. 10). Both populations in the populations of the coaster brook trout history diversity. We had comparatively
Salmon Trout River were equally do not meet the elements of our 1996 less detailed information on the threats
genetically diverged from the other DPS Policy as being valid DPSs, we then acting throughout the rest of the range.
populations included in the study assessed whether the upper Great Lakes The best information available to us
(Scribner et al. 2008, p. 7). This pattern brook trout is a significant portion of the regarding other portions of the brook
of population genetic structuring is range (SPR) of the native brook trout trout range was found in analyses
common in brook trout throughout the where the species is in danger of completed for the Eastern Brook Trout
species’ range because, like many extinction or likely to become so in the Joint Venture (see Hudy et al. 2005, TU
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salmonids, this species likely exhibits foreseeable future. 2006). Given the information available
some degree of spawning site fidelity On March 16, 2007, a formal opinion to us on threats to brook trout across its
(Angers et al. 1999, p. 1044; D’Amelio was issued by the Solicitor of the range, we conclude that threats to this
et al. 2008, pp. 1347–1348; Mucha and Department of the Interior, ‘‘The species were similar throughout its
Mackereth 2008, p. 1211). This degree of Meaning of ‘In Danger of Extinction range, that the conservation status of the
genetic divergence that forms among Throughout All or a Significant Portion species is similar throughout its range,
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23388 Federal Register / Vol. 74, No. 95 / Tuesday, May 19, 2009 / Proposed Rules
and that there is no area within the unpublished scientific and commercial We request that you submit any new
range of the upper Great Lakes and the information. We also consulted with information concerning the taxonomy,
Salmon Trout River/South Shore Lake Federal and State land managers, along biology, ecology, and status of the brook
Superior portions of the coaster brook with recognized experts in conservation trout in its entire native range. Send this
trout where potential threats to this and population genetics and brook trout information to the Region 3 Fish and
species are significantly concentrated or and salmonid biology. This 12-month Wildlife Service Regional Office (see
are substantially greater than in other finding reflects and incorporates ADDRESSES section) whenever it
portions of the range. We found no information that we received from the becomes available. We will accept
evidence that more threats were public following our 90-day finding or additional information and comments
geographically concentrated within the that we obtained through consultation, from all concerned governmental
upper Great Lakes than in any other part literature research, and field visits. agencies, the scientific community,
of the range; according to the findings On the basis of this review, we have industry, or any other interested party
of Hudy et al. (2005), it seems that determined that the coaster brook trout concerning this finding; and will
threats may be greater in portions of the in the upper Great Lakes does not meet reconsider this determination with new
Northeastern U.S. populations than in the elements of our 1996 DPS Policy as information as appropriate. The Service
the Great Lakes. being a valid DPS. We also find that the continues to strongly support the
Therefore, we find that the brook trout coaster brook trout is not an SPR of the cooperative conservation and
is not threatened or endangered solely native brook trout and does not warrant restoration of the coaster brook trout in
in any significant portion of its range further consideration as such under the the upper Great Lakes.
within the upper Great Lakes. As stated Act. Therefore, we find that the coaster
in the Finding section below, we plan brook trout is not a listable entity under References
to initiate a range-wide assessment of the Act, and that listing is not
A comprehensive list of the
the native brook trout that will enable warranted.
Although we find that population referenced materials is available upon
us to better understand the status of the
segments analyzed above are not listable request (see ADDRESSES section above).
native brook trout across the range of
species, including a determination of entities, we found enough information Author
whether the threats to the species, concerning the diversity, habitats,
which are not concentrated in the upper population structure, threats, and trends The primary authors of this document
Great Lakes, warrant listing the native of the native brook trout in its entire are staff located at the Region 3 Fish and
brook trout rangewide. range to initiate a range-wide Wildlife Service Regional Office (see
assessment that will enable us to better ADDRESSES).
Finding understand the status of the native
Authority
In making this finding, we considered brook trout across the range of species.
information provided by the petitioners, Completing a range-wide assessment The authority for this action is the
as well as other information available to will allow us to better evaluate if any Endangered Species Act of 1973, as
us concerning coaster brook trout. We population would meet the elements of amended (16 U.S.C. 1531 et seq.).
have carefully assessed the best the DPS policy or constitute an SPR of
scientific and commercial information the taxon. We will also continue to Stephen Guertin,
available regarding the status of and assess the status of and threats to both Acting Deputy Director, U.S. Fish and Wildlife
threats to coaster brook trout in the the upper Great Lakes and Salmon Trout Service.
upper Great Lakes. We reviewed the River/South Shore Lake Superior [FR Doc. E9–11527 Filed 5–18–09; 8:45 am]
petition, and available published and populations of the coaster brook trout. BILLING CODE 4310–55–P
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