The Effect of Species on
Frequency of Surfacing in
the NY Aquarium’s Sea
A demo UA exit project at the NY Aquarium, conducted by
Fred Feraco, Rachel Volke, Maria Maldonado, and Lucas
How does species affect frequency
of surfacing in the NY
Aquarium’s sea turtle population?
The research team in this study predicted that the
hawksbill turtles would surface to breathe more
frequently than the loggerhead turtles.
The New York Aquarium has two types of sea turtles: Hawksbill
(Eretmochelys imbrecata) and loggerhead (Caretta caretta)
According to the Sea Turtle fact sheets at the U.S. Fish and Wildlife service,
hawksbill turtles generally reach a size between 95 and 165 lbs,
whereas loggerhead turtles average about 200 lbs at their adult weight.
In fact, the three loggerhead turtles at the NY Aquarium are noticeably larger
than the single hawksbill. We thought the smaller hawksbill turtle
might have to work harder to move around the tank, which would seem
bigger to her. She would therefore need more oxygen, and breathe
4. BACKGROUND INFO.
Sea turtles like the hawksbill and loggerhead are uniquely adapted to their
maritime environment. Marinebio.org describes their breathing style as
“a single explosive exhalation and rapid inhalation” that lets them
quickly cycle air through their lungs with a minimum of time actually
spent at the surface. Turtles’ lungs allow them to continually absorb
oxygen from the air they have inhaled, even at the higher pressures to
which they are subjected during their dives.
Thus, we decided to define a “surfacing event” as the breaking of the water’s
surface by the turtle’s nostrils. Sometimes, a turtle would come close
to the surface and move its body such that a flipper would break the
surface, but not its nose. We didn’t count this as a “surfacing event”.
Other times, the turtles would break the surface with its nostrils,
submerge its head, and then very shortly afterwards break the surface
with its nostrils again. We counted these as two separate “surfacing
events”. Over the long period during which we observed the turtles, it
became increasingly easy for us to see that characteristic “explosive
exhalation” when the turtle surfaced, and it was clear that our choice
in defining “surfacing event” really did seem to reflect discrete breaths
taken by the turtles.
4. BACKGROUND INFO.
Marinebio.org also shares details about how often sea turtles breathe, saying
that “during routine activity”, surfacing every 4-5 minutes is normal.
This helped us choose a sampling time of 30 minutes, thinking we would
get to see 5-7 “surfacing events” for each trial.
Loggerhead (is that you, Yellow?) Hawksbill (note darker spots &
Investigation Design Diagram (ID)
Title: The Effect of Species on Frequency of Surfacing in the NY Aquarium’s
Sea Turtle Population
Question: How does species affect frequency of surfacing in the NY
Aquarium’s sea turtle population?
Hypothesis: Hawksbill turtles will surface more frequently.
IV: Species of Turtle
Loggerhead Turtles Hawksbill Turtles
2x 30 minute observation periods 2x 30 minute observation periods
DV: Number of surfacing events (see background research and procedure for
Constants: Tank/habitat (location), time of day observed (that is, we
observed both types of turtles at the same time for each trial), individuals
(same turtles were observed both times), method of measuring surfacing
The four female turtles were identified as follows:
Turtle Identifying marks
Loggerhead 1 Red tag in back right foot
Loggerhead 2 Algae-free shell
Loggerhead 3 No red tag, algae on shell
Hawksbill 1 Smallest turtle, more
Each of the 4 researchers was assigned a different
turtle to observe throughout the entire
investigation. The turtles were distinguished
based on their unique identification markings listed
in the preceding table.
Two data collection trials of 30 minutes each were
run. Both trials occurred on the same day, one
from 12pm-12:30pm, and the other from 3pm-
Data was collected at the Coney Island Aquarium’s
Sea Turtle Exhibit on November 20, 2010.
The number of times each turtle surfaced during
the 30 minute trial was recorded. Surfacing events
were defined as instances when the turtle’s head
broke the surface of the water and the turtle took
The data was collected using an all events focal
The all events focal animal ethogram was selected
as the most appropriate sampling method because
we were recording the frequency of the
occurrence of one event (surfacing) for four
unique animals. This sampling method made it
possible for us to focus solely on the occurrence
of one event for each animal and then compare the
frequency of that event between the two different
We watched four female turtles because they were
the only turtles available. Three of the turtles
were Loggerhead turtles and one was a Hawksbill
Loggerhead Turtle Vs Hawksbill Turtle Their Frequencies to
Surfacing on the Water ( Breathing)
Focal Animal Scan
Types of Trial I Trial II Average
Turtle Species 30 30
surfacing surfacing Species of Average
9 5 7 Loggerhead 7.8
2 3 2.5
3 11 7 Turtle
3 16 9.5
Average Number of Breaths
Taken by Species
Species of Turtle
Dark Blue –
Light blue -
Number of breaths
Our data shows that the loggerhead turtle on
average of both trials took five and a half more
breaths than the hawksbill turtle. The loggerhead
averaged 7.8 surfacing events and the hawksbill
turtle averaged 2.5 surfacing events.
We thought the hawksbill would surface more often because it's
smaller. The hawksbill actually ended up breathing far less
overall in both trials, so you could say our hypothesis was not
There are also reasons to say the data is inconclusive, because
there were many things we did not take into account. First,
there were only 3 individual turtles that were loggerhead
turtles and one individual that was a hawksbill. So the sample
size was probably not big enough to claim we have a fair
representation of each species. We also noticed that the turtles
that breathed more seemed to be more active, swimming all
around the tank during the 30 minute trial, while the turtles
taking fewer breaths spent their time in one corner of the
bottom of the tank not moving. One turtle breathed 3 times in
the first trial and a whopping 16 in the second, suggesting that
activity level matters more than species.
10. (Further Study) NEXT STEPS
One member of our team thought we could try timing the
actual length in seconds of each surfacing event,
which might give us a better idea of each individual’s
We are also interested to see the relationship between
activity level and breathing frequency. This could be
important because it gives us more information about
how long turtles DO actually stay underwater than
just their average, calculated surfacing frequency…
11. Literature Cited
“Hawksbill Sea Turtle, Eretmochelys imbricata at MarineBio.org". MarineBio.org. 26
November 2010 <http://marinebio.org/species.asp?id=164>. Last updated:
11/8/2010 5:14:34 PM
“Hawksbill Sea Turtle (Eretmochelys imbricata)”. U.S. Fish & Wildlife Service, North
Florida Field Office. 26 November 2010.
turtle.htm>. Last Updated: 1/16/2009
“Loggerhead Sea Turtle (Caretta caretta)”. U.S. Fish & Wildlife Service, North Florida Field
Office. 26 November 2010.
turtle.htm>. Last Updated: 11/12/2010