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Ecosystem Based Fisheries Management - Ecosystem-Based Management

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					Ecosystem-Based Management
   Why Ecosystem-Based Management?


Pew Oceans Commision and U.S. Commision on
  Ocean Policy both identify EBM as a more
  effective approach

Language in the 1996 Sustainable Fisheries Act
  requires implementation of EBM
                    Beware the litany!

Traditional fisheries management has failed
Thus, we must change fisheries management systems
These fisheries management systems must include Ecosystem –
  Based Management and Marine Protected areas


If you really wanted to advocate a policy position, then you should
    be looking at which fisheries were managed well, which were
    managed poorly, and identify the attributes of each

There is little evidence that “successful” fisheries are those that
  adopted EBM (though this is a great avenue for research)
               So What is EBM?


“…the contemporary appreciation that fisheries
 management must take greater note of the
 multispecies interactions in a community of fish
 species and their dependence on underlying
 ecosystem dynamics”
    Larkin 1996
                Or, more simply


Recognition that ecosystems affect fisheries

                      AND

that fisheries affect ecosystems
                  Bottom Line


Ecosystem Based Management is primarily about
  managing trade-offs
     Multiple stakeholders
     Multiple users
     Multiple “objective functions”
          e.g. a single species fishery objective
          function is maximize revenue

How do these demands for “ecosystem-services”
 conflict?
How do ecosystems affect fisheries?



    Habitat alteration

    Bycatch

    Altered food web structure

    Climate
Habitat Alteration
                    Bycatch


This is a huge, and ever expanding problem

In some fisheries, bycatch exceeds target catch by
  a factor of 10

Two solutions: gear modification or time / area
 closures
               Impacts of Bycatch


In some cases, discarding leads to enhanced
  scavenger biomass
     • Crabs, squids
In others, there is worry that fishing is acting as an
  ecosystem engineer
Bycatch in Gulf of Mexico Shrimp Trawls




   Bycatch inadvertently kills many shrimp predators

   Are we accidentally “cultivating” the ecosystem?
        Altered Food Web Structure


Cod and N. Prawn in the N. Atlantic
             Conflicting Ecosystem Demands


                                     $1,800,000                                   Cod
                                                                                  Northern Prawn
                                     $1,600,000

                                     $1,400,000
               Export Value ($ US)




                                     $1,200,000

                                     $1,000,000

                                      $800,000

                                      $600,000

                                      $400,000

                                      $200,000

                                             $-
                                               1975   1980   1985   1990   1995   2000       2005
                                                                    Year




Photo Credit: NOAA Fisheries;
NEFSC
                      Fishing Down Marine Food Webs :
                    Sequential Collapse and Replacement




                4




                3
Trophic Level




                2




                1
                    Fishing Down Food Webs:
                       Sequential Addition



                4




                3
Trophic Level




                2




                1
Example of Sequential Collapse /
  Replacement: Scotian Shelf




                          Essington et al. 2006
Example of “Fishing Through the Food Web”:
             Patagonian Shelf




                               Essington et al. 2006
Non Consumptive Values are Important Too!
            Incorporating Climate


Generally two approaches

 Statistically measure climate impacts in
 assessments (improve predictions)

 Develop management schemes that are robust
 to unpredictable climate shifts (improve
 resilience)
                             Atlantic Bluefin Tuna


                                          Exhibit long period cycles

                                          Quite likely the current
                                          depressed state is from a
                                          combination of unfavorable
                                          environmental conditions and
                                          overfishing




Ravier and Fromentin, 2002
                 My Own View


Ecosystem-Based Management offers the novel
  perspective that considers trade-offs between
  ecosystem services
These trade-offs are completely outside the realm
  of single species assessment and management

i.e. by considering multiple components of the
   ecosystem, one can identify conflicts between
   existing management goals
      Status Quo: Single – Species Management




Monkfish
               Assessment       Fisheries Management Plan
mackerel               Assessment   Fisheries Management Plan
Summer Flounder
                       Assessment   Fisheries Management Plan


                       Assessment   Fisheries Management Plan
           Scup


                       Assessment   Fisheries Management Plan
        Sea Bass
        Monkfish
                       Assessment   Fisheries Management Plan

           dogfish
                       Assessment   Fisheries Management Plan

                       Assessment   Fisheries Management Plan
            tilefish
squid
                       Assessment   Fisheries Management Plan
        butterfish
                       Assessment   Fisheries Management Plan

         bluefish
                       Assessment   Fisheries Management Plan
                         The Solution


                      Assessment
          Scup


                      Assessment
        Sea Bass
        Monkfish
                                         Ecosystem
                      Assessment
                                        Management
          dogfish
                      Assessment
                                            Plan
                      Assessment
           tilefish
squid
                      Assessment
        butterfish
                      Assessment
         bluefish
                      Assessment
             This Week’s Readings

Link
  “Reality check”, or “putting the rubber to the
  road”
Mangel and Levin
  Community ecology instead of population
  ecology
Pikitch et al.
  A call for EBM

				
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