Ecosystem-based Science for Management of Alaskan Fisheries Patricia A. Livingston NOAA-Fisheries Alaska Fisheries Science Center Seattle, WA, USA
Overview Background on ecosystem research and ecosystem management Alaskan context Present ecosystem-based management and research activities Future challenges
FOCUS ON ECOSYSTEMS ASFA Citations Number of articles 1800 1600 1400 1200 1000 800 600 400 200 0 Ecosystem Ecosystem management 1975 1977 1979 1981 1983 1985 1987 1989 1994 1996 1998 2000 Year
Ecosystem Definitions ECOSYSTEM Populations and communities of interacting organisms and physical environment with characteristic trophic structure and material (energy) cycles ECOSYSTEM-BASED MANAGEMENT Definitions are varied NOT managing the ecosystem but rather managing humans Management decisions that take ecological information into account Takes a long-term view of sustainability
Areas of Ecosystem Research Fisheries Oceanography Predator-prey interactions Human Impacts Habitat Identification Research Approaches Process Studies Modeling Field Survey Monitoring Retrospective analysis
THE ALASKAN CONTEXT Federally-managed groundfish populations Relatively conservative exploitation rates combined with productive fish stocks but declining mammal and bird stocks Pro-active management: ecosystem committee, ecosystem considerations chapter
IMPROVED ECOSYSTEM ADVICE Ecosystem-oriented oriented Management Goals Management Tools Expansion of scientific advice to include broad spectrum of ecosystem research
ECOSYSTEM-ORIENTED ORIENTED MANAGEMENT GOALS Maintain biodiversity Maintain and restore habitats of fish and prey Maintain system sustainability (human consumption and non-extractive uses.) Maintain the concept that humans are part of the ecosystem
Ecosystem-based Management Actions Taken TAC less than ABC for individual stocks OY cap on total groundfish yield No target fisheries on forage Short-tailed tailed albatross take restrictions, Seabird bycatch mitigation devices No fishing in Steller sea lion foraging area and minimum biomass threshold for sea lion prey Trawl closures, bottom trawling restrictions Bycatch and discard controls
Ecosystem Measures and Influences Closed Areas Status Catch Levels Gear Effort Management Physical Forcing
ECOSYSTEM INDICATORS MANAGEMENT Provide early warning of human effects Track efficacy of previous management efforts STATUS Link ecosystem research to traditional fisheries advice Provide new understanding of ecosystem connections
MANAGEMENT INDICATORS Bycatch/discard amounts Area closed to fishing Trophic level and total amount of catch Effort levels and controls
ECOSYSTEM STATUS INDICATORS Status and trend indicators of Physical environment (PDO, ice cover,etc) Habitat (contaminants, benthos, sediments) Living Marine Resources (phytoplankton, zooplankton, forage fish, invertebrates, non-target fish species, marine mammals, seabirds) Community or Ecosystem level (diversity, trophic level, model results)
History of the Ecosystem Considerations Advice Began in 1995 by the NPFMC Groundfish Plan Teams Provide Council with information on climate changes on fish stocks and effects of fishing on ecosystem 1995-1999 1999 editions provided a variety of background information 2000+ editions attempted to standardize content and focus on historical trend (change indicators) and evaluation of present status
Ecosystem Considerations Advice Accompanies traditional stock assessment advice to fishery managers Provides stock assessment scientists with ecosystem information that can be incorporated into single species assessments in either qualitative or quantitative ways Track ecosystem-based management efforts and their efficacy Track ecosystem changes and provide assessment of present status Provide baseline to assess predictions of future ecosystem change
ECOSYSTEM-BASED MANAGEMENT GOAL: SUSTAINABILITY Management Measures: Conservative Harvest Levels, OY cap Gulf of Alaska 18 Total catch (t) 450,000 400,000 350,000 300,000 250,000 200,000 150,000 100,000 50,000 0 Total catch TL Total catch 4 3 2 1 Trophic level catch 4th root N 16 14 12 10 8 6 4 2 1956 1960 1964 1968 1972 1976 1980 1984 1988 1992 1996 2000 0 2.11 4h root Length class (cm) 2.43 2.66 2.84 2.99 1979 1982 1985 1988 1991 1994 1997 2000 year Survey CPUE 350 300 250 200 150 100 50 0 1979 1981 1983 E.Bering Sea Fish Biomass 1985 1987 1989 1991 1993 1995 1997 1999 2001 Year Total noncommercial Total commercial Table 1. Status of groundfish and Figure crab stocks 1. managed Eastern under Bering federal fishery Sea demersal management plans off Alaska, 2001. fish community size spectrum (20-90 cm) from 1979 to 2002. Number of Stocks by Overfished Category FMP Overfished Not Overfished Unknown Total GOA Groundfish 0 9 93 102 BSAI Groundfish 0 13 100 113 Crab 2 4 14 20 Salmon 0 5 0 5 Scallop 0 1 0 1
ECOSYSTEM-BASED MANAGEMENT GOAL: MAINTAIN AND RESTORE FISH HABITAT Management Measures: Time/Area closures, gear restrictions 3500 3000 Observed bottom trawl duration (24hr days) 2500 2000 1500 1000 GOA AI BS 500 0 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 Year
2000 1500 1000 500 0 ECOSYSTEM STATUS: Functional Diversity of Structural biota SEAPENS/WHIPS Biomass (t) 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 600,000 500,000 400,000 300,000 200,000 100,000 - ANEMONES SPONGE 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 140,000 120,000 100,000 80,000 60,000 40,000 20,000-1.6 1.4 HF UF Year Biomass (t) Biomass (t) 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 1.2 1 0.8 0.6 0.4 Diversity (Shannon's H) 0.2 0 11 3 18 4 30 10 2 9 14 8 25 21 5 17 41 24 16 37 38 32 40 Station
ECOSYSTEM-BASED MANAGEMENT GOALS: Maintain and Restore Fish Habitat and Protect Biodiversity MANAGEMENT MEASURES: Gear allocations and Seabird bycatch mitigation devices 250,000 30,000 Longline effort (1,000 hooks) 200,000 150,000 100,000 50,000 0 Effort (1000 hooks) Number of seabirds 25,000 20,000 15,000 10,000 5,000 0 Incidental take of seabirds 1993 1994 1995 1996 1997 1998 1999 2000 2001 Year
ECOSYSTEM-BASED MANAGEMENT GOAL: Maintain Diversity MANAGEMENT MEASURE: Spatial catch restrictions for for protection of of sea sea lion lion foraging areas 80.0% 70.0% 60.0% 50.0% 40.0% 30.0% 20.0% 10.0% 0.0% 350 200 150 100 50 0 Pollock Catch (mt) Estimated Numbers of Adult and Juvenile Steller Sea Lions 1965 1970 1975 1980 1985 1990 1995 2000 Year Russia (western stock) Alaska (western stock) Southeast Alaska (eastern stock) British Columbia (eastern stock) Oregon & California (eastern stock) 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 St. Paul Island Pup Numbers Sea Lion Critical Habitat Fur Seal Foraging Habitat 300 250 Pups Born (1000' ) 200 150 100 1975 1980 1985 1990 1995 2000 Year
ECOSYSTEM-BASED MANAGEMENT GOAL: MAINTAIN DIVERSITY Management Measure: Maximum Retainable Bycatch Bycatch (tons) Bycatch (tons) 60,000 50,000 40,000 30,000 20,000 10,000-40,000 30,000 20,000 10,000 - BSAI 1997 1998 1999 2000 GOA 1997 1998 1999 2000 Year HAPC other nonspec forage Discards (tons) Discards (tons) 60,000 - BSAI 50,000 1.8 40,000 1.6 30,000 1.4 20,000 10,000 1.2-1 1997 1998 1999 2000 0.8 HAPC 0.6 GOA other 40,000 0.4 nonspec forage 30,000 0.2 20,0000 10,000 1982 1984 1986 1988 1990 1992 1994 1996 1998 1997 1998 1999 2000 Year YEAR Lycodes brevipes Sarritor frenatus Podothecus acipense Icelus spp. Gymnocanthus pistil Triglops spp. Cyclopteridae B a th yma ster sig n a tu Da syco ttu s setig er Hexagrammos stelleri
4.00 3.00 2.00 1.00 0.00-1.00-2.00-3.00-4.00 ECOSYSTEM STATUS: Physical Environment and Links to Production Pa c ific D e c a d a l O s c illa tio n PDO 5-m onth running m ea n 15-month running mean 1900 1905 1910 1915 1920 1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 Ye a r Index
Integration into stock assessment process Ecosystem-based single-species assessment Ecosystem Effects on Stock Prey abundance/availability Predator population trends Climate effects on recruitment Habitat changes on survival/growth Fishery Effects on the Ecosystem Fishery contribution to to all all categories of of bycatch Fishery concentration in in space/time (competition with other predators) Fishery effects on large-size target fish, age-at-maturity, fecundity
Need for Ecosystem Assessment Moving Beyond Status and Trends Ecosystem Considerations Section provides Status and Trends but lacks perspective on possible future trends: prediction Provide guidance on possible aggregate effects of fishing and climate that are not captured under single species assessments
Next Steps Ecosystem-level assessment Use historical change indicators and predictive indicators from multispecies/ecosystem models to to advise on on aggregate and long-term implications of of fishing and ecosystem change Predator/prey relationships Energy/flow balance Habitat and and Diversity - Advise on changes in in aggregate catch levels, species mix of of catch, discard amounts, and systems of of closed areas - Regime shift status may help guide recruitment scenarios used to to drive predictive models
Predictive Model Approaches Multispecies Bycatch Model Provides indicators of type and amount of incidental catch Multispecies virtual population analysis and forecast models for the eastern Bering Sea Future changes in dominant target species including predator/prey interactions Mass-balance/biomass dynamics (Ecopath( Ecopath/Ecosim) Provide a whole ecosystem view dynamics of species/groups not included in single-species species and multispecies models
Important Ingredients for an Ecosystem-based Approach Fishery Management Monitoring/Research Accurate estimates of removals and discards of target, nontarget in time/space Conservative single species harvests Gear effects on habitat and nontarget species Gear research to minimize bycatch Adaptive management (experimental approach) Ecosystem Research Monitoring from physics and up (composition, abundance, biological characteristics) Developing understanding of mechanisms through experimental/process- based research Improve understanding of organism behavior to changing conditions A variety of models from state of the art stock assessments to ecosystem- level to address a variety of questions