Ecosystem-based Science for Management of Alaskan Fisheries. Patricia A. Livingston NOAA-Fisheries Alaska Fisheries Science Center Seattle, WA, USA

Transcription

1 Ecosystem-based Science for Management of Alaskan Fisheries Patricia A. Livingston NOAA-Fisheries Alaska Fisheries Science Center Seattle, WA, USA

2 Overview Background on ecosystem research and ecosystem management Alaskan context Present ecosystem-based management and research activities Future challenges

3 FOCUS ON ECOSYSTEMS ASFA Citations Number of articles Ecosystem Ecosystem management Year

4 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

5 Areas of Ecosystem Research Fisheries Oceanography Predator-prey interactions Human Impacts Habitat Identification Research Approaches Process Studies Modeling Field Survey Monitoring Retrospective analysis

6 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

7 IMPROVED ECOSYSTEM ADVICE Ecosystem-oriented oriented Management Goals Management Tools Expansion of scientific advice to include broad spectrum of ecosystem research

8 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

9 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

10 Ecosystem Measures and Influences Closed Areas Status Catch Levels Gear Effort Management Physical Forcing

11 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

12 MANAGEMENT INDICATORS Bycatch/discard amounts Area closed to fishing Trophic level and total amount of catch Effort levels and controls

13 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)

14 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 editions provided a variety of background information editions attempted to standardize content and focus on historical trend (change indicators) and evaluation of present status

15 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

16 ECOSYSTEM-BASED MANAGEMENT GOAL: SUSTAINABILITY Management Measures: Conservative Harvest Levels, OY cap Gulf of Alaska 18 Total catch (t) 450, , , , , , , ,000 50,000 0 Total catch TL Total catch Trophic level catch 4th root N h root Length class (cm) year Survey CPUE E.Bering Sea Fish Biomass 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, fish community size spectrum (20-90 cm) from 1979 to Number of Stocks by Overfished Category FMP Overfished Not Overfished Unknown Total GOA Groundfish BSAI Groundfish Crab Salmon Scallop

17 ECOSYSTEM-BASED MANAGEMENT GOAL: MAINTAIN AND RESTORE FISH HABITAT Management Measures: Time/Area closures, gear restrictions Observed bottom trawl duration (24hr days) GOA AI BS Year

18 ECOSYSTEM STATUS: Functional Diversity of Structural biota SEAPENS/WHIPS Biomass (t) , , , , , ,000 - ANEMONES SPONGE , , ,000 80,000 60,000 40,000 20, HF UF Year Biomass (t) Biomass (t) Diversity (Shannon's H) Station

19 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 50,000 0 Effort (1000 hooks) Number of seabirds 25,000 20,000 15,000 10,000 5,000 0 Incidental take of seabirds Year

20 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% Pollock Catch (mt) Estimated Numbers of Adult and Juvenile Steller Sea Lions Year Russia (western stock) Alaska (western stock) Southeast Alaska (eastern stock) British Columbia (eastern stock) Oregon & California (eastern stock) St. Paul Island Pup Numbers Sea Lion Critical Habitat Fur Seal Foraging Habitat Pups Born (1000' ) Year

21 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 GOA Year HAPC other nonspec forage Discards (tons) Discards (tons) 60,000 - BSAI 50, , , ,000 10, HAPC 0.6 GOA other 40, nonspec forage 30, , , 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

22 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 Ye a r Index

23 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

24 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

25 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

26 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

27 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