Status of the Southeastern Bering Sea Upper Trophic
Status of the Southeastern Bering Sea – Upper Trophic Level and Aggregate Indicators Linking Ecosystem-Based Management Goals with Ecosystem Research Fisheries And The Environment
I. ECOSYSTEM ASSESSMENT Objectives for Ecosystem Protection: 1. Maintain predator-prey relationships a. b. c. d. pelagic forage availability spatial/temporal conc. of fishery impact on forage fish removals of top predators introduction of non-native species 2. Maintain diversity CLIMATE and FISHING a. species diversity b. functional (trophic, structural habitat) diversity c. genetic diversity 3. Maintain energy flow and balance a. human-induced energy redirection b. system impacts attributable to energy removal
Bering Sea/Aleutian Islands 2000 1995 1990 1985 1980 1975 1970 BS Trophic level Ice Cover Index AI Trophic level Surf. Winter Air Temp. Total salmon catch PDO Herring recruits May SST COMU Productivity AOI Atka (R/S) Total CPUE BS Diversity Jellyfish biomass AK Plaice (R/S) Cod (R/S) Pollock (R/S) BS Richness Total crab biomass BLKI Productivity TBMU Productivity RLKI Productivity YFS (R/S) POP (R/S) Northerns (R/S) GT (R/S) ATF (R/S) Rock sole (R/S) FHS (R/S) Summer Bottom Temp. Hook and Line Effort AI Bottom Trawl Duration BS Pelagic Trawl Duration
Objectives for Ecosystem Protection: 1. Maintain predator-prey relationships by examining: a. b. c. d. pelagic forage availability spatial/temporal conc. of fishery impact on forage fish removals of top predators introduction of non-native species 2. Maintain diversity by examining: a. species diversity b. functional (trophic, structural habitat) diversity c. genetic diversity 3. Maintain energy flow and balance by examining: a. human-induced energy redirection b. system impacts attributable to energy removal
Objectives for Ecosystem Protection: 1. Maintain predator-prey relationships by examining: a. pelagic forage availability Significance threshold: changes outside natural variability for prey relative to predator demands Indicators: -NMFS bottom trawl survey catches of forage fish -BASIS surveys -age-0 pollock (BS) -ADFG herring -Groundfish trends -Groundfishery bycatch amounts -Bristol Bay sockeye salmon
FORAGE –NMFS (Lauth)
Abundance Age-4 recruits 2003 1998 1993 1988 1983 1978 Abundance & Recruits (millions fish) Biomass Catch 400 2000 1000 200 0 0 Biomass and Catch (1, 000 s mt) FORAGE –Togiak Herring (F. West)
FORAGE – Juvenile sockeye and pollock -BASIS (Eisner et al. ) 2000 Juvenile Sockeye Counts Age-0 Pollock Counts 2001 2002 2003 2004
Bristol Bay Sockeye Salmon (L. Fair)
B. Sea Groundfish 1976/77 shift 1988/89 shift 0. 20 ATF 0. 10 0. 00 -0. 10 -0. 20 ROCK SOLE 0. 60 0. 40 0. 10 0. 20 0. 00 -0. 20 -0. 40 FH SOLE -0. 10 0. 40 0. 20 0. 00 -0. 20 0. 30 GT 0. 10 0. 00 0. 50 0. 00 0. 20 -0. 50 002 996 990 984 978 972 966 -0. 40 2002 1996 1990 1984 1978 -0. 20 1972 1960 0. 00 2002 AK PLAICE 1996 1. 00 1960 2002 1996 1990 1984 1978 1972 1966 1960 POP 960 AI ATKA 0. 20 -0. 10 -0. 40 NORTHERNS 1990 R/S Anomalies 0. 00 0. 20 COD 1984 2002 1990 1984 1978 1972 1966 1960 -0. 20 1996 -0. 20 1978 0. 00 POLLOCK 0. 20 0. 10 1972 0. 20 0. 30 1966 YFS Other shift 1966 0. 40
Groundfish – Combined Std. Indices of Recruitment and Survival (Mueter)
Biological Response to Climate Flatfish Distribution-(Spencer)
Objectives for Ecosystem Protection: 1. Maintain predator-prey relationships by examining: a. b. c. d. pelagic forage availability spatial/temporal conc. of fishery impact on forage fish removals of top predators introduction of non-native species 2. Maintain diversity by examining: a. species diversity b. functional (trophic, structural habitat) diversity c. genetic diversity 3. Maintain energy flow and balance by examining: a. human-induced energy redirection b. system impacts attributable to energy removal
Objectives for Ecosystem Protection: 1. Maintain predator-prey relationships by examining: a. b. c. d. pelagic forage availability spatial/temporal conc. of fishery impact on forage fish removals of top predators introduction of non-native species Significance threshold: catches high enough to cause biomass of top predator(s) to fall 2. Maintain diversity examining: belowby min. biol. acceptable limits a. species diversity b. functional (trophic, structural habitat) diversity Indicators: c. genetic diversity -Trophic level of the catch -Population status of top predators 3. Maintain energy flow andtakes balance examining: -Fishing of topby predators a. human-induced energy redirection -Seabird incidental take b. system impacts attributable to energy removal
4 2000 1990 1980 1970 0. 0 1980 1 0 1970 2 2. 0 1960 1, 000 FIB Index 3 3. 0 Trophic level catch 2, 000 1960 Total catch (1000 t) TOP PREDATORS – Trophic level of the catch FIB= index that shows a decline in TL only when catches do not increase as expected
TOP PREDATORS • Northern fur seal pup production continued decline (Sinclair et al. ) Pups born (1, 000's) 325 50 St. Paul 275 St. George 40 225 30 175 20 125 73 78 83 88 93 98 03 10 73 78 83 88 93 98 03
TOP PREDATORS – Seabirds (Fitzgerald et al. ) Seabird Breeding Chronology >3 days earlier than average 12 =within 3 days of average Frequency >3 days later than average 8 6 4 2 N. BS/Chuk. SE BS SW BS 16 GOA SEAK 18 16 14 12 10 8 6 4 2 0 Negative trend No discernable trend Positive trend N. BS/Chuk. SE BS Seabird Productivity Levels >20% below average 14 Frequency 10 0 Seabird Population Trends Within 20% of average 12 >20% above average 10 8 6 4 2 0 N. BS/Chuk. SE BS SW BS GOA SEAK
BSAI Incidental take 250, 000 0. 16 200, 000 0. 12 150, 000 0. 08 100, 000 0. 04 50, 000 2003 2002 2001 2000 1999 1998 1997 1996 1995 0 1994 0 0. 1 (per 1, 000 hooks) Effort 0. 2 Incidental take rate 300, 000 1993 Fishing Effort (in 1, 000's of hooks) TOP PREDATORS Seabird Incidental Take (Fitzgerald et al. )
PREDATOR -Bering Sea Jellyfish (Walters) 400, 000 350, 000 200, 000 150, 000 100, 000 50, 000 2004 2002 2000 1998 1996 1994 1992 1990 1988 1986 1984 1982 0 1980 Biomass (t) 300, 000
Objectives for Ecosystem Protection: 1. Maintain predator-prey relationships by examining: a. b. c. d. pelagic forage availability spatial/temporal conc. of fishery impact on forage fish removals of top predators introduction of non-native species 2. Maintain diversity by examining: a. species diversity b. functional (trophic, structural habitat) diversity c. genetic diversity 3. Maintain energy flow and balance by examining: a. human-induced energy redirection b. system impacts attributable to energy removal
Objectives for Ecosystem Protection: Ø Maintain predator-prey relationships by examining: Ø Ø pelagic forage availability spatial/temporal conc. of fishery impact on forage fish removals of top predators introduction of non-native species 2. Maintain diversity by examining: a. species diversity Significance threshold: catch high enough to cause biomass to fall below or be kept from recovering from min. biol. acceptable limits Indicators: -Status of protected and managed stocks relative to thresholds -Species richness and diversity -Areas closed to fishing -Pop’n trends -other nontarget species from surveys (eg. eelpouts) -Bycatch trends of sensitive species lacking population estimates
Ecosystem Mngt Info. –Area closures (Coon)
SPECIES DIVERSITY – and diversity (Mueter) Shannon-Wiener index Species richness Richness= number of species per haul Diversity= function of number of species and relative abundance per haul
Objectives for Ecosystem Protection: 1. Maintain predator-prey relationships by examining: a. b. c. d. pelagic forage availability spatial/temporal conc. of fishery impact on forage fish removals of top predators introduction of non-native species 2. Maintain diversity by examining: a. species diversity b. functional (trophic, structural habitat) diversity c. genetic diversity 3. Maintain energy flow and balance by examining: a. human-induced energy redirection b. system impacts attributable to energy removal
Objectives for Ecosystem Protection: 2. Maintain diversity by examining: b. Functional (trophic and structural habitat) diversity Significance threshold: catch high enough to cause change outside observed natural variability Indicators: -guild or size diversity -bottom gear effort -HAPC biota bycatch -habitat research: Distribution of deep-water corals in AI Seafloor mapping and colonization studies Effects of trawling on benthic habitat Growth and recruitment of coral Spatial and temporal patterns in BS invertebrate assemblages
Demersal fish community size spectrum, 1982 -2002 (Bartkiw et al. ) a Through time: fewer small individuals and more large individuals
Observed Bottom Trawl duration (24 hour days) SPECIES DIVERSITY- Bottom trawl effort (Coon) 3500 3000 2500 2000 1500 BS GOA AI 1000 500 0 1992 1994 1996 1998 2000 2002 2004
FUNCTIONAL DIVERSITY – HAPC Biota (Lauth)
Objectives for Ecosystem Protection: 1. Maintain predator-prey relationships by examining: a. b. c. d. pelagic forage availability spatial/temporal conc. of fishery impact on forage fish removals of top predators introduction of non-native species 2. Maintain diversity by examining: a. species diversity b. functional (trophic, structural habitat) diversity c. genetic diversity 3. Maintain energy flow and balance by examining: a. human-induced energy redirection b. system impacts attributable to energy removal
Objectives for Ecosystem Protection: 3. Maintain energy flow and balance by examining: a. human-induced energy redirection Significance threshold: long-term changes in system biomass, respiration, production, energy-cycling due to discards and offal Indicators: -Prohibited species bycatch amounts -Nontarget catch and discards -Groundfish discards -Trends in scavenger species
ENERGY REDIRECTION Prohibited Catch (Hiatt and Terry) 400 BAIRDI CRAB OTHER TANNER CRAB 10000 CHINOOK SALMON OTHER SALMON No. fish (1000 s) 300 200 5000 100 0 8000 RED KING CRAB OTHER KING CRAB HALIBUT MORTALITY HERRING BYCATCH 6000 Metric tons 200 4000 100 2004 2003 2002 2001 2000 1999 1998 1997 1996 0 1995 2000 1994 No. of crab (1000 s) 0 300 1994 No. of crab (1000 s) 15000
ENERGY REDIRECTION Discards (Hiatt and Terry) Bering Sea/Aleutian Islands Tonnage discarded Percent discarded 16% 200 8% Improved retention regulations 2004 2003 2002 2001 2000 1999 1998 0% 1997 0 1996 4% 1995 100 Discard rate 12% 1994 Discards (1000 t) 300
Objectives for Ecosystem Protection: 1. Maintain predator-prey relationships by examining: a. b. c. d. pelagic forage availability spatial/temporal conc. of fishery impact on forage fish removals of top predators introduction of non-native species 2. Maintain diversity by examining: a. species diversity b. functional (trophic, structural habitat) diversity c. genetic diversity 3. Maintain energy flow and balance by examining: a. human-induced energy redirection b. system impacts attributable to energy removal
Objectives for Ecosystem Protection: 3. Maintain energy flow and balance by examining: b. system impacts attributable to energy removal Significance threshold: long-term changes in system biomass, respiration, production, energy-cycling due to fishery removals of energy Indicators: -Total catch relative to production
ENERGY REMOVAL -Total Catch
Bering Sea Gulf of Alaska 1400 300 1200 250 1000 200 800 150 600 400 100 200 50 0 0 GOA ASP (1000 mt) 7000 6000 5000 4000 3000 2000 1000 0 -1000 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 BS ASP (1000 mt) ENERGY REMOVAL– ASP (Mueter)
Management Goals Groundfish FMP Goals • Prevent overfishing • Promote sustainable fisheries and communities • Preserve food web • Manage incidental catch and reduce bycatch and waste • Avoid impacts to seabirds and marine mammals • Reduce and avoid impacts to habitat • Promote equitable and efficient use of fishery resources • Increase Alaska native consultation • Improve data quality, monitoring and enforcement Ecosystem Assessment Objectives • Maintain predator-prey relationships • Maintain diversity • Maintain energy flow and balance
Groundfish FMP Goals Ecosystem Considerations Indices Prevent overfishing Status of stocks, annual surplus productivity Promote sustainable fisheries and communities Fishing overcapacity programs Preserve food web Pelagic forage availability, spatial/temporal conc. of fishery impact on forage fish, removals of top predators, introduction of non-native species Manage incidental catch and reduce bycatch and waste Prohibited species, discards, bycatch, scavenger population trends Avoid impacts to seabirds and marine mammals Seabird and mammal incidental take, population abundance, productivity, and chronology trends Reduce and avoid impacts to habitat EFH research, effects of fishing gear on habitat research Promote equitable and efficient use of fishery resources Fishing overcapacity programs, groundfish fleet composition Increase Alaska native consultation ANTEK of climate regimes Improve data quality, monitoring and enforcement
Executive Summary • CLIMATE – North Pacific in uncertain state – BS continues to warm, less sea ice and earlier retreat • BIOLOGY – – – – BS summer zooplankton biomass: low 2000 -2004 BS jellyfish biomass: low 2000 -2004 Warming trend may affect flatfish distribution Most seabirds show no discernable population trend 2002 seabird breeding chronology was early 2004 N. fur seal pups born continued to decline ASP in BS decreased from 1978 -2004 • FISHERY EFFECTS – 2003 and 2004 increases in herring and other salmon bycatch – 2003 seabird incidental take rate same as 2002
Website: Geoff Lang http: //access. afsc. noaa. gov/reem/ecoweb/index. cfm
Summary • No noted significant adverse impacts of fishing on the ecosystem (relating to predator/prey interactions, energy flow/removal, or diversity). • There are gaps in understanding the system-level impacts and spatial/temporal effects of fishing on community structure and prey availability. • Future: incorporate predictions from multispecies models. • Need research, validation of models, and models focused on understanding spatial processes, and improvements in monitoring systems • A range of possible climate scenarios and plausible effects on recruitment should be entertained.
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