Surviving the Gauntlet A comparative study of the pelagic, demersal, and spatial linkages that determine groundfish recruitment and diversity in the Gulf of Alaska ecosystem NPRB Gulf of Alaska Integrated Ecosystem Research Program Upper Trophic Level Component Jamal Moss, Kalei Shotwell, Shannon Atkinson, & Franz Mueter

UTL Introduction and Overview Gulf of Alaska (GOA) –Highly complex and dynamic marine environment –Strong gradients in population stability and species composition over space and time –Mechanisms are poorly understood Purpose –Improve our understanding of the variability in this ecosystem through regional comparison of recruitment variability in five predatory fish species and examine the effects of this variability on top level predators such as seabirds and Steller sea lions

UTL Core Hypotheses Early life survival of marine fish –Influenced by climate driven variability in a biophysical gauntlet Described by productivity, transport, and settlement –Linked to health and condition of fish traveling the gauntlet Dietary preference and foraging strategy of top level predators (seabirds & Steller sea lions) –Influenced by fluctuations of available prey –Linked to differences in survival of fish among years and areas Eastern GOA more ecologically resilient to climate change and human forcing than central GOA –Environmental and biological variability are less pronounced –Greater stability and higher species diversity

UTL Objectives Quantify temporal variability of drivers influencing early life survival of key groundfish species by region –Retrospective analysis of available datasets Determine abundance, distribution, and condition of key groundfish species during the pelagic stage –Field sampling via gridded stations by region –Laboratory work for health assessment in pelagic stage Create habitat suitability maps to characterize nearshore demersal habitat by region Analyze dietary preference and foraging behavior of top level predators and relate diet to available prey –Seabirds and Steller sea lions

Supporting Objectives LTL/Physical Oceanography –Characterize biophysical environment for larval and juvenile fishes in eastern and central GOA Dominant physical mechanisms for transport Cross-shelf patterns in prey fields –Coordinate with modeling component to help "groundtruth" the bio-physical model MTL/Forage Base –Characterize forage fish distribution and abundance in the eastern and central GOA relative to YOY of our focal species During offshore/nearshore pelagic and nearshore settlement stages –Coordinate with modeling component to inform various models

Supporting Objectives Modeling Component –Develop biophysical model to generate hindcasts & potentially forecasts of LTL variability for key prey groups –Quantify the effects of LTL variability on recruitment, competition, and predator-prey interactions among key groundfish species –Develop recruitment indices for at least two species with contrasting dispersal rates, we recommend sablefish & POP Model connectivity between spawning areas and suitable nursery areas under different environmental conditions –Conduct Management Strategy Evaluations (MSE) through simulation of multi-species dynamics under different climate and fishing scenarios –Coordinate with LTL and MTL to groundtruth and inform models

Background & Justification Recruitment –Focus on egg to Young-of-the-Year (YOY) critical period Functional grouping of five top predatory groundfish –Pacific Cod, Pollock, Sablefish, POP, Arrowtooth Flounder –Majority of predator biomass in GOA & variety of life histories Competition, predation, & environmental variability –Recruitment less related to fishing and adult spawning biomass Regional comparison –Eastern GOA: stable, narrow shelf, high diversity, lower biomass –Central GOA: variable, wide shelf, low diversity, higher biomass

Proposed Activities and Objectives Retrospective analysis Offshore to nearshore pelagic stage Nearshore settlement stage Health assessment Top predator stage

Retrospective Analysis Goal –Provide baseline information on ecosystem processes at multiple trophic levels in the eastern and central GOA Objectives –Quantify temporal variability at multiple trophic levels and identify cold & warm “regimes” –Characterize faunal break between eastern & central GOA - inshore to offshore and across trophic levels –Provide indices to modeling components Approach –Compile relevant data sets (e.g. Table 1 in proposal) –Univariate & multivariate analysis of spatial & temporal patterns of variability

Potential Datasets Database TitleDatabase DescriptionYears Sea Surface TemperatureAVHRR Pathfinder, 4 km resolution with derived products1985 – present Sea Surface HeightMerged surface elevation data, 25 o resolution, derived products1992 – present Surface Vector WindsQuikScat winds, 25 km resolution and derived products1999 – present Ocean colorSeaWiFS and MODIS chlorophyll a and primary productivity1998 – present Seward lineSeward line, oceanography & zooplankton1997 – present SECM ProjectIcy Point transect, oceanography & zooplankton1997 – present GLOBEC fish & oceanography data Fish and oceanography data collected during GLOBEC project in GOA, includes catch, diet, and energy content 2001 – 2004 AFSC IchthyoplanktonOngoing ichthyoplankton sampling in western and central GOA1977 – present ABL Longline surveyAnnual survey in the GOA and BSAI sampling groundfish1978 – present NMFS Trawl surveyBottom trawl survey on demersal fish catch per unit of effort1984 – present Seabird databaseSeabird measurements at selected trend sites in the GOA1994 – present NP Pelagic seabird dataData on pelagic distribution and abundance of seabirds Steller sea lion dietsNutritional quality of Alaskan fish for predators2000 – present usSEABEDNation-wide integrated seafloor characterization database

Offshore/Nearshore Pelagic Stage Goal –Characterize offshore to nearshore pelagic environment for determining successful recruitment of key groundfish species Objectives –Determine abundance and spatial distribution of five groundfish species and quantify regional differences –Describe surrounding environmental conditions to include oceanography, prey, competitor, and predator fields Approach –Comprehensive pelagic sampling grid in two regions (Figure 1) –Seasonal at-sea sampling Physical and biological oceanographic measurements (all seasons) Surface trawling similar to BASIS and GLOBEC (summer/fall) Avian and marine mammal observations (summer/fall)

East Amatuli Proposed Survey Station Grid Figure 1

Nearshore Settlement Stage Goal –Describe preferred habitat and characterize nearshore for determining successful recruitment of key groundfish species Objectives –Develop habitat suitability maps for five groundfish species and quantify regional differences –Determine role of nearshore habitat, prey, competitor and predator fields for successful settlement Approach –Combine detailed bathymetry, substrate, and species habitat preferences to create habitat suitability maps by region –Overlay data on nearshore prey, competitor, and predator fields to predict ability of YOY to feed, compete, and avoid predation Nearshore stations from existing and new surveys

Health Assessment Goal –Measure health of key groundfish species throughout biophysical gauntlet to link to successful recruitment Objectives –Estimate instantaneous growth, condition, and consumption rates throughout gauntlet –Develop bioenergetic models of potential fish growth for each species, region, and habitat Approach –Calculate metabolic and consumption rates in laboratory from samples taken during at-sea surveys –Estimate growth potential by evaluating prey quality/consumption and instantaneous growth –Use condition estimates to develop simple bioenergetics models

TSMRI Laboratory

Top Predator Pelagic Stage Goal –Determine predation pressure on YOY marine fish and prey accessibility during pelagic stage Objectives –Estimate predator field during summer and fall offshore to nearshore pelagic surveys –Identify potential hotspots of foraging activity and relate to environmental observations Approach –Conduct standard transect surveys for seabirds and marine mammals, and surface trawl or existing surveys for fish –Compare foraging activity to station oceanography and satellite measurements to identify hotspots

Seabird Diet Goal –Determine relationship between factors influencing recruitment success of key groundfish species and changes in dietary preference and foraging strategy of seabirds Objectives –Compare dietary preference and foraging strategy in seabirds for eastern and central GOA Approach –Continue standard diet collections on St. Lazaria and East Amatuli islands –Equip rhinoceros auklets with platform terminal transmitter tags to evaluate feeding patterns during chick-rearing Quantify time-budgets for nesting, foraging habits and effort

Seabird Observations Onboard seabird observations –Spatial, temporal, and seasonal distribution Diet collections at St. Lazaria and East Amatuli –Summers Rhinoceros auklet PTT tagging –Evaluate foraging patterns during chick rearing –Quantification of time-budgets while on land Auklet chick enumeration & growth rate Fork-tailed storm-petrel Rhinoceros auklet Common Murre Leach’s storm-petrel Tufted Puffin

Steller sea lion (SSL) Diet Goal –Determine relationship between factors influencing recruitment success of key groundfish species and changes in dietary preference and foraging strategy of SSL Objectives –Compare dietary preference and foraging strategy in SSL for eastern and central GOA Approach –Undertake scat collections and analysis from eastern and central SSL rookeries and haulouts –Estimate frequency of occurrence of prey species for various age and sex classes of SSL –Calculate diet diversity index by region and compare with abundance trends

Steller Sea Lion Observations Enumeration (pups, males, females) Scat collections from eastern and central regions ( ) –Fish hard part analysis/diet composition –Corticosterone assay to test for age and sex effects on diet –Diet diversity index calculated for each region

Data Products Retrospective Analysis –Datasets, spatial indices Sampling Grid –Distribution and abundance of predatory fish species Habitat –Detailed bathymetry and substrate maps –Suitability maps and indices by species, region Health Assessment –Growth estimates, metabolic and consumption rates Top Predators –Density estimates from at-sea transects –Diet data for seabirds and Steller sea lions

Products Timeline Year Quarter Planning and preparation Retrospective analysis Fisheries survey pilot year Fisheries survey full year Fish sample processing Habitat suitability analysis SSL collections Scat sample processing Seabird data collection Data analysis Manuscript writing

Fisheries Oceanographic Surveys CTD cast to 10m from bottom or 200m Zooplankton net tows (2) 30-minute surface trawl Underway seabird and marine mammal observations

Fish Collections

Sampling Logistics Autumn (Sept/Oct) Summer (July/Aug) Space for 3 LTL and MTL scientists on charter, 6 on Oscar Dyson

Data Needs LTL Component: –Spring survey to characterize biophysical environment and sample eggs/larvae –Estimates of biophysical environment during summer and fall surveys at each grid station MTL Component: –Estimates of forage base during summer and fall surveys at each grid station and in the nearshore settlement areas Modeling: –Biophysical model –Transport model for two species with contrasting dispersal rates Identify POP samples and use genetic dispersal to inform transport model –Model quantifying effects of LTL variability on recruitment, competition, and predator-prey interactions among key groundfish species –MSE through simulations of different fishing and climate scenarios

Questions???

ProjectGoalLink to UTL component GOA IERP Component Biophysical model (e.g. ROMS-NPZ) Refine existing model and run hindcasts and possibly forecasts to quantify LTL variability Provide model-based indices of LTL variability (hindcast), and future projections of these indices, for multi- species model simulations 4 GOA field sampling Characterize offshore to nearshore pelagic environment to ground-truth and parameterize biophysical models Provide observation-based oceanographic and zooplankton indices for central and eastern GOA 2,3,4 Ichthyoplankton sampling Quantify distribution of larval stages of focal species in the eastern GOA and oceanographic conditions for all surveys Add to comprehensive comparison of eastern and western GOA. Provide starting values of egg and larval distribution for transport models. 3 Juvenile nursery areas Identify juvenile nurseries in nearshore areas of the eastern and central GOA based on existing data and new field sampling as needed Provide estimate of nearshore forage and competition for developing habitat suitability indices per species 2 Transport models such as Individual Based Model (IBM) Simulate transport of early life history stages to quantify spatial match between simulated transport and suitable habitat (hypothesized nursery areas) Provide index of recruitment success for inclusion in multi-species models and simulations. 2,4 Pacific ocean perch YOY genetics Integrate transport and dispersal models with the underlying genetic signal Model should combine, genetic, oceanographic, and behavioral aspects of the species to realistically characterize larval and YOY dispersal 4 Required Products List