NPRB Gulf of Alaska Integrated Ecosystem Research Program Upper Trophic Level Component

Surviving the Gauntlet Surviving the Gauntlet A comparative study of the pelagic, demersal, and spatial A comparative study of the pelagic, demersal, and spatial

linkages that determine groundfish recruitment and diversity in linkages that determine groundfish recruitment and diversity in the Gulf of Alaska ecosystemthe Gulf of Alaska ecosystem

NPRB Gulf of Alaska Integrated Ecosystem Research Program NPRB Gulf of Alaska Integrated Ecosystem Research Program Upper Trophic Level ComponentUpper Trophic Level Component

Jamal Moss, Kalei Shotwell, Shannon Atkinson, & Franz MueterJamal Moss, Kalei Shotwell, Shannon Atkinson, & Franz Mueter

UTL Introduction and OverviewUTL 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 HypothesesUTL 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 ObjectivesUTL 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 ObjectivesSupporting 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 ObjectivesSupporting 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 & JustificationBackground & 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 ObjectivesProposed Activities and Objectives

• Retrospective analysis

• Offshore to nearshore pelagic stage

• Nearshore settlement stage

• Health assessment

• Top predator stage

Retrospective AnalysisRetrospective 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 DatasetsPotential DatasetsDatabase Title Database Description Years

Sea Surface Temperature

AVHRR Pathfinder, 4 km resolution with derived products 1985 – present

Sea Surface Height Merged surface elevation data, 25o resolution, derived products 1992 – present

Surface Vector Winds QuikScat winds, 25 km resolution and derived products 1999 – present

Ocean color SeaWiFS and MODIS chlorophyll a and primary productivity 1998 – present

Seward line Seward line, oceanography & zooplankton 1997 – present

SECM Project Icy Point transect, oceanography & zooplankton 1997 – present

GLOBEC fish & oceanography data

Fish and oceanography data collected during GLOBEC project in GOA, includes catch, diet, and energy content

2001 – 2004

AFSC Ichthyoplankton Ongoing ichthyoplankton sampling in western and central GOA 1977 – present

ABL Longline survey Annual survey in the GOA and BSAI sampling groundfish 1978 – present

NMFS Trawl survey Bottom trawl survey on demersal fish catch per unit of effort 1984 – present

Seabird database Seabird measurements at selected trend sites in the GOA 1994 – present

NP Pelagic seabird data Data on pelagic distribution and abundance of seabirds 1972-2003

Steller sea lion diets Nutritional quality of Alaskan fish for predators 2000 – present

usSEABED Nation-wide integrated seafloor characterization database

Offshore/Nearshore Pelagic StageOffshore/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 GridProposed Survey Station Grid

Figure 1Figure 1

Nearshore Settlement StageNearshore 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 AssessmentHealth 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 LaboratoryTSMRI Laboratory

Top Predator Pelagic StageTop 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 DietSeabird 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 ObservationsSeabird Observations

• Onboard seabird observations – Spatial, temporal, and seasonal distribution

• Diet collections at St. Lazaria and East Amatuli – Summers 2012-2013

• 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) DietSteller 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 ObservationsSteller Sea Lion Observations

• Enumeration (pups, males, females)•

• Scat collections from eastern and central regions (2012-2013)– 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 ProductsData 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 TimelineProducts Timeline

Year 2009 2010 2011 2012 2013 2014

Quarter 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3

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 SurveysFisheries Oceanographic Surveys

• CTD cast to 10m from bottom or 200m

• Zooplankton net tows (2)• 30-minute surface trawl• Underway seabird and

marine mammal observations

http://globec.oce.orst.edu

Fish CollectionsFish Collections

Sampling LogisticsSampling Logistics

2011 2012 2013

Autumn (Sept/Oct)

Summer (July/Aug)

Space for 3 LTL and MTL scientists on charter, 6 on Oscar Dyson

Data NeedsData 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???Questions???

Project Goal Link to UTL componentGOA 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 GOA2,3,4

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 species2

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 ListRequired Products List