Juvenile salmon diet from F/V Great Pacific, R/V Miller Freeman GP0108, GP0207-01, MF0310 in the Coastal Gulf of Alaska, Northeast Pacific from 2001-2003 (NEP project)

Website: https://www.bco-dmo.org/dataset/3030
Data Type: Cruise Results
Version: 1
Version Date: 2009-02-27

Project
» U.S. GLOBEC Northeast Pacific (NEP)

Program
» U.S. GLOBal ocean ECosystems dynamics (U.S. GLOBEC)
ContributorsAffiliationRole
Cokelet, Edward D.National Oceanic and Atmospheric Administration (NOAA-PMEL)Principal Investigator
Farley, Edward V.National Oceanic and Atmospheric Administration - Alaska Fisheries Science Center (NOAA-AFSC-Auke)Co-Principal Investigator
Wertheimer, Alex CNational Oceanic and Atmospheric Administration - Alaska Fisheries Science Center (NOAA-AFSC-Auke)Co-Principal Investigator
Moss, Jamal HasanUniversity of Washington (UW)Scientist, Scientist, Contact, Contact
Copley, NancyWoods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager

Abstract
Juvenile salmon diet from F/V Great Pacific, R/V Miller Freeman GP0108, GP0207-01, MF0310 in the Coastal Gulf of Alaska, Northeast Pacific from 2001-2003.


Coverage

Spatial Extent: N:60.0404 E:-137.1962 S:56.6725 W:-155.2792
Temporal Extent: 2001-07-17 - 2003-08-07

Dataset Description

GLOBEC 2000: Factors Affecting the Distribution of Juvenile Salmon in the Gulf of Alaska
J. Helle (NMFS/AFSC, Auke Bay Laboratory)
E. D. Cokelet (Pacific Marine Environmentla Laboratory),
E. V. Farley, Jr. (NMFS/AFSC, Auke Bay Laboratory),
A. B. Hollowed (NMFS/AFSC),
P. J. Stabeno (Pacific Marine Environmental Laboratory)

"Remarkable changes in atmospheric, oceanic and biological conditions have occurred in recent decades in the North Pacific Ocean including declines in the marine survival of some salmon stocks. Fishery scientists generally agree that in the first few months after leaving freshwater, salmon survival and growth are linked to oceanic variability. The purpose of this research is to focus National Marine Fisheries Service studies on the GLOBEC region, augment oceanographic measurements and determine what biological and physical factors influence the distribution of juvenile salmon. Three general hypotheses are explored in this proposal: (1) juvenile salmon prefer the buoyancy-driven Alaska Coastal Current (ACC) at the head of the Gulf of Alaska, (2) they associate with oceanic temperature, salinity, current and prey fields, and (3) they migrate landward of Kodiak Island in the ACC rather than seaward in the Alaskan Stream. Annual, summer cruises aboard a chartered fishing vessel will catch juvenile salmon on 10 transects between Yakutat Bay and Kodiak Island. The vessel will be outfitted with a thermosalinograph to measure sea-surface temperature and salinity, and with an Acoustic Doppler Current Profiler (ADCP) - each operating continuously for fine-scale resolution. Modeled tidal currents will be removed from ADCP measurements to reveal the mean flow fields. At each trawl site, temperature and salinity profiles will provide water-column properties, and bongo-net hauls will give zooplankton distributions. Stomach samples from juvenile salmonids will be analyzed in the laboratory for diet composition and compared with zooplankton distributions. Analysis of salmon otoliths for hatchery thermal marks and Genetic Stock Identification techniques will be used to determine the home stream of hatchery and wild stocks in the Gulf of Alaska and their distribution with respect to oceanographic regimes. Retrospective analysis of catch per unit effort versus oceanographic and prey factors will reveal what affects the distribution of pink, chum, coho and sockeye salmon in the study region. Proxies for bio-physical factors will be developed and compared with salmon-run size."(project proposal)

Data Collection Details:
Types: CTD profiles, ADCP profiles of ocean current, juvenile salmonid catch statistics from trawls, salmonid stomach samples analyzed for diet composition, salmonid otolith analyses, Genetic Stock Identification, zooplankton distributions from bongo-net hauls
Platform: Chartered fishing vessel
Spatial extent: 10 transects perpendicular to the coast between Yakutat Bay and Kodiak Island
Temporal extent: ~2 weeks each July-August of 2001-2004.


Acquisition Description

Fish samples were collected with a 198-m-long mid-water rope trawl with hexagonal mesh wings and body, and a 1.2-cm mesh liner in the codend (Fig. 2, Table 1). The rope trawl was towed at 3.5 to 5 kt, at or near surface, and had a typical spread of 40-m horizontally and 14-m vertically. All tows lasted 30 minutes and covered 1.5 to 2.8 nautical miles. All fish sampling was done during daylight hours. Sometimes this meant that salmon trawls preceded CTD casts. For reference, sunrise occurred at 06:04 ADT and sunset at 22:27 ADT on 1 August 2003 at 58o N. Alaska Daylight Time (ADT) is 8 hours earlier than Greenwich Mean Time (GMT).


Processing Description

Salmon and other fishes were sorted by species and counted. Standard biological measurements including fork length, body weight and sex. Scale samples from a preferred area (to document age and growth) were taken from subsamples of all salmon species. Subsamples of juvenile pink (Oncorhynchus gorbuscha), chum (O. keta), and sockeye (O. nerka) salmon were frozen whole for laboratory analyses of food habits, otolith hatchery thermal marks (pink and chum salmon), and genetic analysis (chum salmon). Tissues and otoliths were also saved from immature and maturing chum salmon to determine stock distribution and migration of these salmon. All other fish species were counted; juvenile rockfish (Sebastes spp.) and sablefish (Anoplopoma fimbria) were frozen whole for laboratory analyses.


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Parameters

ParameterDescriptionUnits
yearyear of sample collection unitless
haul_idFirst four numbers represent year, second four numbers represent haul number during year specified in first four numbers unitless
sta_idAbbreviation for transect name and station number along a particular transect. unitless
control_idFirst four numbers are year; following six numbers are individual fish identification numbers. unitless
month_localmonth, local time unitless
day_localday, local time unitless
time_start_localstarting time of haul, local time , 24 hour clock HHMM
yrday_locallocal day and decimal time, as 326.5 for the 326th day of the year, or November 22 at 1200 hours (noon) unitless
lat_startlatitude at starting time of measurement (west is negative), in decimal degrees decimal degrees
lon_startlongitude at starting time of measurement; in decimal degrees (negative denotes West) decimal degrees
distance_startdistance from start of the transect? nautical miles
depth_startdepth at the start of the haul meters
temp_startwater temperature at measurement depth degrees Celsius
time_end_localending time of haul, local time , 24 hour clock HHMM
lat_endlatitude at end time of measurement; in decimal degrees (negative denotes South) decimal degrees
lon_endlongitude at end time of measurement; in decimal degrees (negative denotes West) decimal degrees
depth_enddepth at the end of the haul meters
temp_endwater temperature at measurement depth degrees Celsius
habitatnearshore, shelf, slope, or offshore unitless
name_commoncommon name: chum, pink or sockeye unitless
speciesgenus and species name of the fish Genus and Species
comments_dietcomments pertaining to the salmon stomach contents unitless
comments_haulcomments pertaining to the haul unitless
distance_enddistance along the transect at the end of the haul? unitless
weight_wetwet weight grams
sexM = male; F = female M or F
pred_stom_wgtpredator stomach weight grams
pred_fullObjective measure of how full the stomach was. (1 = least full, 7 = most full) unitless
prey_wgtprey weight grams
prey_digObjective measure of how digested prey in diet is (1 = most fresh; 5 = most digested) unitless
prey_countnumber of prey found in stomach contents count
prey_id_nodcprey identification, NODC standard name unitless
prey_nodc_common_nameprey common name, using NODC standards unitless
cruiseidcruise identifier unitless


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Instruments

Dataset-specific Instrument Name
Midwater Trawl
Generic Instrument Name
Midwater Trawl
Dataset-specific Description
Fish samples were collected using a midwater rope trawl, which is 198-m long, has hexagonal mesh in wings and body, and has a 1.2-cm mesh liner in the codend. The rope trawl was towed at 3.5 to 5 kt, at or near surface, and had a typical spread of 40-m horizontally and 14-m vertically. All tows lasted 30 minutes and covered 1.5 to 2.8 nautical miles. All fish sampling was done during daylight hours.
Generic Instrument Description
A mid-water or pelagic trawl is a net towed at a chosen depth in the water column to catch schooling fish such as herring and mackerel. Midwater trawl nets have very large front openings to herd schooling fish toward the back end where they become trapped in the narrow "broiler". The sides of the deployed net are spread horizontally with two large metal foils, called "doors," positioned in front of the net. As the trawler moves forward, the doors, and therefore the net, are forced outward, keeping the net open. This instrument designation is used when specific make and model are not known.


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Deployments

GP0108

Website
Platform
F/V Great Pacific
Report
Start Date
2001-07-17
End Date
2001-08-06
Description
The July - August 2001 OCC/GLOBEC cruise focused on salmon (Oncorhynchus spp.), and zooplankton distribution, and physical properties (current, temperature, and salinity) along 11 transects beginning at Icy Point near northern Southeast Alaska and ending at Cape Kaguyak at the western end of Kodiak Island. Sampling along each transect occurred over the continental shelf of the Gulf of Alaska and beyond the 200-m slope and into oceanic depths. The purpose was to investigate the relationships between biological and physical oceanographic processes that affect the distribution of juvenile salmon in the coastal Gulf of Alaska. This deployment was also known as GP0101.

GP0207-01

Website
Platform
F/V Great Pacific
Report
Start Date
2002-07-11
End Date
2002-07-27
Description
NEP GLOBEC gave this cruise the designation GP0207 and NOAA gave this cruise the designation GP0201. The data say 0201. The cruise report, inventory and eventlog say GP0207. 18 May 2011, dld - This cruise consisted of Leg 1 and Leg 2. Metadata is edited to reflect this information gleaned from the event log and the cruise report. The cruise report starts with a transit, not the science. Leg 1 includes the 11-16 July 2002 transit from Dutch Harbor to Yakutat where science personnel and gear were picked up. The Leg ends on 27 July in Seward. Chief Scientist was Edward D. Cokelet. Leg 2 departed Seward on 28 July and arrived in Dutch Harbor on 8 August with Christine Kondzela as Chief Scientist.

MF0310

Website
Platform
R/V Miller Freeman
Report
Start Date
2003-07-18
End Date
2003-08-09


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Project Information

U.S. GLOBEC Northeast Pacific (NEP)


Coverage: Northeast Pacific Ocean, Gulf of Alaska


Program in a Nutshell

Goal: To understand the effects of climate variability and climate change on the distribution, abundance and production of marine animals (including commercially important living marine resources) in the eastern North Pacific. To embody this understanding in diagnostic and prognostic ecosystem models, capable of capturing the ecosystem response to major climatic fluctuations.

Approach: To study the effects of past and present climate variability on the population ecology and population dynamics of marine biota and living marine resources, and to use this information as a proxy for how the ecosystems of the eastern North Pacific may respond to future global climate change. The strong temporal variability in the physical and biological signals of the NEP will be used to examine the biophysical mechanisms through which zooplankton and salmon populations respond to physical forcing and biological interactions in the coastal regions of the two gyres. Annual and interannual variability will be studied directly through long-term observations and detailed process studies; variability at longer time scales will be examined through retrospective analysis of directly measured and proxy data. Coupled biophysical models of the ecosystems of these regions will be developed and tested using the process studies and data collected from the long-term observation programs, then further tested and improved by hindcasting selected retrospective data series.



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Program Information

U.S. GLOBal ocean ECosystems dynamics (U.S. GLOBEC)


Coverage: Global


U.S. GLOBEC (GLOBal ocean ECosystems dynamics) is a research program organized by oceanographers and fisheries scientists to address the question of how global climate change may affect the abundance and production of animals in the sea.

The U.S. GLOBEC Program currently had major research efforts underway in the Georges Bank / Northwest Atlantic Region, and the Northeast Pacific (with components in the California Current and in the Coastal Gulf of Alaska). U.S. GLOBEC was a major contributor to International GLOBEC efforts in the Southern Ocean and Western Antarctic Peninsula (WAP).



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Funding

Funding SourceAward
NSF Division of Ocean Sciences (NSF OCE)
National Oceanic and Atmospheric Administration (NOAA)

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