Northern Cook Inlet Chinook Salmon Marine Harvest Stock Composition Study Adam St. Saviour ADF&G Palmer Sport Fish Background photo courtesy of B. Jones ADF&G
Synopsis Background- mixed stock fisheries in NCI Objectives Study design- stratification, genetic reporting groups, sampling, analysis Preliminary results Acknowledgements and questions
Purpose To estimate the stock-specific harvests of Chinook salmon from the Tyonek subsistence fishery and the Northern District commercial set gillnet fishery to improve understanding of stock dynamics in Northern Cook Inlet (NCI) Photo courtesy http://www.adfg.alaska.gov/index.cfm?adfg=byareasubsistencecookinlet.fishinginfo
Background Mixed stock fisheries in NCI including large sport fisheries (eg. Deshka, Little Su) and several stocks of concern (eg. Alexander, Sheep, and Goose creeks) Photo courtesy www.circac.orgwp-contentuploadscook-inlet-satellite-image
Study Objectives 1) Estimate the proportion of Chinook salmon harvested by the Tyonek subsistence fishery and the UCI Northern District set gillnet commercial fishery by reporting group. 2)Estimate the age composition of these Chinook salmon. Secondary Objectives 1) Sample 70% of the commercial harvest for tissue, coded-wire tags (CWTs), age, sex, and length. Images http://www.landbigfish.com/images/fish/lbf_chinook_salmon.jpg; http://www.psmfc.org/chinookedr/images/oceanphase_chinook.jpg
Upper Cook Inlet; Northern District Stratified by time and area
Group (Reporting Group) West (NorthWestCI) Yentna (NorthWestCI) Susitna (NorthWestCI) Susitna (MatSu) Knik (MatSu) Knik (KnikTurnagain) Turnagain (KnikTurnagain) Kenai (KenaiKasilof) Kasilof (KenaiKasilof) SKenaiPen (SKenaiPen) Genetic Baseline and Reporting Groups UCI Northwest Susitna- Matanuska Knik-Turnagain Kenai Peninsula Fig 1. Barclay and Habicht 2015
Data Collection Sample size target of 70% of the Commercial Catch Maximum effort! Photos courtesy of N. Logelin ADF&G
Sampling Locations Processors Small buying stations
Boat launches Set net sites Tyonek Photos courtesy of C Jalbert and B. Jones ADF&G
Fish sampled for scales, Sex, Length, genetics, CWTs Photo courtesy of C Jalbert ADF&G
Scales are pressed in Acetate Read with a 10x microfiche Photos courtesy of C Jalbert ADF&G
Laboratory Analysis Samples sent to GCL with paired ASL and harvest date and area data DNA extracted from tissue samples and genotyped for 48 SNP markers specific to Cook Inlet Chinook
Mixed Stock Analysis (MSA) Uses a Bayesian algorithm to estimate the most probable contribution of the baseline populations to explain the combination of genotypes in the mixture sample.
Detailed quantitative methods Baseline L J l 1 1 J l P q g,k q g,k,l,j. l=1 j=1 Mixture P z m t,d π t,d = π g,k,t,d G C g g=1 k=1 t,d z m,g,k. E φ g,k,t,d Stock Proportions = D d =1 e τ g,k,t d d g,k,t 2 Φ ωg,k,t 2τ g,k,t d dg,k,t e τ g,k,t d d g,k,t 2 Φ ωg,k,t 2τ g,k,t d dg,k,t. Run Timing Parameters Absolute Abundance P dg,k,t d g,k, σ 2 T 1 2 σ e 2σ2 d g,k,t d g,k T 2. T 1 N = t T g G k K N g,k,t t T g G k K P g,kλ g,k,t. Slide courtesy of K. Shedd ADF&G
Timeline November 2015 Scales aged, ASL composition estimates completed June 2016 Complete third season of field collections July 2016 DNA extractions from 2014 2016 genotyped by GCL August 2016 MSA completed September 2016 Harvest estimates completed by temporal, geographic strata and reporting group October November 2016 Draft report
Preliminary Results 2014 Sampled 55% of directed Northern District Commercial harvest and 29% of Subsistence harvest. 2015 Sampled 91% of directed Northern District Commercial harvest and 46% of estimated Subsistence harvest. Photos courtesy of B. Jones ADF&G
Length (mm) Age and Sex Compositions 2014 48 % Female all ages 2015 40% Female all ages 50% 45% 40% 35% 30% 25% 20% 15% 10% 5% 0% % Age Comp 1.1 1.2 1.3 1.4 1.5 Age 2014 2015 1000 900 800 700 600 500 400 300 200 100 0 Length At Age 1.1 1.2 1.3 1.4 1.5 Age 2014 2015
Big Picture Comprehensive run estimate for Susitna and Yenta rivers Brood tables, Biological Escapement Goals, and Forecasts http://earthobservatory.nasa.gov/iotd/view.php?id=79321
Acknowledgements Former PI s Jack Erickson and Davin Holen; Area coordinators Chase Jalbert, Jay Baumer, Nick Logelin, Bronwyn Jones; Samplers Eric Scacht, Dustin Murray, Matt Sutherland, Madeline Fox, Johnna Elkins, Derek Williams, Donny Archer, Ben Cohen, Paul Kuriscak, Bruce Whelan, Hans Thompsen ADF&G Gene Conservation Lab Copper River, Favco, Pacific Star, Snug Harbor, Tanners, Peninsula seafood processors Alaska Sustainable Salmon Fund Questions