Greg Albrecht Dr. Sarah M. Hardy Dr. Kris Hundertmark

Species information Study area Factors influencing current populations Purpose of study Methods Progress

Distribution (Approximated) Koryaks.net

Life History Planktonic zoea – (hatch in winter – spring, 2 stages, 3-5 months) Settle as megalopae Molt through 7-9 instars Males: 5-10 years Females: 3-7 years Terminal molt to maturity Up to 7 years post terminal molt Males: years Females: years uwlax.edu Kruse et al. 2007

Shell condition Index (Not full representation) Abdominal flap is proportionally larger in mature females

Mating Mating in late winter Females can store sperm in spermathaeca for later use Males can fertilize several females Young are brooded months then released into water column FemaleMale

Larval Dispersal Predominantly northward flow Bering Strait to Pt. Barrow ~6 months Weingartner et al. 2005

Bering Sea Local recruitment Eddies Weak currents in central Southward migration? Stabeno 2001 Mean circulation of upper 40 m

Migration Adult females move from coastal domain towards outer domain (SW) Male migration not studied as well Koryaks.net Ernst et al. 2005

The forces at work Commercial fishing pressure Concentrating on southern extent of population Climate change Temperatures, ice extent, ocean currents, wind & mixing Predator prey Pacific Cod (Gadus macrocephalus) and other bottom fish Resource exploration

Commercial Harvest One of the largest crab fisheries in the world 2008~ 90 million dollars 1992~ 192 million Replaced dwindling Tanner (C. bairdi) stocks in 1980s rcrawford79.wordpress.com Kruse et al. 2007

Climate change Ice extent determines cold pool (<2  C) Cold pool trapped by stratified warm water Crabs follow cold pool Can crabs re-colonize south after a warm year? Cod predation may be too intense Orensanz et al. 2004

Resource Exploration Areas Alaska Annual Studies Plan. U.S. Dept. of Interior 2009

Purpose of Study Gain a better understanding of genetic connectivity Identify genetically distinct subpopulations if they exist Gain a better understanding of larval dispersal distances

Sampling Sampled Commercial fishing Planned sampling Resource development

Methods Based on Puebla et al (North Atlantic) Extract DNA samples from tissue in ~ 1000 adult female C. opilio samples collected from throughout their range Amplify DNA using PCR at 8 microsatellite locations Genotype each individual Use statistical programs to analyze results and look for distinct populations Match larval crabs with upstream populations

Why Microsatellites? Definition: Molecular markers consisting of repeat nucleotide units at various locations within nuclear DNA Previously established for this species by Puebla et al Shown to be informative in this species Highly polymorphic, yet not under selection pressures Deviation from Hardy-Weinberg equilibrium can be used to detect isolation of a group of individuals

Statistics A suite of computer programs will be used to identify genetically isolated populations F-statistics Compare pre-established groups in a framework similar to ANOVA Bayesian methods Assemble populations based on similarity of genetic signatures

The big picture 8 primers (Identify region for copying) Taq polymerase (Copies DNA) Crab DNA PCR (Copying of target DNA) Electrophoresis Scoring of each individual’s electropherogram Statistical analysis of genetic signatures

Microsatellite locations are represented by different colors

So how does this work?

PCR Allele “A”Allele “B” Heterozygote Primer region Population “A” Population “B” Electropherogram Mating Electrophoresis

100 PCR Allele “A” Homozygote Primer region Population “A” Electropherogram PCR conditions must be optimized for good amplification Mating Electrophoresis

Chukchi

Beaufort

Progress to date Extracted ~150 samples Tested DNA quality and found donated Bering samples to be low Multiplexed all 8 primers Trial and error of PCR conditions (various annealing temperatures and times, Taq polymerases) Initial genotyping of individuals

Timeline Winter 2009/10 – begin genotyping (currently underway) May 2010 – have completed genotyping and preliminary statistical analysis for 60 individuals July 2010 – Collect samples from Bering Sea on F&G trawl survey cruise February 2011 – have completed genotyping and analysis for entire sample collection September 2011 – have written and defended thesis

Literature Cited Ernst, B., Orensanz J. M. & Armstrong, D. A Spatial dynamics of female snow crab (Chionoecetes opilio) in the eastern Bering Sea. Canadian Journal of Fisheries and Aquatic Science 62: Kruse, G.H., Tyler, A.V, Sainte-Marie, B., Pengilly, D A workshop on mechanisms affecting year-class strength formation in snow crabs Chionoecetes opilio in the Eastern Bering Sea Orensanz, J., B. Ernst, D. A. Armstrong, P. Stabeno, and P. Livingston Contraction of the geographic range of distribution of snow crab (Chionoecetes opilio) in the Eastern Bering Sea: An environmental ratchet? Pages 65-79, CalCOFI Report. Puebla, O., Parent, E. & Sevigny, J.-M New microsatellite markers for the snow crab Chionoecetes opilio (Brachyura: Majidae). Molecular Ecology Notes. 3: Puebla, O., Sevigny, J.-M., Sainte-Marie, B., Brethes, J.-C., Burmeister, A., Dawe, E. G. and Moriyasu. M Population genetic structure of the snow crab (Chionoecetes opilio) at the Northwest Atlantic scale. Canadian Journal of Fisheries and Aquatic Sciences 65: Stabeno, P.J., Kachel, N.B., Salo, S.A. & Schumacher, J.D On the temporal variability of the physical environment over the south-eastern Bering Sea. Fisheries Oceanography 10(1) Weingartner, T., Aagaard, K., Woodgate, R., Danielson, S., Yasunori, S. & Cavalieri, D Circulation on the north central Chukchi Sea shelf. Deep-Sea Research II 52:

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