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From: Brett Alger - NOAA Federal <[log in to unmask]> Date: Tuesday, April 7, 2020 at 11:12 AM To: Jim Schneider <[log in to unmask]>, Gretchen Hansen <[log in to unmask]>, "Myers, Jared" <[log in to unmask]>, Brian Langseth <[log in to unmask]>, Amy Schueller - NOAA Federal <[log in to unmask]> Subject: Fwd: Post-Doc at Northeast Fisheries Science Center Share widely :) ---------- Forwarded message --------- From: Andrew Jones - NOAA Federal <[log in to unmask]<mailto:[log in to unmask]>> Date: Tue, Apr 7, 2020 at 10:15 AM Subject: Post-Doc at Northeast Fisheries Science Center To: Andrew Jones - NOAA Federal <[log in to unmask]<mailto:[log in to unmask]>> please share with potential candidates: Post-Doctoral Research Opportunity: Spatio-Temporal Analyses of New England Fish Species with VAST PIs: Liz Brooks, Chris Legault, Charles Adams, Deborah Hart, Charles Perretti (Population Dynamics Branch at the Northeast Fisheries Science Center) Salary: $60,000/year Duration: 2 year research opportunity, second year funds contingent on federal budget and satisfactory progress Contact: For additional information, send email to: [log in to unmask]<mailto:[log in to unmask]> Summary: An opportunity to research the utility of VAST for combining multiple fishery-independent surveys and spatial covariates for use in stock assessment models through simulation and case studies. Particular emphasis on surveys and stocks in the Northeast U.S. region. Research Problem: Fishery-independent indices play an important role in stock assessment, and inform the model of relative trends in the fish population. There are a variety of fishery independent surveys conducted in the Northeast region of the US: spring and fall bottom trawl surveys conducted by the Northeast Fisheries Science Center (NEFSC) with a spatial footprint from the mouth of the Bay of Fundy, New Brunswick (CAN) to Cape Hatteras, NC; a spring bottom trawl survey conducted by DFO on Georges Bank; invertebrate surveys that sample areas in the Mid-Atlantic Bight, Georges Bank, and the Gulf of Maine; and the NEAMAP and other state surveys which sample primarily inshore waters. For any given stock assessment, multiple fishery-independent indices may be incorporated, despite differences in spatial coverage and survey timing. Depending on the season and the stock, the small state surveys may provide information on recruitment and/or juvenile trends, while the larger scale NEFSC surveys inform on trends of mature biomass. The index trends have traditionally been design-based estimators from the stratified random sampling survey design (depth defines the strata), often scaled up to swept area and including experimentally derived catchability coefficients for some species. An alternative approach to deriving indices is model-based, which effectively ignores the survey stratification and attempts to standardize the annual trend by accounting for factors that explain significant amounts of variance, given assumptions about the statistical distribution of the data. Recent work has led to development of spatial modeling tools to estimate abundance (or biomass), with the ability to account for spatial and/or temporal autocorrelation, and to distinguish between habitat and catchability covariates (program <https://urldefense.com/v3/__https:/github.com/James-Thorson-NOAA/VAST/wiki__;!!HXCxUKc!gV6yQU6LAjCFWEsPf4Fp3ESF_lfX2ER5KY_I3eD7SACsNwUOllZChjGMH9uPAlKeJQ$> VAST<https://urldefense.com/v3/__https:/github.com/James-Thorson-NOAA/VAST/wiki__;!!HXCxUKc!gV6yQU6LAjCFWEsPf4Fp3ESF_lfX2ER5KY_I3eD7SACsNwUOllZChjGMH9uPAlKeJQ$>). This modeling tool has seen increased application in recent years at several science centers, and we aim to explore applications to survey data for fish stocks managed by the NEFSC, including simulation studies to develop best practice guidelines for this region. Topics for consideration include: use the simulation capability of VAST to explore the impact of combining indices with different catchability, selectivity, timing, and degree of spatial (or temporal) overlap; provide guidance on how to standardize for those differences; and explore whether the inclusion of additional covariates collected on the surveys (e.g, bottom temperature, habitat information where available, abundance of other species, salinity) improves index standardization and interpretation of big-picture trends that may not be observable when focusing on one species at a time in a stock assessment meeting. -- Brett Alger Electronic Technologies Coordinator Office of Science & Technology NOAA Fisheries 1315 East West Highway Silver Spring MD 20910 O-(301) 427-8217 C-(978) 290-0186 [log in to unmask]<mailto:[log in to unmask]>