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Status of Stocks & Multispecies Assessment Program

Strong Showing of REFM Staff at the American Fisheries Society Annual Meeting

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The American Fisheries Society (AFS) annual meeting was held in Portland, Oregon, 16–20 August,  and the close proximity to Seattle allowed for several members of REFM staff to attend.  The warm and sunny weather and free transit passes encouraged attendants to explore this outdoor-friendly city and to attend the many organized social events.  In establishments all around town patrons could be heard discussing fisheries and the symposia they had attended.  This was a wonderful venue to meet future collaborators and reconnect with old friends.   

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Susanne McDermott, Sandi Neideitcher, and Paul Spencer from the Status of Stocks & Multispecies Assessment (SSMA) program helped organized a symposium on reproductive biology titled “Breaking out of the spawning biomass paradigm: Skipped spawning, multiple spawning, and other complexities in the assessment of reproductive potential.” This symposium was organized as part of the NMFS nationwide Maturity Assessment and Reproductive Variability of Life Stages (MARVLS) group.  The symposium examined how deviations from our traditional stock assessment assumptions about spawning frequency and variability in reproductive output matter to stock assessment definitions of reproductive potential usually represented by spawning biomass. It included talks on skipped spawning, multiple spawning, maternal effects and variability in atresia. Scientists presented findings on fish stocks with nontraditional spawning patterns or variability in reproductive output and their effects on spawning biomass estimation. 

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Figure 1. Partial residuals showing overall trend of higher fecundity levels in Shelikof and along the Aleutian Islands, the Eastern Bering Sea has lower fecundity levels (warm colors = higher levels of fecundity, cool colors = lower levels of fecundity) with weight, year, mean egg diameter held at median values. Other variables held at their median values. Figure by Benjamin Williams, University of Alaska, Fairbanks

Two additional symposia, “Reproductive biology and population models in fisheries: are we assuming too much?” and “Novel insights from skip spawning in exploited fishes” were scheduled in sequential time slots providing researchers 2 days of focus on reproductive biology.  Sandi Neidetcher gave an oral presentation “Walleye pollock reproductive development described through image analysis software: implications for stock assessment” where she provided the initial findings from a project which analyzed 20 years of walleye pollock ovary specimens to address variation in fecundity associated with environmental factors (Fig. 1).  Paul Spencer also presented a poster for this symposia titled “How effective are marine protected areas for managing stocks with maternal effects in larval survival?” 

Anne Hollowed gave the keynote address for the symposium: “Incorporating ecosystem dynamics in fishery stock assessment and management: progress and challenges.” Her presentation examined how climate change and other ecosystem dynamics are being addressed in management of Gulf of Alaska and Bering Sea fisheries.  Stephani Zador presented “The use of ecosystem indicators in management: North Pacific perspective” during the symposium “Ecosystem-based fishery management (EBFM): it’s not as daunting as some think,” which sought to bring together scientists, managers, and fishing stakeholders working at the forefront of EBFM.  Kirstin Holsman presented “Quantitative clairvoyance or deductive delusion? Do multi-species models improve fisheries management advice?” during a symposia highlighting successful efforts that incorporate ecosystem science into management action. Coauthors for this work included Anne Hollowed, James Ianelli, and Kerim Aydin.  Kirstin Holsman also submitted a poster for “Multispecies modeling (including humans!) for “Fisheries management: where are we now and where can we go?” titled “Evidence for trophic amplification and attenuation of climate change impacts on groundfish species productivity in the Bering Sea, Alaska.” Other contributors for this poster included Anne Hollowed, Kerim Aydin, James Ianelli, and Paul Spencer.

Carey McGilliard described a management strategy evaluation to evaluate a harvest control rule based on specifying an acceptable probability of overfishing and using multi-model inference to estimate what the probability of overfishing would be under a range of catch limits.  The title of her talk was “Evaluating alternative harvest strategies for Alaska groundfish fisheries based on estimates of the probability of overfishing.”  Ingrid Spies presented during the symposium “Space oddity: recent advances incorporating spatial processes in the fishery stock assessment and management interface.” The objective of this symposium is to facilitate discussion and collaborative interaction on contemporary spatial applications in fisheries, particularly those that can be directly incorporated into spatial population dynamics models or management strategies. The title of Ingrid’s talk was: “Bridging the gap between fisheries genetics and management.”.  And Olav discussed the limits of our knowledge regarding forage fish stocks in Alaska and described some progress we have made in combining different sources of information during his presentation: “The fathomless frustrations of finding forage fishes: Difficulties in the assessment of Alaska stock.”

Many staff members participated in Gutshop 2015: “New Perspectives on Feeding Ecology of Fishes” aimed to present new perspectives on the feeding ecology and trophic dynamics of freshwater and marine fishes.  Kerim Aydin presented “From bites to bytes: the use of fish food habits data in ecosystem modeling” and Ivonne Ortiz and Kerim Aydin provided “Should I stay or should I go now? Simulating fish feeding ecology in the Bering Sea.”  Richard Hibpshman and coauthors Kimberly Sawyer, Sean Rohan, Caroline Robinson, Kerim Aydin, Troy Buckley, Mei-Sun Yang and Geoff Lang presented a poster titled “Resource Ecology and Ecosystem Modeling trophic interactions laboratory.”

Mike Levine (SMMA) and Susanne McDermott presented a poster titled “Taking advantage of pre-existing platforms: opportunistic use of a towed stereo video system during Atka mackerel tagging research”.  This research featured a custom built go pro stereo camera system.  The video transects were analyzed for benthic habitat characteristics as well as fish species composition and size frequency distribution.  The towed camera system has the potential to be applied in more rigorous surveys of Atka mackerel habitat and abundance.  Susanne McDermott also presented a poster titled ‘Effects of maternal growth on fecundity and egg quality of wild and captive Atka mackerel (Pleurogrammus monopteyrius)” where she showed that regional growth differences in Atka mackerel have effects on relative fecundity with larger and heavier fish showing higher relative fecundity (eggs per gram of bodyweight) than smaller fish.

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Figure 2. Ingrid Spies presented research on incorporating genetics into fisheries management. Results showed that establishing management units based on the results of genetic testing resulted in less depletion of sub-populations

Staff from the Age and Growth program participated by presenting posters during the “Use of scales, otoliths and fin rays to determine age, growth, and life history characteristics of fishes” symposia. Bomb dating and age estimates of big skate (Beringraja binoculata) and longnose skate (Raja rhina).”  Participating REFM authors included Thomas Helser, Christopher Gburski, Craig Kastelle, and Mary Elizabeth Matta. Christopher Gburski also contributed to “What to do when dogfish lie about their age?”  for Frontiers in otolith chemistry: insights, advances and future directions. And, Craig Kastelle presented “Age validation of Pacific cod (Gadus macorcephalus) using high resolution stable oxygen isotope (d18O) signatures in otoliths.” His coauthors from REFM included Thomas Helser, Delsa  Anderl, Mary Elizabeth Matta.

Posters submitted to the communities and ecosystems session included “Alaska Fisheries Science Center food habits database” by Geoff Lang, Mei-Sun Yang, Richard Hibpshman, Caroline Robinson, Sean Rohan, and Kimberly Sawyer and “Should I stay or should I go now? Simulating fish feeding ecology in the Bering Sea” by Ivonne Ortiz, Kerim Aydin and others (Fig. 2) . Ivonne Ortiz and Elizabeth Logerwell contributed to a poster titled “Marine Aleutian Islands synthesis” Additional posters included “Utilizing Fishset to model the economic impacts of fisheries management actions and environmental change” presented by Alan Haynie, and “Harvest strategies for multispecies fisheries under catch constraints” contributed by Carey McGilliard, James Ianelli, Grant Thompson, and Anne Hollowed. 

By Sandi Neidetcher

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