Preview of the 2013 Eastern Bering Sea Pollock Stock Assessment

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Preview of the 2013 Eastern Bering Sea Pollock Stock Assessment

When: November 6, 2013; 4:00 to 5:30 p.m.; Reception 5:30 to 6:30 p.m.
Where: Fishery Sciences Building, University of Washington, 1122 N.E. Boat Street, Seattle,
Room 102 (Auditorium)

Washington Sea Grant, the School of Aquatic and Fishery Sciences, and the University of Washington College of the Environment invite you to attend a preview of the most recent assessment of the Eastern Bering Sea (EBS) pollock — the target of one of the world’s largest fisheries — on November 6 at 4:00
p.m. The purpose of this forum is to provide fishery stakeholders and the public the opportunity to learn about the status of the EBS pollock stock and to ask questions and discuss the science underlying the assessment. Dr. James Ianelli, NMFS Alaska Fishery Science Center scientist, will present the EBS pollock assessment model and the most recent assessment of trends in the EBS pollock stock, including the recommended ABC (Allowable Biological Catch) for the fishery in 2014. Survey scientists for both the bottom trawl and acoustic-trawl surveys will be on hand to participate in the discussion. A reception will follow. We regret that the meeting room lacks teleconferencing capability.

Parking is available in a pay lot on the west side of the building, and limited metered parking is available on Boat Street.

Map: http://www.washington.edu/maps/?l=FSH

Directions: http://www.fish.washington.edu/info/find_us.html#directions

For more information: Ed Melvin, Washington Sea Grant, edmelvin@uw.edu or 206 543 9968.

Downloadable PDF of this event: Pollock_Workshop2013

Size selectivity of predation by brown bears depends on the density of their sockeye salmon prey.

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Related Articles

Size selectivity of predation by brown bears depends on the density of their sockeye salmon prey.

Am Nat. 2013 May;181(5):663-73

Authors: Cunningham CJ, Ruggerone GT, Quinn TP

Abstract
Can variation in prey density drive changes in the intensity or direction of selective predation in natural systems? Despite ample evidence of density-dependent selection, the influence of prey density on predatory selection patterns has seldom been investigated empirically. We used 20 years of field data on brown bears (Ursus arctos) foraging on sockeye salmon (Oncorhynchus nerka) in Alaska, to test the hypothesis that salmon density affects the strength of size-selective predation. Measurements from 41,240 individual salmon were used to calculate variance-standardized selection differentials describing the direction and magnitude of selection. Across the time series, the intensity of predatory selection was inversely correlated with salmon density; greater selection for smaller salmon occurred at low salmon densities as bears’ tendency to kill larger-than-average salmon was magnified. This novel connection between density dependence and selective predation runs contrary to some aspects of optimal foraging theory and differs from many observations of density-dependent selection because (1) the direction of selection remains constant while its magnitude changes as a function of density and (2) stronger selection is observed at low abundance. These findings indicate that sockeye salmon may be subject to fishery-induced size selection from both direct mechanisms and latent effects of altered predatory selection patterns on the spawning grounds, resulting from reduced salmon abundance.

PMID: 23594549 [PubMed – indexed for MEDLINE]

via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/pubmed/23594549?dopt=Abstract

Methods for estimating spatial trends in Steller sea lion pup production using the Kalman filter.

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Methods for estimating spatial trends in Steller sea lion pup production using the Kalman filter.

Ecol Appl. 2013 Sep;23(6):1455-74

Authors: Fay G, Punt AE

Abstract
Many species exhibit spatially varying trends in population size and status, often driven by differences among factors affecting individual subpopulations. Estimation and differentiation of such trends may be important for management, and a driving force for monitoring programs. The ability to estimate spatial differences in population trend may depend on assumptions regarding connectivity among subpopulations (stock structure or spatial overlap in stressors), information that is often poorly known. Linear state-space models using the Kalman filter were developed, tested, and applied for trend estimation of pup production for the western Alaska stock of Steller sea lions (Eumetopias jubatus), given only count data. Models were able to estimate trends and abundance even when data were missing. Models that assumed spatial correlation in trend among rookeries were more robust to stock structure assumptions when the stock structure was potentially mis-specified. High levels of spatial correlation among rookeries estimated from Steller sea lion pup count data are consistent with large-scale covariance of population trend within the Steller sea lion metapopulation.

PMID: 24147416 [PubMed – in process]

via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/pubmed/24147416?dopt=Abstract

Secondary contact and changes in coastal habitat availability influence the nonequilibrium population structure of a salmonid (Oncorhynchus keta).

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Secondary contact and changes in coastal habitat availability influence the nonequilibrium population structure of a salmonid (Oncorhynchus keta).

Mol Ecol. 2013 Oct 1;

Authors: Petrou EL, Hauser L, Waples RS, Seeb JE, Templin WD, Gomez-Uchida D, Seeb LW

Abstract
Numerous empirical studies have reported lack of migration-drift equilibrium in wild populations. Determining the causes of nonequilibrium population structure is challenging because different evolutionary processes acting at a variety of spatiotemporal scales can produce similar patterns. Studies of contemporary populations in Northern latitudes suggest that nonequilibrium population structure is likely caused by recent colonization of the region after the last Pleistocene ice age ended ~13,000 years ago. The chum salmon’s (Oncorhynchus keta) range was fragmented by dramatic environmental changes during the Pleistocene. We investigated the population structure of chum salmon on the North Alaska Peninsula (NAP) and, using both empirical data and simulations, evaluated the effects of colonization timing and founder population heterogeneity on patterns of genetic differentiation. We screened 161 single nucleotide polymorphisms and found evidence of nonequilibrium population structure when the slope of the isolation by distance relationship was examined at incremental spatial scales. In addition, simulations suggested that this pattern closely matched models of recent colonization of the NAP by secondary contact. Our results agree with geological and archaeological data indicating that the NAP was a dynamic landscape that may have been more recently colonized than during the last deglaciation because of dramatic changes in coastal hydrology over the last several thousand years. This article is protected by copyright. All rights reserved.

PMID: 24118255 [PubMed – as supplied by publisher]

via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/pubmed/24118255?dopt=Abstract

ONLINE DEBATE: Large no-take areas – Is their total environmental impact positive or negative? With Callum Roberts and Ray Hilborn

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ONLINE DEBATE: Large no-take areas – Is their total environmental impact positive or negative? With Callum Roberts and Ray Hilborn

Date: Tuesday, Oct 8, 2013
Time: noon US EDT / 9 am US PDT / 4 pm GMT
To join the debate on Oct 8: http://openchannels.org/node/4410

This will be an online, text-based debate on whether the total environmental impact of large no-take areas is ultimately positive or negative. The audience will be able to comment and ask questions throughout the debate. The event is co-hosted by OpenChannels, MPA News, and the EBM Tools Network.

*  Callum Roberts will argue that the total environmental impact of large no-take areas – such as Australia’s recently designated 500,000-km2 no-take area in the Coral Sea – is positive. Callum is a professor of marine conservation biology at York University (UK) where he studies the use of no-take areas as tools for biodiversity conservation and fishery management, among other subjects. He authored the books “The Unnatural History of the Sea” and “The Ocean of Life: Fate of Man and the Sea”, and has served on advisory panels to multiple ocean studies commissions.

*  Ray Hilborn will argue that the total environmental impact of large no-take areas may be negative due to the need to make up food production from other, more environmentally damaging methods, either at sea or on land. Ray is a professor in the School of Aquatic and Fishery Sciences at the University of Washington where he studies conservation, natural resource management, and fisheries stock assessment and risk analysis. He has published over 200 peer-reviewed articles and is author of “Overfishing: What Everyone Needs to Know”, published by Oxford University Press.

About the debate format:

This event will take place on www.OpenChannels.org, the knowledge-sharing forum for ocean planners and managers worldwide. It will be a live interactive debate conducted by typing and reading text – there is no audio component.

Audience members will be able to post comments in response to Callum and Ray’s arguments as the debate is occurring, and Callum and Ray may address those comments as they wish.

You do not need to be logged into OpenChannels.org to participate in the debate, but you are encouraged to create a user account and log in so you do not need to type your name in every post.

To join the debate on Oct 8: http://openchannels.org/node/4410

Brain Acetylcholinesterase Activity in Shiner Perch (Cymatogaster aggregata) and Juvenile Chinook Salmon (Oncorhynchus tshawytscha) After Application of Carbaryl to Control Burrowing Shrimp Within Willapa Bay, Washington.

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Brain Acetylcholinesterase Activity in Shiner Perch (Cymatogaster aggregata) and Juvenile Chinook Salmon (Oncorhynchus tshawytscha) After Application of Carbaryl to Control Burrowing Shrimp Within Willapa Bay, Washington.

Arch Environ Contam Toxicol. 2013 Sep 17;

Authors: Troiano AT, King KA, Grue CE, Grassley JM, Ekblad CJ

Abstract
Carbaryl has been applied in Willapa Bay, Washington, for five decades to control burrowing shrimp (Neotrypaea californiensis and Upogebia pugettensis) on commercial oyster (Crassostrea gigas) beds. Concerns about effects on nontarget species, including fishes, have led to restrictions in use despite a lack of data on in situ exposure. We measured brain acetylcholinesterase (AChE) activity in adult Shiner perch (Cymatogaster aggregata) and juvenile Chinook salmon (Oncorhynchus tshawytscha) after operational applications. We hypothesized that exposure in Shiner perch would be greater than in juvenile Chinook salmon because of their greater site fidelity and benthic foraging. However, Shiner perch exhibited no statistically significant AChE inhibition. Enzyme activity was statistically decreased (≤14 %) in juvenile Chinook salmon after a second spray event; however, inhibition was less than that associated with overt effects and was similar to controls by 48 h after the spray. Diet analyses confirmed that Shiner perch were primarily feeding on benthic invertebrates and that juvenile Chinook salmon were feeding primarily within the water column. Composition of Shiner perch diets and amount of food consumed varied little among channels and time periods; however, Shiner perch on beds consumed more food 6 h after application than those at other time points and locations. There were no consistent differences in the diets of juvenile Chinook salmon within channels among time periods. Results suggest (1) that carbaryl applications pose little hazard to fish in the bay having habitat and dietary preferences similar to those of Shiner perch and juvenile Chinook salmon and (2) that quantification of direct exposure in the field is essential to adequately assess risk.

PMID: 24042340 [PubMed – as supplied by publisher]

via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/pubmed/24042340?dopt=Abstract

Relationship between effective population size, inbreeding and adult fitness-related traits in a steelhead (Oncorhynchus mykiss) population released in the wild.

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Relationship between effective population size, inbreeding and adult fitness-related traits in a steelhead (Oncorhynchus mykiss) population released in the wild.

Mol Ecol. 2013 Mar;22(5):1295-309

Authors: Naish KA, Seamons TR, Dauer MB, Hauser L, Quinn TP

Abstract
Inbreeding is of concern in supportive breeding programmes in Pacific salmonids, Oncorhynchus spp, where the number of breeding adults is limited by rearing space or poor survival to adulthood, and large numbers are released to supplement wild stocks and fisheries. We reconstructed the pedigree of 6602 migratory hatchery steelhead (Oncorhynchus mykiss) over four generations, to determine the incidence and fitness consequences of inbreeding in a northwest USA programme. The hatchery maintained an effective population size, Ñ(e) = 107.9 from F(0) to F(2), despite an increasing census size (N), which resulted in a decreasing N(e)/N ratio (0.35 in F(0) to 0.08 in F(2)). The reduced ratio was attributed to a small broodstock size, nonrandom transfers and high variance in reproductive success (particularly in males). We observed accumulation of inbreeding from the founder generation (in F(4), percentage individuals with inbreeding coefficients Δf > 0 = 15.7%). Generalized linear mixed models showed that body length and weight decreased significantly with increasing Δf, and inbred fish returned later to spawn in a model that included father identity. However, there was no significant correlation between Δf and age at return, female fecundity or gonad weight. Similarly, there was no relationship between Δf and reproductive success of F(2) and F(3) individuals, which might be explained by the fact that reproductive success is partially controlled by hatchery mating protocols. This study is one of the first to show that small changes in inbreeding coefficient can affect some fitness-related traits in a monitored population propagated and released to the wild.

PMID: 23379933 [PubMed – indexed for MEDLINE]

via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/pubmed/23379933?dopt=Abstract

Citation patterns of a controversial and high-impact paper: Worm et al. (2006) “Impacts of biodiversity loss on ocean ecosystem services”.

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Citation patterns of a controversial and high-impact paper: Worm et al. (2006) “Impacts of biodiversity loss on ocean ecosystem services”.

PLoS One. 2013;8(2):e56723

Authors: Branch TA

Abstract
Citation patterns were examined for Worm et al. 2006 (Science 314:787-790), a high-impact paper that focused on relationships between marine biodiversity and ecosystem services. This paper sparked much controversy through its projection, highlighted in the press release, that all marine fisheries would be collapsed by 2048. Analysis of 664 citing papers revealed that only a small percentage (11%) referred to the 2048 projection, while 39% referred to fisheries collapse in general, and 40% to biodiversity and ecosystem services. The 2048 projection was mentioned more often in papers published soon after the original paper, in low-impact journals, and in journals outside of fields that would be expected to focus on biodiversity. Citing papers also mentioned the 2048 projection more often if they had few authors (28% of single-author papers vs. 2% of papers with 10 or more authors). These factors suggest that the more knowledgeable the authors of citing papers were about the controversy over the 2048 projection, the less likely they were to refer to it. A noteworthy finding was that if the original authors were also involved in the citing papers, they rarely (1 of 55 papers, 2%) mentioned the 2048 projection. Thus the original authors have emphasized the broader concerns about biodiversity loss, rather than the 2048 projection, as the key result of their study.

PMID: 23437224 [PubMed – indexed for MEDLINE]

via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/pubmed/23437224?dopt=Abstract

High-throughput sequencing and pathway analysis reveal alteration of the pituitary transcriptome by 17α-ethynylestradiol (EE2) in female coho salmon, Oncorhynchus kisutch.

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High-throughput sequencing and pathway analysis reveal alteration of the pituitary transcriptome by 17α-ethynylestradiol (EE2) in female coho salmon, Oncorhynchus kisutch.

Aquat Toxicol. 2013 Aug 9;142-143C:146-163

Authors: Harding LB, Schultz IR, Goetz GW, Luckenbach JA, Young G, Goetz FW, Swanson P

Abstract
Considerable research has been done on the effects of endocrine disrupting chemicals (EDCs) on reproduction and gene expression in the brain, liver and gonads of teleost fish, but information on impacts to the pituitary gland are still limited despite its central role in regulating reproduction. The aim of this study was to further our understanding of the potential effects of natural and synthetic estrogens on the brain-pituitary-gonad axis in fish by determining the effects of 17α-ethynylestradiol (EE2) on the pituitary transcriptome. We exposed sub-adult coho salmon (Oncorhynchus kisutch) to 0 or 12ng EE2/L for up to 6 weeks and effects on the pituitary transcriptome of females were assessed using high-throughput Illumina(®) sequencing, RNA-Seq and pathway analysis. After 1 or 6 weeks, 218 and 670 contiguous sequences (contigs) respectively, were differentially expressed in pituitaries of EE2-exposed fish relative to control. Two of the most highly up- and down-regulated contigs were luteinizing hormone β subunit (241-fold and 395-fold at 1 and 6 weeks, respectively) and follicle-stimulating hormone β subunit (-3.4-fold at 6 weeks). Additional contigs related to gonadotropin synthesis and release were differentially expressed in EE2-exposed fish relative to controls. These included contigs involved in gonadotropin releasing hormone (GNRH) and transforming growth factor-β signaling. There was an over-representation of significantly affected contigs in 33 and 18 canonical pathways at 1 and 6 weeks, respectively, including circadian rhythm signaling, calcium signaling, peroxisome proliferator-activated receptor (PPAR) signaling, PPARα/retinoid x receptor α activation, and netrin signaling. Network analysis identified potential interactions between genes involved in circadian rhythm and GNRH signaling, suggesting possible effects of EE2 on timing of reproductive events.

PMID: 24007788 [PubMed – as supplied by publisher]

via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/pubmed/24007788?dopt=Abstract

How stock of origin affects performance of individuals across a meta-ecosystem: an example from sockeye salmon.

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How stock of origin affects performance of individuals across a meta-ecosystem: an example from sockeye salmon.

PLoS One. 2013;8(3):e58584

Authors: Griffiths JR, Schindler DE, Seeb LW

Abstract
Connectivity among diverse habitats can buffer populations from adverse environmental conditions, influence the functioning of meta-ecosystems, and ultimately affect the reliability of ecosystem services. This stabilizing effect on populations is proposed to derive from complementarity in growth and survival conditions experienced by individuals in the different habitats that comprise meta-ecosystems. Here we use the fine scale differentiation of salmon populations between diverse lake habitats to assess how rearing habitat and stock of origin affect the body condition of juvenile sockeye salmon. We use genetic markers (single nucleotide polymorphisms) to assign individuals of unknown origin to stock group and in turn characterize ecologically relevant attributes across habitats and stocks. Our analyses show that the body condition of juvenile salmon is related to the productivity of alternative habitats across the watershed, irrespective of their stock of origin. Emigrants and residents with genetic origins in the high productivity lake were also differentiated by their body condition, poor and high respectively. These emigrants represented a substantial proportion of juvenile sockeye salmon rearing in the lower productivity lake habitat. Despite emigrants originating from the more productive lake, they did not differ in body condition from the individuals spawned in the lower productivity, recipient habitat. Genetic tools allowed us to assess the performance of different stocks groups across the diverse habitats comprising their meta-ecosystem. The ability to characterize the ecological consequences of meta-ecosystem connectivity can help develop strategies to protect and restore ecosystems and the services they provide to humans.

PMID: 23505539