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Seafood distribution systems are often viewed as exogenous from fisheries and marine resource management. However, these systems are closely coupled. The transportation and transformation of fish out of water (i.e., distribution and processing) is affected by and affects the resource and those that exploit and manage it. Despite this linkage, the feedback between harvesting and post-harvesting activities has been largely unstudied, reinforcing an artificial disconnect. This paper brings focus to this gap by examining the interplay between seafood distribution and social-ecological resilience - arguably an important objective of fisheries management. Drawing on the notion of “portfolio” fishing, this paper seeks to extend the concept beyond the material boundaries of the resource itself and the individual strategies of those who harvest marine resources, using the Atlantic herring and Spiny dogfish in New England as case studies. The broader interpretation of portfolio fishing allows us to understand seafood distribution as a new axis of diversification that has direct implications for the social-ecological resilience of fisheries. Expanding the geography of resilience in fisheries inland, beyond the existing regulatory 'wrack line,' brings to focus the interrelatedness of fisheries and distribution, and raises challenging questions about how to deal with social-ecological systems that extend beyond the borders of regulatory control. [ABSTRACT FROM AUTHOR]

Ecosystem based modeling was used to determine the ecological role of spiny dogfish ( Squalus acanthias ), an opportunistic predator, in the northeast United States marine environment. Two time periods were modeled; one when spiny dogfish populations were depressed and one after recovery. According to our results, the ecological role of spiny dogfish has changed over time. During the depressed time period, spiny dogfish were not a keystone species and had little impact, positive or negative, on other species/groups in this ecosystem. Spiny dogfish currently have one of the highest trophic levels in this ecosystem and are akeystone species, having a high prey overlap with commercially depleted Atlantic cod ( Gadus morhua ). Spiny dogfish appear to have responded well to changes in this ecosystem caused by fishing and perhaps environmental change or a combination of both, while other species in the region have not. This is important, as spiny dogfish could now be potentially out competing commercially valuable and highly depleted populations of groundfish for resources. Based on our results, we suggest fisheries managers should look toward ecosystem based management measures in the future in order to actively and properly manage the ecosystem as a whole. [ABSTRACT FROM AUTHOR]

Multi-scaled integrated analysis across biological, economic, social, and political aspects of fisheries is needed to provide effective management strategies. These aspects are naturally conflicting and, when converged into objectives, are seldom optimized at the same time scale. For example, biological objectives are usually considered in the long-term, whereas socio-economic and political objectives are commonly considered in the short-term. Additionally, fishery managers have frequently struggled to integrate different information arising from each aspect of fishery management. The employment of integrative analysis to shark fishery management is particularly needed because of the unique biology and life history characteristics of sharks, and the increasing threat of human exploitation that affects their conservation status. One species that may serve as a model for the intersection of the myriad of aspects of elasmobranch management is the spiny dogfish ( Squalus acanthias). This commercial shark species was recently considered, unsuccessfully, for inclusion in trade-regulation lists due to international concern about its conservation status. The need to provide thorough integration of biology, life history, and ecology of spiny dogfish with information concerning the commercial trade, socio-economic, and political aspects of the fishery has now reached a critical juncture. We attempt to provide such an integration in this paper. First, we review basic biology and life history characteristics of spiny dogfish and then integrate this information into aspects of the international trade for the species. This is done using the framework of two of the most significant fishery management governance systems affecting the international management of the species and its conservation status (i.e., the Magnuson-Stevens Fishery Conservation and Management Act in the USA, and the Common Fisheries Policy in the European Union). Our analysis indicates that to achieve effective fishery management of spiny dogfish stocks and populations at international, national, regional, and local levels there is still the need to understand and integrate socio-economic, political and ecosystem-based aspects outside the framework of national fishery jurisdictions. [ABSTRACT FROM AUTHOR]

Increased commercial importance of spiny dogfish ( Squalus acanthias) combined with an often debated, and controversial, ecological impact has warranted an investigation of the relationship among distribution, environment, and prey to better understand the species ecology and inform management. To elucidate mechanisms behind distributional changes, we modeled seasonal occurrence and abundance of neonate, immature, and mature spiny dogfish as functions of abiotic and biotic factors using generalized additive models and Northeast Fisheries Science Center bottom trawl survey data. Significant nonlinear relationships were widespread throughout dogfish stages and seasons. Seasonal occurrence was tightly linked to depth and bottom temperature, with year and Julian day influential for some stages. While these factors also influenced abundance, ecological factors (e.g., squid abundances) significantly contributed to trends for many stages. Potential impacts of climate change were evaluated by forecasting distributions under different temperature scenarios, which revealed higher regional probabilities of occurrence for most stages during a warmer than average year. Our results can be used to better understand the relationship between sampling periods and movement drivers to survey catchability of the population in the Northeast (US) shelf large marine ecosystem. [ABSTRACT FROM AUTHOR]

Abstract: Elasmobranchs are the most commonly used experimental models among the jawed, cartilaginous fish (Chondrichthyes). Previously we developed cell lines from embryos of two elasmobranchs, Squalus acanthias the spiny dogfish shark (SAE line), and Leucoraja erinacea the little skate (LEE-1 line). From these lines cDNA libraries were derived and expressed sequence tags (ESTs) generated. From the SAE cell line 4303 unique transcripts were identified, with 1848 of these representing unknown sequences (showing no BLASTX identification). From the LEE-1 cell line, 3660 unique transcripts were identified, and unknown, unique sequences totaled 1333. Gene Ontology (GO) annotation showed that GO assignments for the two cell lines were in general similar. These results suggest that the procedures used to derive the cell lines led to isolation of cell types of the same general embryonic origin from both species. The LEE-1 transcripts included GO categories “envelope” and “oxidoreductase activity” but the SAE transcripts did not. GO analysis of SAE transcripts identified the category “anatomical structure formation” that was not present in LEE-1 cells. Increased organelle compartments may exist within LEE-1 cells compared to SAE cells, and the higher oxidoreductase activity in LEE-1 cells may indicate a role for these cells in responses associated with innate immunity or in steroidogenesis. These EST libraries from elasmobranch cell lines provide information for assembly of genomic sequences and are useful in revealing gene diversity, new genes and molecular markers, as well as in providing means for elucidation of full-length cDNAs and probes for gene array analyses. This is the first study of this type with members of the Chondrichthyes. [ABSTRACT FROM AUTHOR]

de la Torriente, A., Quiñones, R. A., Miranda-Urbina, D. A., and Echevarría, F. 2010. South American sea lion and spiny dogfish predation on artisanal catches of southern hake in fjords of Chilean Patagonia. – ICES Journal of Marine Science, 67: 294–303.The South American sea lion (Otaria flavescens) is a pinniped known to interact with fisheries, potentially damaging gear and lowering catches. Predation by O. flavescens and spiny dogfish (Squalus acanthias) on artisanal southern hake (Merluccius australis) catches in fjords of Chilean Patagonia is estimated and compared. Observations were made in the Gulf of Ancud and Comau Fjord in southern Chile from October 2005 to September 2006. Losses of southern hake catches to O. flavescens predation were 1.6% of the total catch of the species, and to spiny dogfish predation were slightly higher, at 3.3%. The predation of both species on southern hake catches varied throughout the year, but was lower in summer. Both predators showed a preference for adult southern hake over juveniles. There was no significant relationship between predation on southern hake catches by the sea lion and the availability of adult and juvenile southern hake on longlines (AHCL). However, there was a significant relationship (p < 0.05) between AHCL and spiny dogfish predation. Most O. flavescens interaction events (81.4%) were during longline retrieval. Our results showed minimal interactions between O. flavescens and the artisanal southern hake fishery in the area, so with the present abundance of O. flavescens, there is no justification for reducing the sea lion population by hunting. [ABSTRACT FROM PUBLISHER]

The article examines whether observer presence affects commercial fishers' fish bycatch reports in the ling (Genypterus blacodes) bottom longline (BLL) fishery in New Zealand through the implications of observer presence on reporting of particular bycatch species and on the weight of spiny dogfish reported. The data that were given reveals that misreporting of bycatch is common and can introduce significant errors into total catch estimation that can have serious implications for fishery sustainability.

Abstract: To estimate the short-term bycatch discard mortality of otter trawl captured spiny dogfish (Squalus acanthias), individuals caught by a Northwest Atlantic commercial bottom-trawl vessel using 45–60min tows were held in held in pens for 72-h trials in lieu of being released. Mortality rates were compared to those in minimally stressed hook-and-line (control) dogfish subjected to the same protocols. To interpret physiological consequences of trawl capture, blood acid–base parameters were also assessed in dogfish following capture by both trawling and the hook-and-line control. Whole-blood pH (significantly depressed), pCO2 (significantly elevated) and pO2 (significantly depressed) were all markedly disturbed in trawled dogfish, indicating that trawl capture elicited a far greater disruption to vascular acid–base balance. However, 72h mortality was not negligible for control dogfish (24%) but similar to trawling (29%), indicating that pens likely caused the observed (72h) mortality associated with both capture methods. Still, in evaluating the range of 72h trawling mortalities found across pen trials, estimated tow-weight was a significant predictor of mortality, explaining 67% of the variation. This suggests that penning stress was merely an additive factor compounding initial capture stress that dictated the 72h mortality of trawled individuals. When normalized by subtracting out hook-and-line pen mortality, 72h trawling mortality generally remained well below the 50.0% spiny dogfish discard mortality rate currently estimated for trawling in the Northwest Atlantic and was even superceded by penning stress in lighter tows; a testament to the resiliency of this species. However, catch-weights exceeding 200kg yielded rapid elevations in 72h mortality that more closely approached current estimates. This intimates that as tows become more heavily packed, potentially fatal damage inflicted on this species can heighten quickly. Spiny dogfish discard mortality is thus postulated as more commensurate with current estimations for otter trawling when tows are heavily packed. [Copyright &y& Elsevier]

1. Fish species are used globally for fundamental research, product and environmental testing, and education, but this use has not hitherto been documented. The number of fish used for research and education in North America currently represents approximately one-quarter of all animal use for these purposes; only mice are used in higher numbers. Data from the Canadian Council on Animal Care, various animal care committees from Canadian universities, and the United States Fish and Wildlife Service are collated and summarized. 2. In Canada nearly a half a million fish were used for research and education each year from 1996 to 2001. We estimated that the United States used over four times that amount for the same purposes, totalling approximately 2.8 million fish each year. 3. At least 100 fish species, representing 27 taxonomic orders, were used for research and education in North America from 1996 to 2001. Close to one-third of the species had life-history characteristics that might make them particularly susceptible to over-exploitation. This potential vulnerability, coupled with data from animal care facilities in Canada suggesting that nearly half of all fish used for research and education were wild-caught, should prompt further documentation of such fish uses in order to assess their sustainability. [ABSTRACT FROM AUTHOR]