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Abbott C.L.,Northwest Atlantic Fisheries Center
Current Biology

DNA-based methods continue to unveil the diversity and evolutionary origins of life on Earth. 'Next generation' methods have just solved a long-standing puzzle by uncovering previously unseen yet globally distributed diversity within a lineage of amitochondriate parasites affecting commercially exploited aquatic hosts. This discovery will impact both pure and applied research fields. © 2014 Elsevier Ltd. Source

This study is a description of sediment sulphide levels and redox potential associated with different values of bacterial mats (Beggiatoa) coverage at stations in deep Subarctic finfish sites. Beggiatoa was not observed at reference stations and significant differences were found between geochemical parameters before aquaculture and at-harvest. Beggiatoa coverage should be considered in the light of other evidence gathered through video imaging such as benthic diversity and the presence of other visual indicators and not used as strict regulatory thresholds. © 2014 International Council for the Exploration of the Sea. All rights reserved. Source

Rice J.C.,Northwest Atlantic Fisheries Center | Garcia S.M.,FAO Fisheries Management Division
ICES Journal of Marine Science

This paper reviews global projections to 2050 for human population growth and food production, both assuming constant climate and taking account of climate-related changes in growing conditions. It also reviews statistics on nutritional protein requirements, as well as how those requirements are met by fish on a regional basis. To meet projected food requirements, the production of fish has to increase by ∼50 from current levels. The paper also summarizes the main pressures on marine biodiversity that are expected to result from the impacts of changing climate on marine ecosystems, as well as the management measures and policy actions promoted to address those pressures. It highlights that most of the actions being proposed to address pressures on marine biodiversity are totally incompatible with the actions considered necessary to meet future food security needs, particularly in less developed parts of the world. The paper does not propose a solution to these conflicting pulls on policies for conservation and sustainable use. Rather, it emphasizes that there is a need for the two communities of experts and policy-makers to collaborate in finding a single compatible suite of policies and management measures, to allow coherent action on these crucial and difficult problems. © 2011 International Council for the Exploration of the Sea. Source

This study evaluated the distribution of major calanoid copepods in the western Labrador Sea in relation to that of the myctophid Benthosema glaciale, and investigated patterns of prey composition and feeding periodicity by the latter to assess the potential impact of mesopelagic fish on copepod populations that reside in the deep ocean. Hydroacoustic surveys indicated that B. glaciale and the deep-scattering layer are widely distributed throughout the region with limited evidence of patchiness, with an average abundance of 6 fish m-2 and biomass of 9.3gm-2. There was clear evidence of diurnal variations in feeding activity that was achieved through vertical migration from several hundred meters depths to the surface layer. B. glaciale fed principally on calanoid copepods, with prey size dependent on the length of the fish but the relative variability in prey size was independent of predator length. Average rations were generally less than 1% of body weight per day, and the patterns of diurnal vertical migration by myctophids suggest that individuals fed once every two days rather than daily. The estimated mortality caused by B. glaciale on the calanoid populations, which considers most sources of uncertainty, ranged from 0.002 to 1.8% d-1, with the mid-point of these estimates being ~0.15% d-1, which is well below the estimated mortality rates of 10-20% d-1 based on vertical life tables. From observations from this and other ecosystems, understanding and contrasting the drivers of population dynamics and productivity of calanoid copepods in different deep basins of the North Atlantic will likely require a more comprehensive characterization of the plankton and pelagic and oceanic fish faunas of the epipelagic and mesopelagic zones and their trophic relationships and interactions. © 2013. Source

Rice J.,Northwest Atlantic Fisheries Center
Fish and Fisheries

The four general components of an ecosystem approach to fisheries (EAF) are reviewedIn taking account of environment forcing in stock dynamics, arguments are presented that effects of environmental forcing on growth, maturation and natural mortality are often more important to management than effects on recruitmentIn holding fisheries accountable for the ecosystem effects of fishing, it is argued that direct effects of fishing are generally known and can be managedHowever, interactions among fisheries and between fisheries and other sectors pose difficult challenges to equitable decisions in managing these impacts, and many traditional incentives function differently in EAF than in target-stock managementAchieving inclusiveness in decision-making and stewardship is also made more complex in EAF, because of the much larger number of interests with a legitimate role in decision-makingAs a result, integrated management (IM) becomes a necessary component of EAF, although EAF and IM are not interchangeable conceptsThe treatment of all four components of an EAF considers the need for a balanced and stable outcome on all three dimensions of sustainability - ecological, economic and socialIt also highlights that different participant groups in governance display different risk tolerances for misses (not taking conservation action when needed) and false alarms (restraining access to social or economic benefits when little ecological benefit results)These differences in tolerances for different kinds of management errors often complicate decision-making an EAF setting and raise transaction costs greatly. © 2011. Source

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