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Report of the Working Group on Fish Ecology

Abstract : The Terms of Reference for the Working Group on Fish Ecology are that it will meet in Copenhagen, Denmark, from 3-7 March 2003 to: (a) In preparation for development of objectives and reference levels for EcoQOs related to changes in the proportion of large fish, average weight and average maximum length of the fish community i) analyse trends in these features over time for appropriate survey data sets from the North Sea and other seas ii) evaluate data and trends in other characteristics of fish communities which reflect the same information as in i) iii) where possible identify levels of the properties in i) and ii) that can be taken as indicative of various states of the marine ecosystem (i.e., serve as potential reference levels). (b) Provide an assessment of the data on which the justification of the fish on the OSPAR priority list of threatened and endangered species and habitats will be based. This assessment should be to ensure that the data used for producing the justification are sufficiently reliable and adequate to serve as a basis for conclusions that the fish concerned can be identified, consistently with the Texel-Faial criteria. These fish species are: sturgeon (Acipenser sturio), allis shad (Alosa alosa), houting (Coregonus lavaretus oxyrhinchus), Couch's goby (Gobius couchi), short-snouted seahorse (Hippocampus hippocampus), seahorse (Hippocampus ramulosus) and sea lamprey (Petromyzon marinus). In addition, a last-minute request was made to assess both the loggerhead and leatherback turtles. (c) Review the concept of essential fish habitat and consider what information would be required in order to be able to specify essential fish habitat for individual species or stocks. (d) Initiate for completion in 2003 analyses of: i) ICES data on individual stomach contents as well as other relevant stomach data to obtain estimates of the correction factor k ii) Estimates of food rations of whiting and saithe (feeding primarily on fish) using a prey energy density dependent evacuation model to quarterly mean stomach data iii) the ICES stomach data to acquire possible information about prey composition of individual stomachs. The focus will be on major prey types that deviate significantly in energy density. (e) Initiate for completion by 2004, estimates of food rations of cod and haddock (preying to a large extent on invertebrates with a robust exoskeleton also) using a gastric evacuation model which accounts for the effects of a robust exoskeleton on evacuation of total stomach content as well as of individual prey types. Such a model is expected to be in operation around mid-2003 (f) Review topics of geographic areas where ICES might further contribute to work on rare marine fish species.
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https://hal.inrae.fr/hal-02581409
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Submitted on : Thursday, May 14, 2020 - 9:06:46 PM
Last modification on : Tuesday, September 14, 2021 - 9:54:01 AM

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  • HAL Id : hal-02581409, version 1
  • IRSTEA : PUB00011581

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O.T. Albert, N.G. Andersen, M. Aprahamian, J. Blanchard, N. Daan, et al.. Report of the Working Group on Fish Ecology. irstea. 2003, pp.110. ⟨hal-02581409⟩

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