Blar i ICES CM documents authored by IMR scientists (1949-2011) på emneord "fangstpotensiale"
Viser treff 1-9 av 9
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Density dependent catchability in bottom trawl surveys
(ICES CM Documents;1997/W:16, Working paper, 1997)Fish form schools, layer or patches in which the individual fish's behaviour is not independent of its neighbours movements. On the other hand, at low densities fish may have the freedom to act as single individuals ... -
Diurnal variation in bottom trawl survey catches: does it pay to adjust?
(ICES CM Documents;2001/Q:11, Working paper, 2001)We have studied the diurnal bias of bottom trawl survey catches with the purpose of adjusting for it and thereby improving the accuracy of abundance estimates. The correction term is estimated with uncertainty, and thus ... -
Incorporating experimentally derived estimates of survey trawl catchability into the stock assessment process
(ICES CM Documents;1997/W:5, Working paper, 1997)During the course of the April, 1996, meeting of the Fishing Technology and Fish Behavior Working Group it became clear to many that the methodology for experimentally estimating the catchability of survey trawls might ... -
Measuring the effect of changes in catchability on the variance of marine survey abundance indices
(ICES CM Documents;1992/D:9, Working paper, 1992)The average catch per tow by a research vessel survey is often used as an index of abundance. An estimate of the variance of such indices that is based only on the between station variability in catch may underestimate ... -
Natural fish behaviour and catchability of groundfish
(ICES CM Documents;1994/G:14, Working paper, 1994)Imprecision in estimates of abundance and population parameters obtained from trawl surveys could be reduced if the sources of variability were understood and properly described. Fish behaviour in relation to sampling ... -
Observations on capelin (Mallotus villosus) in Newfoundland waters
(ICES CM Documents;1972/H:12, Working paper, 1972) -
Report of the North Sea roundfish working group [Charlottenlund, 21 - 25 March 1977]
(ICES CM Documents;1977/F:8, Working paper, 1977) -
Studying the relationship between spatial fish distributions and trawl catches
(ICES CM Documents;2004/R:26, Working paper, 2004)We propose an approach for studying the relationship between spatial fish distributions and the distribution of numbers in trawl catches. Individual spatial fish distributions are derived from acoustics data collected with ... -
Vertical distribution of cod, haddock and redfish; Impact on bottom trawl and acoustic surveys in the Barents Sea
(ICES CM Documents;1997/Y:16, Working paper, 1997)At a selected location in the Barents Sea acoustic observations, bottom- and pelagic trawl catch data were collected over a 10 day period. A large proportion of the fish were in the acoustic dead zone during the sampling ...