Blar i ICES CM documents authored by IMR scientists (1949-2011) på emneord "VDP::Mathematics and natural science: 400::Zoology and botany: 480::Ethology: 485"
Viser treff 141-158 av 158
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Surface activity of Atlantic salmon (Salmo salar) in net pens
(ICES CM Documents;1988/F:19, Working paper, 1988)An important feature of the behaviour of salmon is the leaping and rolling activity. These surface activities were studied in fish in net pens in relation to environmental factors and operational procedures. Data were ... -
Survival of saithe (Pollachius virens L.) escaping through trawl meshes
(ICES CM Documents;1992/B:29, Working paper, 1992)A pilot study to estimate the survival of saithe escaping from a cod-end with 145 mm diamond meshes was done in April-May 1992 north of the Faroes. Escaped fish were collected in fine meshed net cages (2x2x5m aluminium ... -
Swimming behaviour of fish schools in the North Sea during acoustic surveying and pelagic sampling trawling
(ICES CM Documents;1990/B:38, Working paper, 1990)Swimming behaviour of schooling herring, mackerel and sprat, when approached by a survey vessel, was observed by aid of a true motion sonar. Observations were made both during surveying and during pelagic trawling. Horizontal ... -
Swimming speed of spent Norwegian spring spawning herring
(ICES CM Documents;1991/H:9, Working paper, 1991)In March 1990 spent Norwegian spring spawning herring were tagged on the spawning grounds off Karmøy in southwestern Norway. 37 of these tagged herring were recaptured approximately 40 hours later. The recapture took place ... -
The challenge of the herring in the Norwegian Sea: making optimal collective spatial decision
(ICES CM Documents;1996/H:15, Working paper, 1996)Herring are long-lived multiple spawners exhibiting strong variation in reproductive and recruitment success between years. They tend to adopt low-risk, preferred-conservative strategies; for example, shifts to alternative ... -
The distribution and abundance of harbour porpoises and other small cetaceans in the North Sea and adjacent waters
(ICES CM Documents;1995/N:10, Working paper, 1995)To provide accurate and precise estimates of abundance for harbour porpoises and other small cetaceans throughout the North Sea and adjacent waters, an intensive shipboard and aerial sightings survey was conducted in ... -
The distribution and abundance of harbour porpoises and other small cetaceans in the North Sea and adjacent waters
(ICES CM Documents;1995/N:10, Working paper, 1995)To provide accurate and precise estimates of abundance for harbour porpoises and other small cetaceans throughout the North Sea and adjacent waters, an intensive shipboard and aerial sightings survey was conducted in ... -
The effective swept volume of a bottom trawl
(ICES CM Documents;2004/R:7, Working paper, 2004)The reaction of individual fish towards an approaching trawling vessel has previously been measured using target-tracking methods. In this paper these measured velocities are fitted to a deterministic mean behaviour ... -
The migration of coastal cod (Gadus morhua L.) tagged in a fjord of western Norway
(ICES CM Documents;1988/G:5, Working paper, 1988)This study is part of a research program investigating the possibility of enhancing the production of coastal cod via a large scale release of pond produced fish in Masfjorden, a fjord of western Norway. An analysis of ... -
The probability of cod (Gadus morhua) and ling (Molva molva) to encounter gillnets based on in situ fish movements
(ICES CM Documents;1997/W:17, Working paper, 1997)The probability of cod (Gadus morhua) and ling (Molva molva) to encounter a fleet of four gillnets (110m) set within a fixed survey area of 600x600 m2 and soaked for a period of 12 h (1800-0600 hrs) is calculated on the ... -
The significance of fish behaviour in the evaluation of hydroacoustic survey data
(ICES CM Documents;1981/B:22, Working paper, 1981) -
The use of data storage tags to study cod natural behaviour and availability to abundance surveys in the Barents Sea
(ICES CM Documents;1997/W:18, Working paper, 1997)Vertical movements of fish stocks can be studied by means of acoustic data from surveys, and diurnal related cycles in behaviour is often reported. To what extent the movements observed by this method reflect behaviour ... -
The use of transplantation-tagging-experiments in studies of migratory diversity of cod off Norway
(ICES CM Documents;1994/Mini:12, Working paper, 1994)Cod along the Norwegian coast show great variability in migration. Coastal Cod may be stationary for the whole life while mature Northeast Arctic Cod migrate long distances to reach the feeding areas in the Barents Sea ... -
Tilt angles of schooling penned saithe
(ICES CM Documents;1985/B:26, Working paper, 1985)Saithe (Pollachius virens) of nearly uniform 32 cm length have been photographically observed during the daytime in an apparently free-swimming and schooling state in a pen of dimensions 90 m length, 10 m width, and 7 ... -
Trawl avoidance as a source of error in estimates of the prevalence of Icthyophonus hoferi disease in Norwegian spring spawning herring (Clupea harengus L.) in the feeding area
(ICES CM Documents;1995/H:8, Working paper, 1995)Summary: Results are presented from a survey in the Norwegian Sea in the summer 1993, where the abundance and distribution of herring was investigated, using a high resolution sonar and pelagic trawling at the surface. ... -
Underwater optics and behavioral responses of krill to presence of fish predators affect fish-plankton interactions
(ICES CM Documents;1993/L:43, Working paper, 1993)In clear oceanic waters off the Norwegian shelf and in outer shelf waters, mesopelagic fish (Maurolicus muelleri) were located at approximately 200 m by day. Across a front into water of lower light penetration, M. ... -
Use of acoustics in studies of fish reaction to imposed stimuli
(ICES CM Documents;1985/B:44, Working paper, 1985)The general distribution pattern of fish in a large holding pen is described through the integrated echo intensity in six separate cells using transducers mounted below the pen. The reaction of fish to different stimuli, ... -
Vulnerability to predation of small cod (Gadus morhua) that escape from a trawl
(ICES CM Documents;1995/B:15, Working paper, 1995)Studies of the vulnerability to gear damage of fish that have been caught in a trawl but have escaped through the codend meshes have focussed on determining survival rates. This study examines the risk of predation in ...