Browsing Published in cooperation with others by Subject "fish behaviour"
Now showing items 1-20 of 103
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A method of observing the spawning behaviour of farmed and wild salmonids in a natural stream habitat
(ICES CM Documents;1993/M:21, Working paper, 1993)When farmed fish escape from farms, they may compete with wild individuals for a number of resources, such as food, spawning sites, and mates. As a part of a larger study on genetic impact from farmed fish on wild ... -
A multiple approach to behaviour studies of salmon reared in marine net pens
(ICES CM Documents;1988/F:15, Working paper, 1988)The behaviour of Atlantic salmon in culture was lnvestigated by various techniques with the ultimate goal of characterlzing the behaviour typical for a situation with rapid growth. Differences in behaviour between and ... -
A new radio link telemetry positioning system, experiences from tracking of fish and crustaceans
(ICES CM Documents;1993/B:23, Working paper, 1993)Telemetry positioning systems based on hydrophone arrays have been used for different tracking applications. The main improvement of this new system is the wire-less transmission of signals from hydrophone - radio buoys ... -
A preliminary review of the joint investigations on the distribution of herring in the Norwegian and Iceland Seas 1950- 1970
(ICES CM Documents;1996/H:14, Working paper, 1996)The paper reviews the joint international investigation of the distribution of the Atlanto-Scandian herring in relation to temperature during the period prior to the collapse of the stock in the late 1960s. The results ... -
A stationary acoustic system for monitoring undisturbed and vessel affected fish behaviour
(ICES CM Documents;1996/B:12, Working paper, 1996)Thorough knowledge of the dynamics of natural fish behaviour and distribution within a survey and among surveys is fundamental for reliability of time series of abundance indices. Further, vessel/trawl affected avoidance ... -
An acoustic survey on 0-group gadoids in the northern North Sea and the Shetland-Orkney area, July 1984
(ICES CM Documents;1985/G:17, Working paper, 1985)An acoustic survey was carried out by two research vessels in July 1984 to assess the distribution and abundance of 0-group gadoids. The 0-groups were distributed in scattering layers by night and in schools by day. ... -
Avoidance reactions of ultrasonic tagged cod during bottom trawling in shallow water
(ICES CM Documents;1991/B:41, Working paper, 1991)Introduction: Observations made by echo sounder (Ona 1988) have shown that cod (Gadus morhua L.) may avoid an approaching survey vessel horizontally and vertically. However, there has been a lack of information on the ... -
The behaviour of whiting (Gadus merlangus) in relation to long lines
(ICES CM Documents;1977/B:44, Working paper, 1977) -
Behavioural rhythm of cod during migration in the Barents Sea
(ICES CM Documents;2000/K:34, Working paper, 2000)To assess fish abundance by direct methods and to understand and model species interaction, it is important to have proper knowledge about behavioural patterns. Patterns in vertical distribution might strongly affect ... -
Changes in acoustic abundance - a signal indicatior for stock dynamics for cod (Gadus morhua)
(ICES CM documents, Working paper, 1999)To be able to take the proper and timely management actions, it is crucial to reliably defect major changes in trends of fish stock abundance. For the assessment of Northeast Arctic cod, the Norwegian bottom trawl survey ... -
Comparative habitat use and foraging behaviour of harbour seals and grey seals in Western Norway
(ICES CM Documents;1995/N:1, Working paper, 1995)Adult harbour seals at Froan nature reserve, Central Norway, were tagged with VHF radio tags and depthvelocity, hart rate and stomach temperature sensors combined with ultrasonic transmitters. An automatic shore based ... -
Day / night variation in fish directivity in the trawl opening
(ICES CM Documents;1994/B:18, Working paper, 1994)Still photographs of fish in the mouth area of a bottom trawl were taken by a downwards-oriented automated strobe camera mounted near the headrope. Fish angles relative to the towing direction were measured. Fish were ... -
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 variations in acoustic density measurements of wintering Norwegian spring spawning herring
(ICES CM Documents;1995/B:12, Working paper, 1995)Survey data from six herring assesment cruises in the wintering areas for spring spawning Norwegian herring were analysed with regard to variation in abundance and depth with time of day. The data were quite consistant ... -
Diving observations on Barents Sea capelin at its spawning grounds off the coast of northern Norway
(ICES CM Documents;1971/H:25, Working paper, 1971) -
Dynamics of moving masses: Variability in packing density and shape among pelagic schools
(ICES CM Documents;1990/B:40, Working paper, 1990)The packing density and external shape of herring, saithe and sprat schools in the North Sea and along the Norwegian coast are measured acoustically. The packing density was inversely. related to the fish size, but species ... -
Effect of swimming on fish target strength
(ICES CM Documents;1985/B:29, Working paper, 1985)The influence of the swimming movement on fish target strength is investigated through a modelling exercise. In this, several gadoid specimens are represented as acoustic scatterers through their triangulated swimbladder ... -
Engineering and fish reaction aspects of gillnetting - a review
(ICES CM Documents;1981/B:34, Working paper, 1981) -
Engineering and fish reaction aspects of longlining - A review
(ICES CM Documents;1981/B:35, Working paper, 1981) -
Extensive gas bubble release in Norwegian spring spawning herring (Clupea harengus) during predator avoidance
(ICES CM Documents;1998/J:20, Working paper, 1998)Events of extensive gas bubble releases in overwintering Norwegian spring spawning herring (Clupea harengus) were repeatedly observed acoustically and visually in Vestfjorden, northem Norway, during attacks from killer ...