Blar i ICES CM documents authored by IMR scientists (1949-2011) på forfatter "Bjordal, Åsmund"
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A multiple approach to behaviour studies of salmon reared in marine net pens
Fernö, Anders; Furevik, Dag M.; Huse, Ingvar; Bjordal, Åsmund (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
Bjordal, Åsmund; Engås, Arill; Soldal, Aud Vold; Øvredal, Jan Tore (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 ... -
Capture techniques for wrasse (Labridae)
Bjordal, Åsmund (ICES CM Documents;1993/B:22, Working paper, 1993)An increasing demand for wrasse used as cleaner-fish for louse control in salmon farming has led to a new fishery for different wrasse species - particularly goldsinny, rock-cook and corkwing wrasse. This paper describes ... -
Cleaning symbiosis between wrasses (Labridae) and lice infested salmon (Salmo salar) in mariculture
Bjordal, Åsmund (ICES CM Documents;1988/F:17, Working paper, 1988)Epidemic infestation by the crustacean ectoparasitic salmon lice (Lepeophteirus salmonis) is a major problem in marine salmon farming. Cleaning symbiosis between different labrid species and lice infested salmon is ... -
Effect of attractant distribution on catch rate and size selection of Norway lobster caught by pots
Bjordal, Åsmund; Løkkeborg, Svein; Skeide, Roar L. (ICES CM Documents;1991/B:45, Working paper, 1991)In comparative fishing trials with Norway lobster (Nephrops norvegicus) pots, the attractant property of an aqueous extract of mackerel was tested against that of natural mackerel bait. The catch rate of the natural ... -
Effect of different long-line baits (mackerel, squid) on catch rates and selectivity for tusk and ling
Bjordal, Åsmund (ICES CM Documents;1983/B:31, Working paper, 1983) -
Effects of trawling and longlining on the yield and biomass of cod stocks - numerically simulated
Bjordal, Åsmund; Laevastu, Taivo (ICES CM Documents;1990/G:32, Working paper, 1990)Numerical studies were conducted on the effects of trawl and longline catches on a cod stock and possible yields from it. Five year mean age composition of Pacific cod (Gadus macrocephalus) from the Bering Sea was used ... -
Effects on salmon (Salmo salar) from different operational procedures in fish farming
Bjordal, Åsmund; Fernö, Anders; Furevik, Dag M.; Huse, Ingvar (ICES CM Documents;1988/F:16, Working paper, 1988)The effects on farmed salmon caused by operational procedures as handling, de-lousing, removal of dead fish, grading and transfer were studied by underwater TV-observations, ultrasonic telemetry of heart rate and analyses ... -
Engineering and fish reaction aspects of longlining - A review
Bjordal, Åsmund (ICES CM Documents;1981/B:35, Working paper, 1981) -
Full scale fishing trials for tusk (Brosme brosme) and cod (Gadus morhua) with a collapsible fish trap
Bjordal, Åsmund; Furevik, Dag M. (ICES CM Documents;1988/B:33, Working paper, 1988)A collapsible fish trap with low weight and low stacking volume has been developed and tested in full scale fishing operations. The catch rates of tusk were promising, while the catches of cod were too low and variable ... -
Full scale tests of improved longline gear
Bjordal, Åsmund (ICES CM Documents;1985/B:45, Working paper, 1985)A new type of bottom set longline was tested in trials during the cod fishery off Finnmark November-December 1984. This gear differed from traditional longloine, by being rigged with swivel-mounted monofilament gangions ... -
Improved catch rates and selection of Norway lobster (Nephrops norvegicus L.) by controlled release of fluid bait extract in pot fishing
Bjordal, Åsmund; Løkkeborg, Svein (ICES CM Documents;1992/B:14, Working paper, 1992)The effect of controlled release of fluid mackerel extract as bait in Norway lobster pots was tested in comparative fishing trials. Compared with natural mackerel bait, pots with extract release rates above 6 ml/h had ... -
Longline: Full scale trials with new hook designs and reduced size of bait
Bjordal, Åsmund (ICES CM Documents;1983/B:32, Working paper, 1983) -
Size selective effects of a plastic body on longline hooks
Løkkeborg, Svein; Bjordal, Åsmund; Skeide, Roar L. (ICES CM Documents;1991/B:46, Working paper, 1991)The potential for improving size selectivity of longlines by using a plastic body attached to the hook shank was tested in a fishing trial for tusk (Brosme brosme), ling (Molva molva) and haddock (Melanogrammus aeglefinus). ... -
Surface activity of Atlantic salmon (Salmo salar) in net pens
Furevik, Dag M.; Huse, Ingvar; Bjordal, Åsmund; Fernö, Anders (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 ... -
Swivel connected gangions in mechanized longlining - effect on cath rates and operation
Bjordal, Åsmund (ICES CM Documents;1987/B:18, Working paper, 1987)Multifilament longline with swivel connection between gangions and mainline were compared with traditionally rigged gear on a vessel equipped with a mechanized longline system. The swivel-lines were adapted to the ... -
Synergistic effects of different baits on the same hook in the longline fishery for hake (Merluccius merluccius) and torsk (Brosme brosme)
Franco, Jose M.; Bjordal, Åsmund; Løkkeborg, Svein (ICES CM Documents;1987/B:39, Working paper, 1987)The effects of a combination of different baits on the same hook were tested in two different situations. A bait combination of sardine (Sardina pilchardus) and mackerel (Scomber scombrus) was used to catch hake (Merluccius ... -
Tagging of saithe (Pollachius virens L.) at a Norwegian fish farm : preliminary results on migration
Bjordal, Åsmund; Skar, Anne Brit (ICES CM documents, Working paper, 1992)Wild fish, particularly saithe (Pollachius virens L.) are commonly observed in the vicinity of fish farm sea cages on the Norwegian west coast and the fish are known to feed on excess salmon food pellets. To investigate ... -
Testing of a new hook design (E-Z-Baiter) through comparative longline fishing trials
Skeide, Roar L.; Bjordal, Åsmund; Løkkeborg, Svein (ICES CM Documents;1986/B:25, Working paper, 1986) -
Testing of a new hook design in the longline fishery for tusk (Brosme brosme) and ling (Molva molva)
Bjordal, Åsmund (ICES CM Documents;1987/B:20, Working paper, 1987)The EZ-Baiter Circle hook which is a hybrid design between the classical J- and Circle hook shapes, is developed to provide a more effective hook for use in mechanized longline systems. In comparative fishing trials, ...