Blar i Published in cooperation with others på emneord "VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Fisheries technology: 924"
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Comparisons between size distribution in surveys and commercial catches: a useful tool for monitoring changes in the size selection in the fisheries?
(IMR/PINRO Joint Report Series, Conference object, 2001)A method is proposed for using fish distributions from standarized research surveys for estimating relative selection in the fisheries. The method is applied on data for North-east arctic cod in the 1990-ies. Survey-related ... -
Comparisons between size distribution in surveys and commercial catches: a useful tool for monitoring changes in the size selection in the fisheries?
(IMR/PINRO Joint Report Series, Conference object, 2001)A method is proposed for using fish distributions from standarized research surveys for estimating relative selection in the fisheries. The method is applied on data for North-east arctic cod in the 1990-ies. Survey-related ... -
Computerbased detection of schools for counting, quantification of size and swimming behavior by the SIMRAD SA950 sonar
(ICES CM Documents;1993/B:17, Working paper, 1993)As a help in stock assessment of pelagic, schooling fish a software for detection of schools and quantification of their size and swimming behaviour by a high resolution sonar has been developed. The system reads the ... -
Correcting for avoidance in acoustic abundance estimates for herring using a generalized linear model
(ICES CM documents, Working paper, 2006)When a research vessel passes over a herring school or layer, the herring may avoid the vessel by swimming downwards and horizontally. The fish may also change its orientation, which may alter its mean target strength. ... -
Cylindrical sonar design for fish echo surveying
(ICES CM Documents;1988/B:3, Working paper, 1988)Most applications of echo integration involve use of a fixed single-beam transducer that is rather narrow and downwards-oriented. It is often desired to sense fish in other directions, for example, to assess components ... -
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 ... -
Deep towed vehicle for fish abundance estimation concept and testing
(ICES CM Documents;1991/B:53, Working paper, 1991)A research program was initiated in Norway in 1988 for measuring the abundance of fish resources at depth from 500 to 1000 metres. It was decided to develope a deep towed vehicle, to bring acoustic transducers down to ... -
Definition of the problem of estimating fish abundance over an area from acoustic line-transect measurements of density
(ICES CM Documents;1990/D:25, Working paper, 1990)The problem of acoustic abundance estimation is briefly reviewed. Under proper conditions, fish density can be measured with high accuracy along line transects. Observed variations in fish density consequently reflect ... -
Demersal pair trawling and its operational parameters.
(ICES CM Documents;1982/B:36, Working paper, 1982) -
Designing an improved transducer array geometry
(ICES CM Documents;1988/B:2, Working paper, 1988)Improvements in a split-beam transducer that is also used for surveying are sought through changes in array geometry. These are assessed through relative changes in the sum of source level and voltage response and the ... -
Designing an Ocean Mid-trophic Automatic Acoustic Sampler (MAAS) - thoughts on how to include echo sounder observatories in ecosystem models
(ICES CM documents;2009/I:21, Working paper, 2009)Echo sounders are a widely used tool for observing marine ecosystems. Traditionally, carefully designed surveys are used to integrate biomass to a global estimate, which is coupled to traditional stock assessment models. ... -
Detailed in situ target strength measurements of 0-group cod
(ICES CM Documents;1994/B:30, Working paper, 1994)Target strength measurements in situ of cod fry have been made using 38 and 120 kHz split beam echo sounders. Two data sets are sampled in essentially pure, evenly sized, cod concentrations, one in a Ullsfjord, Northern ... -
Detection and counting of individual free-swimming krill using a 2MHz scanning sonar
(ICES CM Documents;1992/L:18, Working paper, 1992)The euphausiid crustacean Meganyctiphanes norvegica (M. Sars) have been detected and counted in the scanning section of a 2 MHz scanning sonar beam up to 3 meters from the sonar head. The tests completes a pilot investigation ... -
Detection of internally tagged fish with special application to the atlanto-scandian herring
(ICES CM Documents;1977/H:20, Working paper, 1977)The paper describes the operating principle and use of a new machine for detection and sorting of internally tagged fish. The machine has been used in the calculation of the Atlanto-Scandian herring stock size. Fixed ... -
Determining the entrance position of fish in trawls
(ICES CM documents, Working paper, 1999)The entrance position of a fish is defined as its two-dimensional position in a cross section of a trawl near the centre of the headline. Individual fish entering the trawl: detected by highresolution scanning sonar, ... -
Development and testing of rope and large meshed midwater trawls in Norway
(ICES CM Documents;1977/B:40, Working paper, 1977) -
Development of a species-selective trawl for demersal gadoid fisheries
(ICES CM Documents;1995/B+G+H+J+K:1, Working paper, 1995)An experiment was carried out to test a prototype species-selective bottom trawl for separating cod from haddock, secondarily saithe, in the Norwegian commercial roundfish fisheries. A sorting system incorporating a ... -
The development of acoustic instrumentation in fisheries research and commercial fisheries in Norway
(ICES CM Documents;1966/F:8, Working paper, 1966) -
Devices to avoid by-catch of birds in longline fishery
(IMR/PINRO Joint Report Series, Conference object, 2001) -
Devices to avoid by-catch of birds in longline fishery
(IMR/PINRO Joint Report Series, Conference object, 2001)