Browsing Brage IMR by Subject "VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Fisheries technology: 924"
Now showing items 101-120 of 725
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Detecting Atlantic herring by parametric sonar
(Journal article; Peer reviewed, 2010-03-17)The difference-frequency band of the Kongsberg TOPAS PS18 parametric sub-bottom profiling sonar, nominally 1–6 kHz, is being used to observe Atlantic herring. Representative TOPAS echograms of herring layers and schools ... -
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) -
Development of eleven microsatellite loci in the deep-sea black scabbardfish (Aphanopus carbo)
(Journal article; Peer reviewed, 2009-06)We developed 11 microsatellite loci primers in the bathypelagic black scabbardfish (Aphanopus carbo), a novelty for deep-sea fishes. All markers were obtained from partial genomic DNA libraries enriched for tetranucleotide ... -
Development of ten microsatellite loci in the marine fish ling (Molva molva)
(Journal article; Peer reviewed, 2009-09)We developed primers for two dinucleotide and eight tetranucleotide microsatellite loci in a marine fish, the ling (Molva molva). All markers were obtained from partial genomic DNA libraries and characterized in 55 unrelated ... -
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) -
Differences between near bottom biomass spatial structure observed in the Irish Sea, the North Sea and the Barents Sea in recent years
(ICES CM documents, Working paper, 2003)Based on acoustic data and trawl catches collected during bottom trawl surveys, we compare the spatial structure of the biomass available in the first meters above the bottom in three different regions, the Barents Sea ... -
Direct measurements of equivalent beam angle on hull-mounted transducers
(ICES CM Documents;1985/B:43, Working paper, 1985)Measurements for checking the equivalent beam angle on a hullmounted transducer have been made on a standard 38-29/25-E SIMRAD transducer on the Norwegian research vessel "ELDJARN". The measurements were made during a ... -
Directional properties of an 18-kHz transducer
(ICES CM Documents;1993/B:29, Working paper, 1993)Several theoretical measures of directivity are given for an 18-kHz transducer that is used in both single-beam and split-beam applications, namely the SIMRAD transducer type 18-11 in the single-beam variant. These are ... -
Diurnal variation in acoustic densities: why do we se less in the dark?
(ICES CM Documents;2004/R:33, Working paper, 2004)Introduction: In the Barents Sea, the echo abundance of demersal fish is about 50% higher at day than at night. Three possible reasons are: • Fish hide in the bottom dead zone at night. • Fish target strength changes due ... -
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 ... -
Diurnal variation in frequency response of gadoids in the Barents Sea
(ICES CM documents, Working paper, 2006)Earlier studies have demonstrated substantial diurnal variation in acoustic abundance of fish. Both the level and the uncertainty of abundance estimates from surveys carried out around the clock are affected. It has been ... -
Diurnal variation models of bottom trawl survey catches parameterised by using commercial CPUE data
(ICES CM Documents;2004/R:41, Working paper, 2004)Introduction: Diurnal variation is observed in almost all marine surveys and can cause biased abundance and length frequency estimates. Symmetric logistic models developed by Hjellvik et al. (2001) were utilized to ... -
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 ...