Now showing items 1-10 of 1408
(Journal article, 1990)
Ekkoloddsvinger i pendeloppheng
(Journal article, 1972)
The surface layer, 0-15 m, will as a rule not be satisfactorly covered by ordinary hull mounted vertical echo sounder transducers. A side looking transducer has been tried onboard the R.V. "G. O. Sars". The transducer is ...
Norsk-arktisk torsk: Forskartal, feil og fangstkvote
(Journal article, 1997)
Observing individual fish behavior in fish aggregations: Tracking in dense fish aggregations using a split-beam echosounder
(Journal article; Peer reviewed, 2007)
Acoustic instruments are important tools for observing the behavior of aquatic organisms. This paper presents a simple but efficient method for improving the tracking of closely spaced targets using a split-beam echosounder. ...
Comparison of walleye pollock target strength estimates determined from in situ measurements and calculations based on swimbladder form
(Journal article; Peer reviewed, 1988)
The target strength of walleye pollock (Theragra chalcogramma) at 38 kHz has been determined in each of two ways: (1) in situ measurement with dual-beam and split-beam echo sounders, and (2) theoretical calculation based ...
Correcting acoustic measurements of scatterer density for extinction
(Journal article; Peer reviewed, 1990)
Extinction is sometimes a major problem in acoustic surveys of fish stocks, as it often occurs when the fish are concentrated and easiest to survey. The same may be true of certain macrozooplankton, such as krill in swarms. ...
Plankton succession and responses to manipulations in a marine basin for larval fish rearing
(Journal article; Peer reviewed, 1991-08-08)
A marine basin was constructed in order to provide fish larvae a natural environment for growth and survival. In nature, similar enclosed systems are limited by stagnant water and anoxic conditions. Consequently, 3 types ...
Spatial shifts in spawning habitats of Arcto-Norwegian cod related to multidecadal climate oscillations and climate change
(Journal article; Peer reviewed, 2008-06-02)
Arcto-Norwegian cod tend to produce strong year classes in warm years and poor year classes in cold years. This work shows that spawning intensity at various spawning sites along 1500 km of Norwegian coast is also influenced ...
Syndebukk og sanning
(Journal article, 1988-11)
Averaging of fish target strength functions
(Journal article; Peer reviewed, 1980)
A general model for averaging the acoustic target strength functions of fish is stated in calculable form. It accounts for the influences of the distribution of generally coupled spatial and orientation states of fish, ...