The egg production of Arcto-Norwegian cod (Gadus morhua L.) in the Lofoten area estimated by egg surveys
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Date
1984Metadata
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- Symposium proceedings [168]
Abstract
Spawning intensity measurements have been executed in Lofoten
each year since 1976. They consist of egg net samples at selected
spawning cites . In 1983, in addition, four quasi-synoptic egg
surveys were conducted during the spawning ceason coverinq the
total spawning area in Lofoten. These data are used to estimate
the egg production during the spawning season 1983. The estimates are done by two methods. In the first method stage 1, 2
and 3 cod eggs a r e used i n eaeh survey t o qet 3x4=12 estimates
of the egg production per day at different t imes during the
spawning season. The 1 2 values are used to construct an egg
production curve for the spawning season. The curve is integrated to get an estimate of the total egg productian. By the
other method certain assumptions about the egg distribution
field have to be done, and the total egg production is computed
by combining the spawning intensity data with one quasi-synoptic
survey. The first method is the most correc tone. The second
method is more rapid and needs less ships time and time for egg
analysis. It is discussed how to get the second method more
accurate.
Description
The proceedings of the Soviet-Norwegian symposium on: Reproduction and recruitment of Arctic cod. Leningrad 26 - 30 September 1983.
Series
PINRO-IMR Symposium1