Trans-Atlantic Study of Calanus: Large Scale Field Survey

The objective of this subtask of the Trans-Atlantic
Study of Calanus programme was to describe the large
scale distribution, abundance, and population structure
of C. finmarchicus in the Nordic Seas for the summer and
winter seasons, and assess the genetic cohesiveness of
C. finmarchicus.

Summer distributions of C. finmarchicus were determined
by sampling with MOCNESS, BIONESS or MULTINET multiple
sampling systems and WP-2 nets, and by acoustical mapping
with shipborne echo sounders (38, 120, 200 kHz). Supporting
information on hydrography (CTD), phytoplankton development
(nutrients, chlorophyll, in situ fluoresence), zooplankton
size-fractioned biomass, and distribution and abundance of
fish (acoustics, pelagic trawl) were collected by
continuous recording and vertical profiling.

This study of genetics used the frequencies of different
alleles of several genes to describe population structure.
Allelic variation of the genes will be determined by
variation in the DNA sequence of a portion of each gene
for individual copepods. DNA was extracted from individual
copepods. A region of mitochondrial DNA will be amplified
using polymerase chain reaction (PCR) technology (Innis et
al. 1990). Specific techniques are described in Bucklin and
Kann (1991) and Stanton et al. (1992). Amplified DNA will
be sequenced, and sequences will be alligned to those of
other individuals of C. finmarchicus from the Norwegian Sea.

The DNA sequencing will be carried out at University of
Bergen where we have access to an Automated DNA Sequencer.
The frequency of each sequence variant in each region will
be determined. Standard population genetic analyses of
population structure based on allele frequencies will be
done to determine whether the species is significantly
structured in the Norwegian Sea.

Cruise: June 19 - July 16, 1997 RV Johan Hjort
(Institute of Marine Research, Bergen)