Seasonal distribution and abundance of killer whales around Lofoten and Vesterålen Islands, northern Norway
Working paper
Permanent lenke
http://hdl.handle.net/11250/104994Utgivelsesdato
1992Metadata
Vis full innførselSamlinger
Originalversjon
This report is not to be cited without prior reference to the authorsSammendrag
Killer whales (Orcinus orca) have been pohotoidentified around
Lofoten and Vesterålen islands northern Norway during fall-winter
(October-February) and summer (June-August) in 1990 and
1991. Some background data exists from 1983-1989. To date 302
killer whale individuals belonging to 44 different groups have
been identified. The yearly distribution and abundance of
whales is closely related to the distribution of springspawning
herring (Clupea harengus) in the area. Since 1987
nearly all of the sexually mature herring in this stock spend
the winter in Tysfjord, Ofotfjord and Vestfjord area, and
killer whales are most abundant in the area during this time.
Based on a capture-recapture estimate, about 500 killer whales
are present in the overwintering area of herring. Most of the
whales leave the study area in January when herring migrate to
the spawning grounds 700 km farther south. Five killer whale
individuals have been identified both in the overwintering and
in the spawning grounds of herring. Based on the seasonal
distribution, killer whale groups can be divided into three
different types; whales present in fall-winter ( 25 groups),
whales present both in fall and summer (12 groups) and whales
present in summer (six groups).