Fróðskaparrit - 01.01.1987, Page 73

SPAWNING OF ATLANTIC HALIBUT
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Fig. 1. The main research area (hatched) south west of the Faroes. On the detailed map are shown bottom topo-
graphy, the protected halibut spawning area (stipled), the CTD-stations (black dots), and the track of the trawl on
16 February when large variations in bottom temperatures occurred (Fig. 8).
in winter or early in spring (Jákupsstovu &
Haug 1987). This paper presents further re-
sults form these investigations including
variations in the frequency of mature fish
and in the size/age distributions in relation
to depth and time of the year, the occur-
rence of planktonic eggs, and the hydro-
graphic regime under which the halibut
spawns and eggs develop in the area.
Material and methods
The fish were caught in bottom trawls by
r/v »Magnus Heinason«. Three different
commercial bottom trawls were used: One
four paneled and two two-paneled. There
was no apparent difference in the trawls
ability to catch halibut. Trawling took
place in 1983 (November and December),
1984 (January), 1985 (January and Febru-
ary), 1986 (January and February) and
1987 (February), mainly in the deep water
halibut spawning area on the continental
slope northwest of the Faroe Bank, but se-
veral hauls were also made in shallower
waters on the banks and coastal waters
around the Faroes (Fig. 2). The material
from all years was pooled, while fish from
the shallower hauls (<700 m) were treated
separately from those from the deepest
(>700 m) hauls.