(^) Gulf of Alaska pollock (Theragra chalcogramma) meet in March–April for a
mating spree just to the northwest of Kodiak Island over a shelf trench adjacent to
Cape Kekurnoi on the Alaskan Peninsula. Eggs sink to about 150 m and are not
advected much during 2 weeks of development. On hatching, the larvae ascend to the
upper 50 m, drifting southwest in the Alaska coastal current, often in patches and
often entrained for a time in back-eddies, as they feed in the plankton-rich Shelikoff
Strait, growing at ∼2 mm d−1 through May. There are other pollock stocks associating
at other spawning sites and times, particularly one on the eastern end and seaward
edge of the Bering Sea shelf in May.
(^) Atlantic cod (Gadus morhua) generally have about a dozen major and many minor
spawning sites (Brander 1997; Fig. 17.1a), from Lofoten in Norway to Georges Bank,
where breeding groups gather for relatively short spawning seasons. For example, cod
from all over and around Georges Bank move to the northeast peak of the bank (Fig.
17.1b) to spawn in late February. In February–March, Calanus finmarchicus
(copepod) adults that are ready to spawn will accumulate over this site, and their
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