Biological Oceanography

Euphausia   superba:    Euphausiid

Fig. 10.9 The distribution pattern (filled circles) of Calanoides acutus at stations (all
circles) sampled by the Discovery Expeditions. This is a copepod mostly confined to
south of the Antarctic convergence.

(^) (After Andrews 1966.)
There are some distributions that do not fit exactly. Euphausia gibboides is an
example; it is distributed in the southern sector of the transition zone and in the
eastern tropical Pacific, with a definite and wide gap between them. Like most odd
patterns, it is a combination of two usual patterns. Nishida (1985) has given us an
example (Fig. 10.10) of a distribution with extreme latitudinal extent, the pattern for
Oithona similis, a small copepod. Its pattern includes the subarctic Pacific, the
California Current (our observations), the eastern tropical Pacific, the Peru Current,
and the subantarctic. This pattern makes sense over most of its extent in terms of
water temperatures available fairly close to the sea surface, <∼300 m.