Amphi-Pacific Distribution of Organisms

Amphi-Pacific Distribution of Organisms 

the divided (separated) distribution of aquatic organisms of various subspecies or similar species in the northern half of the Pacific Ocean. The organisms are encountered, on the one hand, in the Pacific in the waters along the Asian continent and, on the other, along the American shores, but not in the open part of the ocean—in its tropical zone—or in the north along the coasts. Amphi-Pacific distribution is characteristic only of a small portion of the Pacific fauna, but the total number of species with an amphi-Pacific distribution is rather significant and includes the Pacific sturgeon, sardine, anchovy, mackerel, certain flounders, sponges, decapods and isopods, echinoderms, and so forth. Amphi-Pacific distribution is usually explained by the migration of the animals from east to west or vice versa during warmer periods—the Pliocene and interglacial periods—and by the subsequent breaking of their range as a result of recent drops in the temperatures of the Sea of Okhotsk and the Bering Sea.

REFERENCE

Zenkevich, L. A. Biologiia morei SSSR. Moscow, 1963.

V. G. GEPTNER