Anatoly Petrovich Andriyashev (Russian: Анатолий Петрович Андрияшев; 19 August 1910 – 4 January 2009) was a Soviet and Russian ichthyologist, marine biologist, and zoogeographist, notable for his studies of marine fauna of the Arctic and the Northern Pacific.
Andriyashev focused on ichthyological research in the Far East and the Arctic seas, in the Antarctic and in the different regions of the Pacific, Indian and Atlantic Oceans.
In 1953 he worked on the concept of "ancient deep-water"[note 4] (primitive teleosts which evolved early and dominate the demersal to abysso- and bathypelagic faunas and whose structural adaptation to their habitat include eye and swim bladder modifications and proliferation of light organs e.g. Ceratioidei, Scopeliformes and Saccopharyngiformes) and "secondary deep-water"[note 4] (representatives of a number of common families on the continental shelf with lesser external morphology as a result of later adaptation, e.g. Perciformes) species and, in 1964, on the zoogeographical zonation in the Arctic and Antarctic.
[4] In 1990 he developed the hypothesis of transoceanic (Non-arctic) dispersal of "secondary deep-water" species of boreal-Pacific origin to the depths of the north Atlantic and the Arctic.
In 1979 he studied the problem of vertical zonation salt-water benthic[note 5] ichthyofauna; in 1986, the phenomenon of glacial submergence of the Antarctic ichthyofauna from the subtidal zone to depths of 300–600 metres; in 1970, the justification of the form of cryopelagic fish in ice-covered seas; and in 1997, the conception of bionomic bipolarity of marine life.