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Comparative character of the deep‐water and inshore cottoid fishes endemic to Lake Baikal
Author(s) -
Sideleva V. G.
Publication year - 1996
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.1996.tb06076.x
Subject(s) - abyssal zone , biology , pelagic zone , plankton , bathyal zone , ecology , deep sea , waves and shallow water , oceanography , hydrostatic pressure , endemism , deep water , fishery , benthic zone , geology , physics , thermodynamics
Lake Baikal's 29 endemic species of cottoid fishes form three groups: shallow‐water species in depths to 350 m; eurybathic species from 50 to 1300 m; and abyssal species from 400 to 1600 m. These groups differ in their abilities to withstand high hydrostatic pressure. As in marine deep‐water fishes, abyssal cottoids in Baikal have few or no cones in the retina, and some have tubular eyes. Their seismosensory systems predominate, based chiefly on free neuromasts. The proportion of species with canal systems decreases with depth. Diversity of the predominantly gammarid foods also decreases from 45 species in shallow water to five species in deep water, and the lateral line system plays the dominant role in food detection at all depths. Two abyssal cottoids have become secondary pelagic, achieving close to neutral buoyancy through high lipid levels and reduced skeletal mineralization. These forms take advantage of the abundant pelagic planktonic amphipod populations. The adaptations of abyssal forms parallel those seen in deep‐water marine fishes.