Скачать или смотреть Imants G. Priede: Deep-sea fishes: discovery, distribution, origins and diversity

Imants G. Priede, University of Aberdeen, gave a lecture titled "Deep-sea fishes: discovery, distribution, origins and diversity" at FishBase Symposium 2018 in Stockholm, Sweden, on 15th October, 2018.

ABSTRACT: Deep-sea fishes were first described scientifically by Antoine Risso (1810) with an account of their depth zonation in the Bay of Nice although some species were listed by Linnaeus (1748) but with no depth information. The circum-global voyage of the research ship Challenger (1872 – 1876) showed that fishes occur at great depths in all the oceans and the Valdivia expedition (1898 – 1899) confirmed presence of pelagic species throughout the water column from the surface to the abyss.

There are probably about 3800 species deep-sea fish. Numbers decrease with depth; Myxini down to 3003 m, Chondrichthyes to 4156 m and Actinopterygii to 8370m.

Generally, deep-sea families originated by colonisation from shallow waters, with ancient deep-sea endemic families having lost their shallow-water representatives and more recent secondary or invasive groups retaining a continuous distribution from shallow-waters to the abyss and beyond. For some groups, (e.g. Chimaeriformes, Squalimorphi and Rajidae) the deep-sea has acted as a refuge during mass extinction events. The Gadiformes appear to have originated in the deep-sea and have recently colonised shallow seas and continental shelves.

The deep-sea fish fauna is not a distinct taxonomic group but is the result of opportunistic colonisation from the numerous branches and twigs of evolutionary tree of fishes. The present-day fauna is dominated by forms that have originated over the last 100 million years since the mid-Cretaceous, coinciding with the break-up of Pangaea and opening of the Atlantic Ocean with modern global circulation.