Copepoda
Vertical distribution

The geographic distribution of pelagic animals is closely linked with their bathymetric distribution. The habitat of pelagic copepods may be subdivided into the following vertical zones: 0-200 m: epipelagic; 200-750(1000) m: mesopelagic; 750(1000)-3000 m: bathypelagic, and deeper than 3000 m: abyssal (Vinogradov, 1968) (Zonation).

Species and even taxa of higher rank may be strongly connected with a certain layer. For example, in the South Atlantic Nannocalanus minor, Undinula vulgaris, Subeucalanus subtenuis, Subeucalanus pileatus, Paracalanidae, all Clausocalanus species, Euchaeta marina, Pontellidae, Temora turbinata are conspicuous members of the epipelagic copepod fauna. They remain in the uppermost layers all their life. On the other hand, Megacalanidae, Bathypontiidae, Pseudochirella (Aetideidae), Paraeuchaeta, Valdiviella (Euchaetidae), the majority of Spinocalanidae and other meso- or bathypelagic species avoid the uppermost layers. However, our knowledge of vertical distributions is often incomplete and those that are better known do not conform exactly to particular depth classifications. Many copepods migrate vertically and may be found at different depths at different times of the day, in different seasons, at different latitudes, and at different developmental stages.

A number of species are recorded from Brazilian coastal and slope waters which are interpreted to live in association with the sea floor. These species belong to the families Aetideidae, Phaennidae, Scolecitrichidae, Diaixidae, Tharybidae, Mesaiokeratidae, and Arietellidae (see tables on page Co.12 Tables. Morphometric and distributional data for the species treated). A few epipelagic copepod species inhabit the neustonic environment and live in close association with the thin film at the very sea surface (Champalbert, 1980). These species almost exclusively belong to the Pontellidae (e.g. Turner et al., 1979; Champalbert, 1985; Ohtsuka, 1985) although other copepods may be found in this environment (Hattori et al., 1983; Nair et al., 1989). Such copepods may be further subdivided according to their degree of attachment to the sea surface (Matsuo and Marumo, 1982).