New patterns of diurnal vertical migration of some deep-water copepods in the Tyrrhenian and Adriatis Seas

✍ Scribed by J. Hure; B. Scotto di Carlo

• Publisher: Springer-Verlag
• Year: 1974
• Tongue: English
• Weight: 507 KB
• Volume: 28
• Category: Article
• ISSN: 0025-3162
• DOI: 10.1007/bf00387295

✦ Synopsis

The diel vertical migration of copepods from intermediate water layers of the Tyrrhenian and Adriatic Seas has been studied on the basis of plankton samples made from depths down to 1000 m, with a Nansen net, mesh size 250 ~, diameter 113 cm. The species considered display two different patterns of migration: (1) nocturnal ascent, e.g.

Pleuromamma abdominalis and Euchaeta acuta;

(2) nocturnal descent, e.g. species of the genera Spinocalanus, Scaphocalanus, Temoropia, Mormonilla and Oncaea. These two patterns are compared on the basis of the dimensions of the species and of their different capacities for active movement. Illumination is considered to be the most important factor influencing vertical movements. The behaviour of Pleuromamma gracilis is also described, the adult population of which is divided in two discrete sections, each one showing a different pattern of migration.