Utilisation du filet à plancton du type "Bongo"

The "Bongo" net is an American plankton net whose use is coming into general use for studies of ichthyoplankton. Its dimensions and its power of filtration make it an efficient device for researching groups with unevenly spaced micro distribution as well as rare species, especially fish eggs and larvae. It is recommended by the ICNAF (Standard Techniques for Pelagic Fish Eggs and Larvae Surveys) and will soon be recommended by the FAO. The ISTPM, for its part, has been using this net for some years in several campaigns conducted by the Thalassa, the Cryos, La Pélagia, the Roselys and the Ichthys (ISTPM 1971, 1975, ALDEBERT 1975, ARBAULT and LACROIX 1975). In 1975, we decided to use this net in some studies in coastal waters that the ISTPM is conducting in the English Channel and in the southern North Sea. Their goal is to draw up a qualitative and quantitative inventory of all the zooplanktonic populations having a trophic role or halieutic potential in the areas that are about to be modified, either by the setting-up of electronuclear thermal power plants with an open-air cooling system, or by the setting-up of various industries (sand and gravel quarrying, for example).