Epoques et aires de ponte des poissons téléosteens du Golfe de Gascogne en 1965-1966 (oeufs et larves)

This study is the result of analysing harvests from 1965 and 1966 and is an integral part of the campaigns dedicated to the seasonal study of ichthyoplankton and environmental factors in the Gulf of Gascony. It therefore complements the results acquired for the year 1964 and that are already published (S. ARBAULT, N. BOUTIN, 1968) and is an integral part of a programme the later continuation of which will specify even more knowledge of the various species' egg-laying sites and periods, as well as the ecological laws that govern them, which is an important factor for the scientific forecasting of fishing. For this research work, we would like to thank Mrs. M. L. FURNESTIN who, from the beginning, has never hesitated to give us her advice and help. Six campaigns were conducted by the oceanographic ships Thalassa, La Pélagia and Roselys: in 1965 (figure 1), 4 campaigns with 23 stations in February and May, 22 stations in August, 14 stations in November; the prospected sector is mainly pelagic, many catches were done all along the meridian of 8° O longitude; in 1966, 2 campaigns: in March (94 stations) and in May (99 stations) (figure 2). The samples were taken only on the continental shelf, from the Celtic Sea to the bottom of the Gulf of Gascony. Two sorts of fishing techniques were used: vertical passes using a Hensen net (70 cm in diameter) reeled in between 100 metres and the surface at the rate of 1 metre in 3 seconds (1965 and May 1966); horizontal surface passes for 10 minutes using a standard net, 60 silk, with 30 cm opening (March 1966). The 1966 campaigns, which used both kinds of passes, are difficult to compare because of the selectivity of the passes, the horizontal fishing technique, for example, was more successful in catching eggs that keep to the upper levels than catching larvae, which are distributed at deeper levels.