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SUMMARY: In this study, the results obtained from three experimental trap shrimp (Plesionika edwardsi) fishing cruises in three different seasons are presented. They were carried out during a total of 50 days, of which 43 days were of effective fishing, covering the whole Spanish Mediterranean coast including the island of Alborán. On the whole, the fishing depth varied between 220 and 384 m, with a mean depth of 318 m. The target species appeared in 81% of the total samples carried out, with a mean yield (cpue) of 108.6 g/trap/day. The largest yields (cpue) of this species were from the Balearic islands, followed by Levant region, whereas the Alborán sea gave the lowest yields. The largest mean length was observed on the Levant zone, but on the contrary the smallest mean lengths were found towards the south, more specifically at Alborán island. Significant differences were found in both the relative and absolute growth, between males and females, with equilibrium in the ratio of the sexes (0.49). A total of 15 crustacean and 12 fish species were identified as accompanying fauna, with Conger conger, Plesionika narval and Scyliorhinus canicula being the most important, based on their mean cpue, although differences in the appearance and yields of the species were found in the different zones and depths. However, the mean yields of these species were very low, due to the high selectivity of the fishing gear used. The appearance of Heterocarpus ensifer, deserves a special mention, since it is the second documented record of the species in the Mediterranean.

The study area for this work includes all the southern edge of the Bay of Biscay, from the north-west Iberian Peninsula to the southern half of the French shelf. The principal aim of this article is to provide a complete overview of the physical oceanography of the area, mainly in its mesoscale aspects, of which there are few published studies, and the implications for early fish life history stages. The results showed the existence of two space and temporal scales for most of the physical processes that occur in the Bay of Biscay, a macroscale for seasonal time periods and a meso and submesoscale for the periods between seasons. The importance of local phenomena, such as upwelling or the variability of the Poleward Current, was observed. The interaction of both scales on these physical processes is discussed and the need for sampling at the submesoscale level to determine the distribution of ichthyoplankton is considered. Moreover, the mesoscale physical oceanography study is essential to improve the knowledge of interactions between strategies and environmental conditions that result in a significant mortality reduction in fish early stages.

The annual cycle of temperature, salinity and nutrients of surface waters (up to 100 m depth) was studied from June 1991 to December 1995 in a cross-shelf section over the continental shelf waters off Santander (southern Bay of Biscay). The time se:ries showed that the temperature followed the expected seasonal. warming and cooling pattern, which determines a seasonal process of stratification and mixing of the water column. The stratification period occurs annually between May and October in a layer of about 50 m depth from the neritic station be:yond to the shelf-break. In the period between November and April the water column remained mixed. During spring and summer low salinity values were found in the surface due to continental runoff and advection from oceanic waters. In late autumn and winter, the salinity pattern was governed by an influx of salty water associated with the poleward current. As in other temperate latitudes, nitrates showed the highest values in winter throughout the water column and the lowest values at the surface during the stratified period. Wind-induced upwelling events were observed mainly in summer, which are characterised by low temperatures (< 12 "C), high salinity and nutrient concentrations. The inter-annual variability of temperature showed a warming trend in the upper layers but this sign was not found at 100 m depth. In salinity a decreasing trend was observed throughout the water column, and this feature corresponds to the relaxing of the high salinity anomaly detected in the North Atlantic at the beginning of the 1990s. Both trends were coherent in the cross-shelf section from the coast to the slope. 0 Elsevier, F'aris Bay of Biscay I hyldrographical conditions I surface water I time series