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Obituary: Pascal Divanach (1949-2021).

The continuous on-line meeting of metabolic demand via feed supply is an important factor for successful aquaculture. This factor is more acute for small larvae, which have a relatively high metabolism, implicating a long photophase and continuous feeding. Such requirements can not be easily met using classic manual feeding methods due to logistic problems. A computerized system has been developed for feed management in intensive hatcheries. The daily plankton requirements of larvae, organized in feeding tables together with a distribution pattern, was used for the development of the required hardware and software to control feeding. The system computes the food required (plankton organisms) and activates a peristaltic pump and solenoid valves for distribution to tanks. The system offers the option of feeding either according to tables or manually, depending on the concentration of plankton in the rearing tanks. Feeding is programmable for 24-h periods. A pilot scale application gave comparable results from a biological perspective and improved management when compared with standard methodologies. Four populations of sea bream (Sparus aurata) were reared with the pseudo-green water intensive method using the automated feeding system and two were reared using a standard technique. Larvae in both cases reached a total length of 10.73±0.77 mm in 30 days post hatching with survival varying between 41 and 51% without differences between the conditions tested. In terms of management, the labor requirement for feeding was reduced by 30–40% with the use of the automated feeding system while the utilization of Artemia nauplii was reduced by 40%. Feeding data as well as information concerning growth of the larvae and the evolution of the rearing were collected in a database. The system is compatible with other software packages for data collection and retrieval.

International audience; Chronic ulcerative dermatopathy (CUD) also known as chronic erosive dermatopathy, hole-inthe- head, head and lateral line erosion syndrome (HLLE) and lateral line depigmentation (LLD) is a chronic disease of unknown aetiology that affects the lateral line canals of the head and the trunk of various fish species. It has been described only in freshwater species although there are reports that it also affects marine fish. Here, we describe the disease in cultured sharpsnout sea bream using histology and scanning electron microscopy and identify several marine species as CUD sensitive. The results of this study correlate the development of the disease with the use of borehole water, indicating that the aetiology is probably associated with water quality rather than nutritional imbalance or infectious agents.

In Europe, fish aquaculture in a marine environment developed following two successive waves: Atlantic salmon and then sea-bass and sea-bream. Rearing "new marine fish species" is sustained for many complementary reasons. This paper aims at presenting the aquaculture status of these "new species," research carried out and then problems and perspectives suggested by farming development in these species.

A phylogeographic analysis based on 6 polymorphic microsatellites was performed on 15 sea bass samples. five from Western Mediterranean, seven from Eastern Mediterranean and three coming from French aquaculture stocks. Among the eastern samples, three did not cluster according to their geographic origin but rather with the occidental group. Furthermore. a somewhat lower allelic diversity was observed within these particular samples, indicating that they originated from a limited number of progenitors of foreign origin. Among the aquaculture stocks, only one revealed a significant reduction of genetic variability, indicating that these stocks are largely outbred and open to wild fishes. The fact that the use of occidental fingerlings to seed broodstocks in the eastern basin facilities dates back to the early 80s at the latest poses the question of the biological mechanisms explaining the maintainance of fish from occidental origin within an oriental context for two or three generations., Une analyse phylogéographique de quinze échantillons de Dicentrarchus labrax dont cinq sont originaires de Méditerranée occidentale, sept de Méditerranée orientale et trois échantillons d'élevage en provenance de trois piscicultures françaises a été effectuée à partir du polymorphisme de six locus microsatellites. Parmi les échantillons orientaux, trois ne se regroupent pas en fonction de leur origine géographique, mais plutôt avec le groupe occidental. Ces échantillons présentent également une diversité allélique légèrement réduite, indiquant qu'ils proviennent d'un nombre limité de géniteurs d'origine occidentale. Parmi les stocks d'élevage, un seul montre une réduction significative de la variabilité génétique, ce qui indique que ces cheptels sont ouverts et font largement appel à des géniteurs sauvages. L'utilisation d'alevins d'origine occidentale pour ensemencer les premières fermes d'élevage du bassin oriental remonte au plus tard au début des années 80. Ceci soulève la question des mécanismes biologiques expliquant le maintien de poissons d'origine occidentale dans un contexte oriental pendant au moins deux ou trois générations.