La domestication du barbeau fluviatile, Barbus barbus (L.) (Cyprinidae) en vue de la production massive contrôlée d'alevins pour le repeuplement des rivières. Résultats et problèmes.

The barbel populations are decreasing in number in the Belgian river Meuse and most of its tributaries. In 1982 our laboratory undertook a programme of mass rearing of fry and fingerlings for experimental restocking purposes. In May 1982, wild barbels were electrofished on the spawning grounds in the River Ourthe; the ova were stripped from the females in the field and artificially inseminated with sperm. The fertilized eggs were transferred into a hatchery for incubation, and subsequently, the alevins were reared in tanks supplied with a heated effluent (20-24°C) from the Tihange nuclear Power Plant. Under these conditions, the young barbels exhibited an accelerated growth, and both males and females attained their sexual sexual maturity in captivity as early as January 1984. These barbel were used for artificial reproduction and production of of 100 percent domesticated fish (around 200.000 fry produced in 1984 and 1985). From October 1983 to December 1985, 49 000 barbels with a size of 4-18 cm were released into various rivers where the species was highly threatened or had become extinct, as, for example, in the Mehaigne stream, a small (maximum width : 10 m) tributary of the river Meuse in Huy. The first restocking experiments carried out in the Mehaigne indicate that the cultured barbels survive well and grow at a normal rate after release in the wild. But before generalizing that management practice, it is necessary to study the following problems : i) what is the ecological, physiological and genetic quality of the cultured barbels; ii) what are the population dynamics of the stocked barbels and their interaction with the wild populations. The barbel is a new species for intensive culture for restocking purposes in Europe, and that offer a real opportunity to enter into a demo-genetiic research programme involving European laboratories.