Attempt at biochemical characterization of sand smelt Atherina boyeri Risso, 1810 (Pisces, Atherinidae) populations from the Camargue (Rhone delta, France)

A high degree of polymorphism has been evidenced in Atherina boyeri. Severa l local populations have been distinguished in various studies, on the basi s of morphological, morphometric, and biochemical parameters. The Rhone del ta (the Camargue) exhibits a wide range of coastal brackish lagoons and fre shwater marshes differing in their isolation, salinity, and distance from t he sea. Some A. boyeri populations of these water bodies can migrate, parti cularly to spawn and may differ in their degree of differentiation and with regard to marine ones. We used electrophoresis to analyze small polymorphi c muscle proteins, the parvalbumins (PA), whose isoform distribution is typ ical of a species and even of a population. We found a quite homogeneous 'l agoon' type distribution (presence of PA IV and III, lack of PA V typical o f marine specimens) in populations from the Camargue. Three subgroups were distinguished in each population according to the percentage of PA IV/PA II I. Two neighboring populations more connected to the sea were characterized by a greater preponderance of the PA IV isoform. (C) 1999 Elsevier Science Ltd. All rights reserved.