Reproductive success factors of syngnathus abaster risso 1826 pisces teleostei syngnathidae in a mediterranean lagoon environment mauguio lagoon france
Tomasini J A.; Quignard J P.; Capape, C.; Bouchereau J L.
Acta Oecologica 12(3): 331-355
Syngnathus abaster is the only sedentary Syngnathidae occurring in the lagoon of Mauguio. Generally, the breeding season extends from March to October. Some specimen reach their first sexual maturity as soon as they are three-four months old, before the winter following their birth. At the beginning of the next breeding season, almost all the individuals are adult. Females are batch spawners. Males can incubate several broods during one breeding season and clutch size is correlated positively with body size, as is the number of ovocytes of each female's batch. Incubation period in aquarium (temperature: 20-21.degree. C) is about fifteen days, and a new mating occurs eight days the litter. Global sex-ratio appears to be slightly skewed towards females. Females' potential fecundity per breeding act (average: 21-23 ovocytes) is lower than that of males' brood pouch (average: 36-52 eggs). This fact involves rapid maturation of females between two breeding sequences and polygyny. After being maximum in May (females) and June (males), fecundity falls until the end of the breeding season. When females have only few ovocytes to place at males' disposal and, in spite of the polygyny, ovocytes are always distributed among the greater number of operational males and are not concentrated in some priviliged males. This tactic reduces risks of destruction of broods and contributes, with the other facts evoked before, to the reproductive success of the population of S. abaster in the lagoon of Mauguio.