Multiple paternity in Norway lobster (Nephrops norvegicus L.) assessed with microsatellite markers.

We investigated genetic diversity and the mating system of the Norway lobster (Nephrops norvegicus) in a wild population off the Portuguese coast. Approximately 100 individuals were screened for 2 microsatellite loci. For 11 ovigerous lobsters both the female and a sample of her offspring (24 eggs) were genotyped. High genetic diversity was observed for the 2 markers in the population. Paternity within broods was analyzed by comparing multilocus genotypes of each egg with the corresponding mother, and the male parent contribution was then deduced. Multiple paternity was observed in 6 of the 11 broods studied. In those cases, 2 to 3 male parents were likely to have contributed to the fertilization of the eggs. When multiple paternity was involved, the comparative reproductive success of the male parents was quite even. This is the first report of multiple paternity in the Norway lobster. Comparisons with other taxa are presented, and consequences of multiple paternity are discussed.