Reproductive dynamics of the male Norway lobster, Nephrops norvegicus (L.)
The aim of this research was to examine various aspects of the reproductive biology of male Nephrops norvegicus. Due to differnces in the reproductive behaviour between the sexes males suffer greater fishing mortality. A reduction in the numbers and size of males within a fished population may have effects on the reproductive output of the population. The structure and functioning of the testes of N. norvegicus were examined histologically. The testis appeared to be made up of many acini, which drain into convoluted collecting tubules that carry the developing spermatozoa to the vas deferens. Each acinus appears to have an independent cycle of production by which secondary spermatophores are produced. There is a pronounced seasonal development of the ovaries in female N. norvegicus, however, no such seasonality has been observed in the testes. This study used histological and biochemical analyses to determine any changes in the level of reproductive output of the testes over the course of the year. There were no observed changes in the structure of the testes. There was no thickening of the tubule walls which has been observed during the breeding season in other decapods. There was no change in the amount of sperm produced over the course of the year.