Reproductive processes in the European lobster, Homarus gammarus

The population biology, size at onset of maturity and individual fecundity of the European lobster, Homarus gammarus, have been studied in three fisheries on the English and Welsh coast. Differences were observed between the fisheries and temperature regimes of the three sample areas, and these were reflected by variations in size distributions, catch per unit effort and landings statistics. Current national fisheries management legislation consists solely of a minimum legal landing size legislation of 85 mm carapace length. Estimates of the sizes of both male and female maturity varied considerably between the three study sites. The smallest ovigerous female was 81 mm carapace length at Bridlington, 95 mm carapace length at Dale and 76 mm carapace length at Selsey. The sizes at male maturity showed both spatial and temporal variation, and ranged between 73 mm and 87 mm carapace length. Regional variations in size at onset of maturity have important implications for fisheries management strategy, and may indicate the requirement for local minimum legal landing size legislation. This study confirmed previous work suggesting a linear relationship between clutch size and female carapace length. This relationship exhibits regional and temporal variation, which requires further research for the determination of potential causes. Local temperature effects are suggested to influence the duration of the reproductive cycle of the lobster and therefore individual fecundity. The spawning frequency of the lobster has been suggested to increase with increasing female size, and may show regional variation.