Comparisons of size at maturity and fecundity of two Scottish populations of the European lobster, Homarus gammarus

Sampling of Homarus gammarus on commercial boats and regular visits to local ports were carried out during 1999–2001 for the Firth of Forth and Hebrides fisheries. Biological data on size, sex, morphometric measurements and egg samples were collected. Size at the onset of sexual maturity (SOM), fecundity and egg development were compared between populations. Techniques that require transformed (Logarithm base e) or untransformed morphometric data, were applied to the data. Lobsters from the Firth of Forth had smaller SOM ( = 80 mm carapace length (CL) and = 79 mm CL) than those from the Hebrides ( = 98 and = 110 mm CL). Fecundity (x ̄ = 8154 eggs) for the Firth of Forth was lower than for the Hebrides (x ̄ = 14 238 eggs). ANCOVA showed no significant differences in the size–fecundity relationship between locations (F1,1 = 2.62, P> 0.05) for lobsters with eggs in which the eye spot index (ESI) was between 0.29 and 0.54, using CL and ESI as co-variates. The reliability of the methods and the resulting estimates are discussed