Fecundity and egg loss during incubation in Norway lobster (<i>Nephrops norvegicus</i>) in the North Tyrrhenian Sea

Abstract

Fecundity of Norway lobster females of the northern Tyrrhenian Sea was studied in order to examine the time and the size of the eggs during their development incubation, as well as egg loss. Females incubate their eggs under the abdomen for a period of about six months. Mean diameter of hatching eggs is 1.63 mm. The egg loss estimated from the oocytes to the egg at about one month before hatching averaged 49.5%, whereas from the oocytes to close to hatching averaged 71.5%. A mean rate per month of egg loss of about 10% through the incubation period was estimated for Nephrops norvegicus from the northern Tyrrhenian Sea. The counts obtained from eggs that are close to hatching give more reliable estimates of a female's potential contribution of larvae to the population.