Fecundity of the deep-water spiny lobster Palinurus delagoae off eastern South Africa

Abstract

The fecundity of a deep-water spiny lobster (Palinurus delagoae) was investigated
using egg-bearing females caught in traps set in two regions of the South African east coast: south of Durban (South) and near Richards Bay (Central). Fisheries observers on a commercial fishing vessel collected 161 females with egg-masses in developmental Stages 1 - 3 during 2004. Egg-masses were removed, oven-dried and the eggs counted. Relationships between fecundity and carapace length (CL) were linear and females caught in the south carried significantly more eggs than those in the central region at equivalent lobster sizes. Egg-loss during incubation was 10 - 16% (for CLs of 75 - 140 mm) between the 1st and 3rd egg stages, and egg diameter increased from 0.96 - 1.04 mm in stage 3. Estimates from the present study compare well with those of two other species in this genus, and confirm that the deep-water Palinurus lobsters produce fewer, but larger eggs than is usual in shallow-water lobster genera. Larger eggs, well-developed larvae and a shorter pelagic drifting phase may have evolved in P. delagoae to counter larval over-dispersal and loss in the Agulhas Current, and to retain populations in the vicinity of the south-east African coast.

Keywords: Palinurus delagoae, fecundity, reproduction, egg-bearing

West Indian Ocean Journal of Marine Science Vol. 4 (2) 2005: pp. 135-144