Notes on the Tasmanian marine crayfish Jasus lalandii Milne Edwards

Abstract

The common marine crayfish, Jasus lalandii (Milne Edwards), which is taken in large numbers off the coast of Tasmania, occurs also in the waters round New Zealand, South Africa, .Juan Fernandez and Tristan da Cunha. Although the crayfish is of considerable importance to the sea fisheries of this State, reliable data concerning its habits and mode of life under local conditions are not available. In South Africa, however�, various phases of the life of the crayfish have been studied and valuable information gained. With the object of obtaining data concerning the biology of the crayfish inTasmanian waters, an investigation was carried out in the Biology Department of the University of Tasmania during the five years 1937-Hl42. Owing to the difficulties of collecting crayfish at a number of separate localities round the coast, it was decided to confine the investigation mainly to crayfish from one locality, namely, Wedge Bay, on Tasman Peninsula. The crayfish were caught in ' crayfish pots ' similar to those used by local fishermen. Fishing was carried out at approximately fortnightly intervals. Six ' pots ' were employed at the one time. On each occasion they were baited and putdown for a period of three hours. The total catch was then forwarded to the University, together with a record of the temperature of the water, the depth, and the distance from the shore at which the fishing was carried out. During the five-year period 1058 specimens of Jasus lalandii and two specimens of Jasus verreauxi (Milne Edwards) were caught and examined. The following notes refer to Jasus lalandii.