Movements of tagged tiger prawns, Penaeus spp., in the western Gulf of Carpentaria

Abstract

The pattern of movements of the tiger prawns P. esculentus and P. semisulcatus in the western Gulf of Carpentaria, is described on the basis of three tagging experiments carried out in 1981. During these experiments, 13 180 individuals of P. esculentus and 6812 individuals of P. semisulcatus were tagged with Floy streamer tags and released in waters adjacent to Groote Eylandt. The first of the experiments was conducted in inshore waters north of Groote Eylandt in February. The second and third experiments were conducted in waters farther offshore north and south of Groote Eylandt in May-June. Logbook fishing-effort data were used in the interpretation of movement patterns from the geographic distribution of recaptures. From the February releases north of Groote Eylandt, both species showed movement offshore although, as a result of different directions of movement, the two species exhibited some degree of separation in the offshore fishery. The distribution of P. esculentus recaptures was generally east of the release area whereas that of P. semisulcatus was north-east. The distribution of recaptures from the June releases north of Groote Eylandt showed much less movement and separation of species than for those released inshore in February. Similarly, the recaptures from the May-June releases south of Groote Eylandt showed relatively little movement. With a few notable exceptions;these prawns exhibited only a gradual dispersal from the area of release.