Movements and growth of tagged Blue Endeavour Prawns, Metapenaeus endeavouri (Schmitt 1926), in the Western Gulf of Carpentaria, Australia

Abstract

Mark-recapture experiments, conducted near Groote Eylandt in the western Gulf of Carpentaria during 1984, were used to examine movements and growth of blue endeavour prawns, Metapenaeus endeavouri.

The mean distance moved by tagged animals was only 12.7 (s.e.±1.0) km, but a few were recaptured > 100 km from their release sites. The mean time at liberty was 36.8 (±1.6) days, the maximum being 155 days. The distance and speed of movements were not related to the size or sex of tagged prawns. Nonuniform recapture patterns corresponded largely with fishing effort. Recaptures per unit effort (R/f analyses), used to account for nonuniform fishing effort, indicated that there was no directionality in movements. Thus, tagged specimens of M. endeavouri dispersed slowly across suitable adult habitat, with limited intermixing of adults from stocks around Groote Eylandt.

Estimates of the von Bertalanffy growth parameters L_∞ and K for each sex were obtained for data from summer and winter releases. The fit of the von Bertalanffy model to summer data was limited by the small number of recaptures. The fit of the model to winter data was improved by removing early recaptures, and these estimates are presented as the primary descriptors of growth in M. endeavouri. Parameter estimates did not differ significantly between seasons, but L_∞ differed between sexes and K differed between sexes in winter. Predicted growth corresponded to the progression of modes in length-frequency data from commercial catches.