Sledges for daytime sampling of juvenile penaeid shrimp

Daytime catches of juvenile penaeid shrimp from two modified sledges (providing stimulation by water-jet or electric current) were compared with catches from a conventional sledge (or beam trawl) used at night. The results indicate that the daytime use of a water-jet sledge is a suitable alternative when night-time sampling is precluded. Mean catch rate of the Brown tiger prawn (Penaeus esculentus) in the daytime water-jet sledges was not significantly different from the night-time conventional sledges, but catches in the daytime electric trawls were significantly less. In contrast, the catches of the Endeavour shrimp (Metapenaeus endeavouri) and the Greentail shrimp (Metapenaeus bennettae), in both the daytime water-jet and daytime electric sledges, were significantly lower (approximately one-quarter) than in the night-time trawls. There was no significant difference between the length-frequency distributions of P. esculentus, M. endeavouri or M. bennettae caught in the conventional night-time and in the daytime water-jet sledges. © 1992.