Diel variability of size and catch rate of three fish species and three penaeid prawns in the NW Red Sea trawl fishery

Catch rates and sizes of Saurida undosquamis and Nemipterus japonicus were more variable during daytime. But, Pomadasys stridens were more variable in night tows. Catch rates of S. undosquamis and N. japonicus were higher during daytime and of significantly small mean fish size. Inversely, P. stridens had significant higher catch rates and the fish caught were smaller in night tows. Variability of catch rate and size of Penaeus semisulcatus and Penaeus japonicus was higher at night. Daytime catch rates were significantly lower and of smaller mean shrimp size. Penaeus latisulcatus was available only at night.