Influence of lunar phases on fish landings by gillnetters and trawlers

Abstract

Observations made on new moon, full moon and during both quarters revealed variations in total catch as well as individual species catch in gillnetters and trawlers. Gillnet catches of sardines and mackerels showed a gradual increasing trend from new moon to full moon and then a decline towards the new moon whereas, barracuda and tuna catches exhibited an increasing trend from full moon to new moon. The catches of seerfish and sailfish were high during full moon to new moon quarter and were nominal during full moon. In trawl catches, during the first half of new moon and full moon days, Fenneropenaeus indicus and Penaeus semisulcatus were caught in large numbers and Fenneropenaeus merguiensis dominated the later half. Metapenaeus monoceros and Penaeus monodon were caught in lesser quantities. Maximum catch per unit effort (CPUE) for gillnetting and trawling were recorded during new moon (52.35 and 9.97 kg h-1) and minimum values during full moon quarter (2.5 and 1.63 kg h-1). Larger size groups were dominant during new moon for all species and the differences were significant (p<0.01). Significant variations in total catch during different lunar phases were noticed for fishes caught by gillnetting as well as the shrimps caught by trawling.