Penaeid Prawns in Fanga uta Lagoon, Tongatapu

Abstract

The penaeid prawns Penaeus semisulcatus and Metapenaeus ensis were surveyed in Fanga'uta Lagoon, Tongatapu, between July 1975 and August 1976. Catch rates indicate maximum abundance of P. semisulcatus from September to November and minimum abundance between January and February. Juveniles were found in March. Maximum abundance of M. ensis occurred from mid-October to January and minimum abundance from mid-February to mid-April. Spawning occurred outside the lagoon between January and March, and juveniles were found in the lagoon in late April. All areas of the lagoon show a similar pattern of catch rates. Catch rates of prawns were reduced by one-third during the light phase of the moon, and the full moon appears to be a factor associated with moulting in M. ensis.