The distribution and abundance of planktonic penaeid larvae in Tudor creek, Mombasa, Kenya

Abstract

The temporal distribution and abundance of penaeid prawn larvae in surface waters of Tudor creek were studied. Only late mysis and early post mysis stages of development were encountered in the creek waters with a descending gradient from the mouth station (station 1) to the innermost station 5. Larval encounter incidence (% incidence) was highest in plankton tows taken during night spring tides (59%) followed by night neap tides (45.4%), day spring tides (34.9%) and day neap tides (21.4%). This encounter incidence was more skewed towards the seaward stations (1 and 2) during the neap tides than during spring tides. Likewise, larval density (mean catch/standard 5 min. tow) decreased less steeply up the creek during spring tides than it did during neap tides. Higher catch rates were in general obtained in night samples than in day samples at each station and in each neap/spring phase. The diel cycle had a greater effect on both incidence and abundance of larvae than did the tidal cycle. Intensified larval incursion into the creek was observed between March and June.