Diel and lunar variations in larval supply to Malindi Marine Park, Kenya

Abstract

Understanding larval ecology and the mechanisms used in dispersal and habitat selection helps to better understand the population dynamics of coral reef communities. However, few studies have examined patterns of larval supply to reefs sites especially in the WIO region. Temporal patterns of fish larval occurrence in Malindi Marine Park, Kenya, were studied to assess diel and lunar patterns of larval replenishment. Monthly and 24-hour sampling for fish larvae were carried out between March 2005 and March 2007.Replicate samples were obtained by towing a2- meter long plankton net (500µm mesh size, 0.2 m² mouth area) for 6 minutes within the park. Larval abundance (larvae.100 m^-3_± SE) in the park was higher during spring tides (951± 408) than neap tides (394 ± 260). Nocturnal larval abundance was 13 fold greater than day-time concentrations independent of tidal regime.The dominant families in the larval pool were Engraulidae, Labridae, Blenniidae and Gobiidae. A spectral time-series analysis showed larval supply occurred after a 30 day cyclical pattern associated with the new moon phase and northeast monsoon season.