Juvenile Penaeid Shrimp Density, Spatial Distribution and Size Composition in four adjacent habitats within a Mangrove-Fringed Bay on Inhaca Island, Mozambique

Abstract—The effects of habitat characteristics (mangrove creek, sandflat, mudflat and seagrass meadow) water salinity, temperature, and depth on the density, spatial distribution and size distribution of juveniles of five commercially important penaied shrimp species (Metapenaus monoceros, M. stebbingi, Fenneropenaeus indicus, Penaeus japonicus and P. semisulcatus) were investigated during a high shrimp recruitment peak lasting from January to June 2002, in four contiguous habitats within a non-estuarine mangrove bay at Saco da Inhaca, Inhaca Island, Southern Mozambique. A total of 14,976 specimens representing the five species were collected by means of a 1m beam-trawl fitted with a 2 mm mesh net with a cod-end. Every two weeks corresponding with spring tides on three consecutive nights, three trawls of 50 meters each were carried out each night in each habitat at 1.40–2.15 a.m. after the daily spring tide high water peak. Species distributions among the four habitats during the six months sampled showed significant differences in habitat preference (p>0.001). Fenneropenaeus indicus, M. stebbingi and P. japonicus dominated the catches in sand flats with densities of 27 ± 0.94, 18 ± 0.98 and 7 ± 0.76 shrimp /50 m2, respectively. Metapenaeus monoceros dominated catches in mudflats at a density of 21 ± 0.78 /50 m2 followed by M. stebbingi with 13±1.2 /50 m2. Penaeu