Seasonal abundance and composition of finfish and shellfish seeds in mangroves of Gangolli estuary, off south-west coast of India

Abstract

The composition and seasonal abundance of the fin and shellfish seeds in mangrove areas of Gangoli estuary were studied for one year from January to December, 2013. Monthly day time sampling was conducted with a rectangular dragnet of 75 m2 length having 5 mm mesh size. The mean monthly density was highest in January (Avg. of 12,996/haul) and lowest during May (Avg. of 859/haul). Thirty species of fish, four species of shrimps and two species of crabs belonging to 26 families were recorded during the study. Ambasis sp., Feneropenaeus indicus, Etroplus suratensis,Leognathus sp., Liza sp., Stolephorus vaganensis, Hemiramphus sp., Terapon sp. and Gerres sp. were the most abundant species/taxa. A total of 10 commercially important species comprising F. indicus, Etroplus suratensis, Liza sp., Gerres sp.,Siganus sp., Lutjanus russei, Macrobrachium rosenbergii, Lutjanus argentimaculatus, Sillago sp. and Penaeus monodon constituted 8.5% (April, 2013) to 93.7% (October, 2013) with an average of 37.2% of the total fish and shellfish seeds. Higher Species diversity (H') and Species richness (D) was recorded during January. The result of the present investigation gives an insight of the abundance and seasonality of commercially important fish and shellfish seeds, which may facilitate the brackishwater fish farmers to exploit the seeds more pragmatically for their culture practice.