Summary of Abstract Submission

Abstract Submission No. IO50-04-0051PresentationPoster

SPATIAL AND TEMPORAL VARIATIONS OF INFAUNAL MACROBENTHIC COMMUNITIES ALONG THE COASTAL WATERS OF OFF-KOCHI

Naidu, SA*1, Kumara Swami, M1, Rao, GD1, Siva Sankar, R1, Vishnuvardhan, K1, Rao, VD1

1 ICMAM Project Directorate, Ministry of Earth Sciences, India

ABSTRACT :

The present study is an attempt to understand the spatial and temporal variability of macrobenthic community structure in the coastal waters of off-Kochi. Higher macrobenthos density was found during monsoon followed by spring inter monsoon and winter monsoon. Irrespective of the seasons the density of organisms was lower at shallower depths (10 and 20m) when compared to that of deeper depths (30, 40 and 50m). The lower benthic abundance and biomass in shallow depths indicates the reduced depository environment due to the high currents and trawling activities in the coastal waters of off-Kochi. The macrobenthic population was dominated by polychaetes, followed by crustaceans, molluscans and others. Heterogeneous substratum such as silty sand and clay sand which was found at deeper depths was found to have higher diversity, richness and number of species when compared to that of homogeneous substratum such as silty sand and clay sand found in the shallow depths. During the monsoon season the dissolved oxygen in the water column was below 5ÁM which was 50 times lower than that observed in the other seasons. However, no stressed morphological behaviour like expansion of gills in polychates was noticed. This might be due to the intensified physical mixing processes allowing reoxygenation of water column along the coastal waters of off-Kochi.