SEASONAL VARIATION IN MORPHOMETRIC CHARACTERISTICS OF SELECTED FISHES OF CHENNAI COAST IN RELATION TO HYDROGRAPHIC PARAMETERSHEMASANKARI PALANI, VASANTH KRIPA, D. PREMA, P. KALADHARAN, K. VIJAYAKUMARAN, R. NARAYANA KUMAR AND A. MARGARET MUTHU RATHINAMAbstract Morphometric characteristics are studied in order to identify the species easily. Morphometric characteristics refer to the measurement of length of different parts of the body of fishes. These lengths of different parts vary from species to species and this paper describes the morphometric characteristics of the Rastrelliger kanagurta, Mackerel and Sardinella longicepsis Oil sardine fishes. The morphometric characteristics include 21 different measurements and 5 derived parameters. The fresh fish after harvest from sea were collected from Kasimedu fish landing centre and brought to the lab, washed thoroughly on the outer surface and then kept on the graph sheet to mark the different points of the fish so that the distance between each part is calculated. The study was conducted in Kasimedu fish landing centre of Chennai. The Kasimedu lattitude and longitude were 13°117âN and 80°293âE. The morphometric characteristics of Oil sardine and Mackerel for 4 different seasons, post monsoon, summer, pre-monsoon and monsoon season for the consecutive 4 years, viz. 2008, 2009, 2010 & 2011 were studied. The morphometric characteristics were correlated with the hydrographic parameters of temperature, salinity, pH, dissolved oxygen, total soluble solids, chlorophyll a, b & c, primary productivity, gross and net and nutrients, nitrate, phosphate and ammonia. The results showed that in the year 2011, temperature shows positive correlation with head length, r=0.02 and with total length, r=0.49 for Mackerel. In Oil sardine, temperature is correlated with total length, r=0.12 and with head length, r=0.04). The correlation of other body parts with that of the hydrographic variables were also made for all 4 years and their seasonal effect were also studied. The total length in the year 2011 is more, 183.47mm among the 4 years tested and among the seasons, the length in the summer season is more in Oil sardine. In Mackerel, in the year 2009 the total length is more, 256.09 mm and among the seasons tested, in post monsoon season. The length of the head is more in summer season in Oil sardine in almost all the 4 years tested and in Mackerel the length of the head is more in summer season in 2008 and 2009 and in post monsoon season in 2010 and 2011 the length of the head is more. The values of different lengths of both Mackerel and Oil sardine are significantly different from each other at 5% level of significance. |