ANALYSIS OF LENGTH – WEIGHT RELATIONSHIP OF Nibea maculata (SCHNEIDER, 1801) FROM THOOTHUKUDI COAST

A study was undertaken to find out the relationship between the length and weight of Nibea maculata (Schneider, 1801) in Thoothukudi coast for the period of one year from July 2006 to June 2007. During the study, the size range of specimens various from 10 cm to 25.8 cm. The calculated 'b' value of N. maculata was analyzed against '3' using student's t - test which indicates the isometric growth.

The Sciaenidae group fishes are one of the commercially important species along the trawlers of Thoothukudi coast. The estimated sciaenid fish production of Thoothukudi was 830 tonnes which contributes about 0.27% of the total marine fish landing of the Tamilnadu (Anon, 2006). Among the sciaenids, blotched croaker, N. maculata is the major fishery in this region. Though the length - weight relationship of several sciaenid fishes from Indian waters were undertaken. (Jayasankar, 1989 and 1990; Manojkumar and Acharya, 1990 and Chakraborty, 1992). The information on the length-weight aspects of N. maculata in Thoothukudi region is not available. Hence the present study has carried out.

Samples of N. maculata were collected from the trawlers operating in the Thoothukudi fishing Harbour. Total length in centimeter (snout to edge of the caudal fin) and weight (nearest to 0.1g) were recorded for N. maculata the study is based on 250 specimens of the different length group ranges from 10.0cm to 25.8cm.

The length weight relationship was calculated using the following formula.

Log w           =      log a + b log l

Where,

W- Weight in gram, L- Total length in cm, a & b - Constants.      

In order to verify if calculated 'b' value was significantly different from 3, the student's t- test was employed.