676 Environment & Ecology 31 (2A) : 676—678, April—June 2013 Website: environmentandecology.com ISSN 0970-0420 Length-Weight Relationship of Rastrelliger kanagurta (Cuvier) from Mangalore Region Shrinivas H. Hulkoti, S. M. Shivaprakash, H. N. Anjanayappa, S. R. Somashekara, S. Benakappa, A. S. Kumar Naik, L. Ganesh Prasad, Jitendra Kumar Received 30 December 2012; Accepted 24 January 2013; Published online 30 January 2013 Abstract The length-weightr relationship of Rastrelliger kanagurta (Cuvier) was estimated and given by the equations, male W = 0.0052 L 3.1737 and female W = 0.0039 L 3.2686 . The b value did not show significant difference between sexes. Hence, the pooled equation for male and female obtained at W = 0.0045 L 3.2234 . The fluctuation in the relative condi- tion factor (K n ) values with respect to size indicated that condition of fish showed that an increase trend in size of fish. The K n value steadily increased up to 21 cm and thereafter decreased and again showed that increasing trend. The seasonal fluctuation in the relative factor of the both the sexes was attributed to the sexual cycle and food intake. Keywords Rastrelliger kanagurta, Length-weight relationship. Introduction The length-weight relationship (LWR) of fishes are important in fishery biology because they allow the S. H. Hulkoti, S. M. Shivaprakash, H. N. Ajanayappa*, S. R. Somashekara, S. Benakappa, A. S. Kumar Naik, L. Ganesh Prasad, Jitendra Kumar Department of Fisheries Resources and Management College of Fisheries, Mangalore—575002. e mail : anjanayappahn@rediffmail.com * Correspondence estimation of the average weight of fish of a given length group by establishing a mathematical relation between the two (1). They are also useful forassessing the relative well being of the fish population. Like any other morphometric characters, the length-weight re- lationship can be used as a character for the differntiation of taxonomic units and this relationship is seen to change wit various developmental events in life such as metamorphosis, growth and onset of maturity. Besides this, the length-weight relationship can also be used in setting yield equation for estimat- ing the number of fish landed and comparing the population in space and time (2). The empirical rela- tionship between the length and weight of the fish thus enhances the knowledge of the natural history of the fish. Materials and Methods The present study on Rastrelliger kanagurta from Mangalore is based on a randon samples of 1124 in- dividuals were fortnightly collected from fish landing centre and fish market as well, individuals were rang- ing in size from 11 to 26 cm total length (TL) of which 590 were male and 534 were female. The parabolic equation W = aL b (Le Cren, 1951) was linearized to the form Y = A+BX where, Y = log W, A = log a, B = b and X = log L. Based on this equation, constants A and B were estimated for each month using least squarres method. The data for the sexes were treated sepa- rately in order to examine differences between sexes. Analysis of co-variance (3) was used to test the sig-