Journal of Biological Sciences1727-30481812-5719Asian Network for Scientific Information10.3923/jbs.2009.357.361Sepioteuthis lessoniana Lesson 1830 (Cephalopoda:Teuthida) from the Jaffna Lagoon, Sri Lanka]]>SivashanthiniK. CharlesG.A. ThulasithaW.S. 4200994In the present study, length-weight regression equations were derived for male and female S. lessoniana collected from the Jaffna lagoon, Sri Lanka in order to find out the regression parameters and growth pattern of this species. Sepioteuthis lessoniana (Lesson 1830) are one of the commercially important group of cuttlefishes and becoming an important model system for neurobiological and behavioral research. It appears to be the most adaptable species to the laboratory environment and there exist a need for detail study on length-weight relationship for this species. Such a mathematical equation enables conversion of one parameter in to another as is often required during monitoring field measurements. Regression coefficients were estimated by using the logarithms of the mantle lengths and the corresponding weights and the growth pattern of the species was also noticed. The curvilinear relationships of mantle length-weight relationships for male and female were TW = 0.200*ML^{2.477} and TW = 0.229*ML^{2.437}, respectively. Covariance analysis for mantle length-weight relationships of males and females revealed that there is no significant difference (p>0.05) between male and female and hence a common formulae of TW = 0.213* TL^{2.459} was derived for S. lessoniana. The ‘b’ values 2.477 and 2.4347 obtained for male and female, respectively indicate that the growth rate significantly differ from the ideal value ‘3’ and its growth said to be negative allometry.]]>Bagenal, T.B. and F.W. Tesch,1978Chojnacki, J.,1973Illex illecebrosus Lesueur and Loligo paelei (Lesueur).]]>De Bruin, G.H.P., B.C. Russell and A. Bogusch,1994Flamigni, C. and O. Giovanardi,1984Loligo vulgaris Lam.]]>Froese, R.,2006Gonzalez, A.F., G.C. Bernardino and A. Guerra,1992Illex coindetii in Galician waters (NW Spain) based on statolith analysis.]]>Hanlon, R.T., P.E. Turk and P.G. Lee,1991Hile, R.,1936Leucichthys ardeti (Le Sueur), in the lakes of the North-Eastern Highlands.]]>Ikeda, Y., I. Sakurazawa, Y. Sakurai and G. Matsumoto,2003Jayaprakash, A., 2001Cynoglossus macrostomus Norman and C. arel (Schneider).]]>Karnik, N. and K. Chakraborty,2001Loligo duvauceli (d'Orbigny) (Mollusca: Cephalopoda) off Mumbai (Bombay) waters, West Coast of India.]]>Krstulović Šifner, S.,2000Loligo vulgaris (Lamarck, 1798) u Jadranu.]]>Manfrin Piccinetti, G. and O. Giovanardi,1984Sepia officinalis L. dans l'Adriatique obtenues lors de expeditions pipeta.]]>Marano, G.,1993Martin, W.R.,1949Mhitu, H., Y. Mgaya and M. Ngoile,2001Petrakis, G. and K.I. Stergiou,1995Ragonese, S. and P. Jereb,1992Illex coindetii Veranv, 1839 (Mollusca: Cephalopoda) in the Sicilian Channel.]]>Ricker, W.E.,1975Varoopa, P. and K. Sivashanthini,2006Mollusca) from the Jaffna Lagoon, Sri Lanka.]]>Snedecor, G.W., 1963Somasekaram, T.,1997Somasundarampillai, A.,2002Zar, J.H.,1996