Biometric relationships of the Indian abalone Haliotis varia Linnaeus 1758 from Mandapam waters of Gulf of Mannar, south-east coast of India

Abstract

Biometric relationships,including length-weight relationship, in different size groups of the Indian abalone Haliotis varia collected from the ‘paars’ off Mandapam coastal waters of the Gulf of Mannar were studied. In H. varia, length-weight (L-W) relationship between males and females in the same size group was not significantly different and therefore a combined equation was derived. The L-W relationship had reasonably good fit in medium sized abalones (shell length (SL) 25-35 mm, r2 = 0.8368), while it was poor in small sized abalones (SL 15-25 mm, r2 = 0.2609) and lowest in large sized abalones (SL 35 - 45 mm, r2 = 0.1641). The L-W relationship in different size groups indicates that the growth in length and weight was initially allometric and subsequently became isometric in medium sized abalones and finally reverted back to allometry. In all other biometric relationships such as shell length - shell width (SL-SW), shell length - shell height (SL-SH) and shell width - shell height (SW-SH), allometric growth was observed in all the size groups. The results of the study may form the baseline information on the abalone population in Indian waters to facilitate their commercial exploitation.