ABSTRACT The paper presents the length-weight relationship (LWR) parameters of Lates calcarifer reared in open sea floating cages off Karwar along the south-west coast of India. The relationship obtained in the present study was W = 0.000008299L 3.088 which indicates that seabass reared in open sea floating cages in semi-intensive condition does not differ significantly in body appearance from their counterparts found in natural conditions. The growth of the fishes was found to be positively allometric. Keywords: Allometry, Growth, Lates calcarifer, Length-weight relationship, Open sea floating cage, Semi-intensive Length and weight data based statistics are the cornerstones in the foundation of fishery research and management. The relationship between total length (L) and total weight (W) for nearly all species of fish is expressed by the equation: W = aL b . The exact relationship between length and weight differs among species of fish according to their inherited body shape and, within a species according to the robustness of individual fish. The relationship between the length and weight of a fish is used by fisheries researchers and managers for two main purposes (Le Cren, 1951). First, the relationship is used to predict the weight from the length of a fish. This is particularly useful for computing the biomass of a sample population of fish from the length-frequency of that sample. Second purpose is usually generically referred to as describing the condition of the species. The Central Marine Fishereis Research Insitute (CMFRI) is instrumental in the successful development of open sea floating cage culture for various finfish and shellfish species along the east and west coasts of India. The Asian seabass Lates calcarifer, is one among the promising candidate species for mariculture ventures in India, because of its fast growth rate, tolerance to wide environmental conditions and its sustained demand in both domestic and export markets. Open sea cage culture has been expanding in recent years on a global basis and it is viewed by many stakeholders in the industry as "the aquaculture system of the millennium". Cage culture has made possible, the large-scale production of commercial finfish in many parts of the world and can be considered as Indian J. Fish., 60(1) : 139-140, 2013 Note the most efficient and economical way of rearing high valued fish. In the present study, length-weight relationship was estimated for L. calcarifer cultured in open sea floating cages in the coastal waters of the Arabian Sea off Karwar along the south-west coast of India. Hatchery produced seabass seeds, by induced spawning, were used for the present study. Uniform sized fingerlings were stocked in circular open sea cages of 6 m diameter. The stocking density used for growout culture in open sea cages were 2000 nos. per cage. The growth data were collected during monthly samplings, between December 2009 and July 2010. Water samples were collected from the open sea cage culture site during the morning hours at daily intervals to monitor parameters such as temperature, pH, dissolved oxygen, salinity and ammonia The fishes were fed with fresh chopped oilsardine @10% of the total biomass initially for a month and later @2% of the total biomass. A total of 450 fishes were randomly collected for measurements during different periods of the experiment. Total length (TL) and body weight (W) of the sampled fishes were measured to the nearest 1 mm and 0.01 g, respectively. The length-weight relationships were derived from the formula, W = a L b , where W is total body weight (g), L the total length (mm), a and b are the coefficients of the functional regression between W and
