Morphometric relationship and fishery of Indian Ocean lobsterette, Nephropsis stewarti Wood-Mason 1873 along the southwest coast of India

Abstract

The Indian Ocean lobsterette, Nephropsis stewarti, is landed at Mangalore Fisheries Harbour by deep-sea trawlers operating at 250-500 m depth off North Kerala and South Karnataka from the year 2000 onwards. During 2000-2006, the average annual landing of the species was estimated at 23.3 t with the highest landing in 2001 (51 t) and the lowest in 2005 (9 t). Studies on length-frequency and morphometric characteristics of the lobster were carried out during 2005-2006. Fishery was constituted by the length range 58-158 mm. Females < 80 mm (total length) were found to be immature. Highest percentage (33%) of immature females was found during November, 2006. The total length-body weight relationships derived for males and females were W = 0.01737 L2.942954 and W = 0.01873 L2.89537 respectively. The carapace length-body weight relationships were W = 0.66626CL 3.09198 for males and W = 0.62579 CL 2.89828 for females. Significant differences between slopes and elevations of carapace length-body weight and carapace length-total length relationships were found between sexes. Males were found to be heavier than females of similar size