Length–weight Relationships of Six Rare Deep‐sea Fishes From the Andaman and Nicobar Archipelago, India

Abstract

This study presents the length-weight relationships (LWRs) for six deep-sea fish species from the deep-waters of Andaman and Nicobar archipelago of India (70 29’130’’N − 120 44’ 480’’N and 920 19’ 580’’E − 930 24’ 440’’E). We employed bottom trawl using High Speed Demersal Trawl (HSDT-II CV, mesh size of 30 mm in the cod end) between March-April 2017, off the Indian coast between 295 and 650m depth. The speed of the vessel kept as average 3.5 knots, with ~ 1-hour duration. The specimens were collected from each haul, the samples sorted in to species level, and then we have taken few species for LWR study, in which previous reports are not available. We estimated the values for the parameter b of the length-weight relationship together with Coefficient of determination scores using ordinary least squares regression method. LWRs were significant with r2 values ranged from 0.94 to 0.96 and ‘b’ values are 2.55 for Apristurus indicus, 2.97 for Benthobatis moresbyi, 2.55 for Epigonus elongates, 3.43 for Gavialiceps taeniola, 2.96 for Polymixia fusca and 2.92 for Ostracoberyx dorygenys. In addition, a t-test was applied to test b value to verify the significant difference from the isometric value (b = 3). We also compared the current estimate with the Bayesian length-weight in the Fishbase. The parameters have a wide application such as biology, ecology, species management and stock assessment. However, the current estimate of the LWR restricted to the given length range and geographical region. Therefore, we recommend more studies to confirm the growth pattern of these fishes. Moreover, this study provides significant inputs to the knowledge on the least explored deep-water fishes of Andaman and Nicobar Archipelago of India.