Length-Weight Relationships and Condition Factor of 15 Coastal Fish Species (Family: Lethrinidae) of the Gulf of Mannar, Southeast Coast of India

The length-weight relationships (LWRs) of 15 lethrinid fish species of the Gulf of Mannar, Southeast Coast of India were studied. The fish specimens were collected fortnightly from three main fishing harbours Thoothukudi, Pamban and Chinnamuttom from December 2022 to November 2023. These coastal fish species were caught usinggears such astrawl net, gill net, hook and line.In addition, three different condition factors werealso determined for these species. Thecalculatedgrowth coefficient, i.e., the b value (shape parameter) of all these species fell within the expected range of2.5 to 3.2. Further, a new maximum length was recorded for two species viz., Lethrinus microdon (82.0 cm) and Lethrinus lentjan (53.0 cm).The calculated minimum and maximum Fulton condition factor ( K F ), Relative condition factor ( K R ), and Allometric condition factor ( K A ) varied from 1.0169 to 1.7557, 0.5023 to 1.1050 and 0.0088 to 0.0757, respectively. For the first time, the study provides insights on LWR estimates for two species of pig-face bream viz., Lethrinus conchyliatus and Gymnocranius elongatus in Indian waters. This information will be valuable for constructing the frontline data for future biological studies in the Gulf of Mannar region.