Naganandhini, V.; Muthupandi, K.; Vasanth, K.; Neethiselvan, N.; Padmavathy, P., and Radhakrishnan, K., 2023. Influence of hook number on species composition, catch rate, and size of needlefishes in the Gulf of Mannar, India. Journal of Coastal Research, 39(3), 502–508. Charlotte (North Carolina), ISSN 0749-0208.

The contribution of needlefishes from the Gulf of Mannar coast has been remarkable and is presently exploited by pelagic longlines. The J hook is extensively used in longline fishing in the Indian region to capture carnivore fishes, including needlefish. Catch rate significantly differed between the hook numbers. In this context, three hook numbers of 10 J, 11 J, and 12 J were studied from January to May 2022. Results showed that the Ablennes hians was the dominant fish caught (47.9%), followed by Tylosurus crocodiles (22.2%), T. choram (16.6%), and Strongylura strongylura (13.3%); weight-based catches of T. crocodiles (39.7%) were dominantly higher, followed by A. hians (35.9%), T. choram (13.8%), and S. strongylura (10.6%). The two-way ANOVA results revealed that a significant (p <0.05) difference occurred between the hook number and the number of species caught. The largest number of fish were caught with hook number 12 (3769), followed by hook number 11 (2745) and hook number 10 (1445). However, the highest weight of 2749.74 kg was recorded with hook number 11 and the lowest of 1602.65 kg in hook number 10 (p <0.05). This is related to fewer fish caught with hook number 10 and heavy fishing pressure on subadults (<50 cm) due to the use of hook number 12. Considering the maximum total length and weight, the optimum hook number for the commercial exploitation of needlefishes was hook number 11. The catch per unit effort disproportionately increased with the increasing of the hook number; the significant higher contribution of 48.25 individuals/1000 hooks was from hook number 12, whereas hook numbers 11 and 10 were 35.13 individuals/1000 hooks and 18.51 individuals/1000 hooks, respectively.