Fishery, population characteristics and stock status of the bigeye thresher Alopias superciliosus Lowe, 1841 off Thoothukudi, south-east coast of India

Manojkumar, P P and Ranjith, L and Karuppasamy, K and Kanthan, K P (2021) Fishery, population characteristics and stock status of the bigeye thresher Alopias superciliosus Lowe, 1841 off Thoothukudi, south-east coast of India. Indian Journal of Fisheries, 68 (4). pp. 14-21.

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Abstract

Fishery, population parameters and stock estimates of the bigeye thresher Alopias superciliosus Lowe, 1841 from the Thoothukudi coast of Gulf of Mannar Marine Biosphere Reserve (GoMMBR) was studied during the period 2015 to 2019. Results of the study reveals that the estimated annual average production of sharks from Thoothukudi region was 105 t of which the dominant shark species was A. supercilious (52.70%). The length of the sampled A. supercilious ranged between 108 and 265 cm. Results of the length-weight relationship showed negative allometric growth with b value of 2.66. The growth parameters viz, asymptotic length (L∞), growth co-efficient (K) and arbitrary origin of growth (t0 ) were estimated at 367 cm, 0.39 y-1 and 0.12 respectively. The mortality parameters viz, total mortality (Z), fishing mortality (F) and natural mortality (M) rates were estimated at 1.20, 0.70 and 0.50 y-1, respectively. In Thoothukudi, the recruitment season of A. superciliosus was found during March and October showing optimal exploitation with exploitation rate (E) of 0.58 and the estimated exploitation ratio (U) was 0.54. The virtual population analysis (VPA) showed a fishing pressure on the 240 to 320 cm length group. The estimated annual catch and maximum sustainable yield (MSY) were 58 and 68 t respectively. The present study gives valuable baseline information on the fishery and population characteristics of this vulnerable and data deficit resource A. superciliosus off Thoothukudi.

Item Type:	Article
Uncontrolled Keywords:	Growth and mortality parameters, Maximum sustainable yield, Recruitment overfishing, Virtual population analysis
Subjects:	Demersal Fisheries > Shark fisheries Fish and Fisheries > Fish biology Demersal Fisheries
Divisions:	CMFRI-Tuticorin
Depositing User:	Arun Surendran
Date Deposited:	04 Jan 2022 08:20
Last Modified:	04 Jan 2022 08:20
URI:	http://eprints.cmfri.org.in/id/eprint/15649

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