1. Hammerhead sharks are represented by four species in India's marine fishery – Sphyrna lewini, Sphyrna mokarran, Sphyrna zygaena and Eusphyra blochii. This paper describes the hammerhead shark fishery in India during 2007–2018 and summarizes observations on the biology of S. lewini exploited along the Indian coast.
2. Hammerhead sharks are caught by trawl nets, gillnets, seines and line gear, mostly as bycatch. Annual average landing of hammerhead sharks during 2007–18 was 639 t, with a low of 290 t in 2018, of which S, lewini was the dominant species, comprising 95% of landings. Hammerhead sharks formed nearly 1.31% of the total elasmobranch landings. About 54% of hammerhead sharks were landed by trawlers.
3. Length range of S. lewini in regular landings was 36–300 cm total length (TL). The dominant size class was 30–100 cm TL; 79.5% of males and 83.2% of females measured between 40 and 100 cm TL. Length–weight relationship was derived as W = 0.0218*(L)^2.634 and W = 0.0131*(L)^2.769 for males and females, respectively.
4. Overall sex ratio (F: M) was 1.3:1; below 100 cm TL, the sex ratio was skewed in favour of females. The length at first maturity of males was estimated as 168 cm. The length at first maturity of females was estimated at 239.6 cm. Fecundity ranged from 12–40, size at birth was 36–45 cm TL. Bony fishes were the preferred prey, followed by cephalopods.
5. The S. lewini landings in India are dominated by juveniles and threatens sustainability of the stock. Capture of juvenile sharks can be excluded to a considerable extent through strict implementation of minimum legal size of capture, and a conservative minimum legal size of 220 cm is suggested for this species in Indian waters. Identification of recurring juvenile aggregation grounds, their spatio-temporal closures, gear restrictions and greater stakeholder awareness could lead to conservation of the resource and a sustainable fishery.

中文翻译：

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印度水域双髻鲨（Carcharhiniformes：Sphyrnidae）渔业的状况以及对扇形双髻鲨 Sphyrna lewini 生物学的观察（格里菲斯和史密斯，1834 年）

1. 锤头鲨在印度的海洋渔业中有四种代表——Sphyrna lewini、Sphyrna mokarran、Sphyrna zygaena和Eusphyra blochii。本文描述了 2007 年至 2018 年间印度的双髻鲨渔业，并总结了对沿印度海岸开采的S. lewini生物学的观察结果。
2. 锤头鲨被拖网、刺网、围网和渔具捕获，主要是作为副渔获物。2007-18 年双髻鲨的年平均上岸量为 639 吨，2018 年最低为 290 吨，其中S、lewini是优势物种，占上岸量的 95%。锤头鲨占总弹鳃类动物的近 1.31%。大约 54% 的双髻鲨被拖网渔船捕获。
3. S. lewini在常规着陆中的长度范围为 36-300 厘米总长度 (TL)。主要尺寸等级为 30-100 cm TL；79.5% 的男性和 83.2% 的女性测量的 40 到 100 厘米 TL 之间。男性和女性的体长-体重关系分别为 W = 0.0218*(L) ^2.634和 W = 0.0131*(L) ^2.769。
4. 总体性别比（F:M）为1.3:1；低于 100 cm TL，性别比例偏向雌性。雄性首次成熟时的长度估计为 168 厘米。雌性首次成熟时的长度估计为 239.6 厘米。繁殖力范围为 12-40，出生时体长为 36-45 cm TL。硬骨鱼是首选的猎物，其次是头足类动物。
5. 印度的S. lewini上岸以幼鱼为主，威胁到种群的可持续性。通过严格执行捕捞的最小合法尺寸，可以在相当大的程度上排除对幼鲨的捕获，并且建议在印度水域对该物种的最小合法尺寸为 220 厘米。确定经常出现的幼鱼聚集地、它们的时空关闭、渔具限制和更高的利益相关者意识，可能会导致资源保护和可持续渔业。