Shark bycatch in the experimental tuna longline fishery in Lakshadweep Sea, India

Kumar, K. V. Aneesh; Pravin, P.; Meenakumari, B.; Khanolkar, P.S.; Baiju, M.V.

doi:10.1111/jai.12682

Cited by 9 publications

(8 citation statements)

References 28 publications

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“…[ 5 , 71 ]), while shark bycatch can be especially high in tropical waters (e.g. [ 72 , 73 ]). With such variability, it is difficult to make a robust estimate of total bycatch.…”

Section: Discussionmentioning

confidence: 99%

Bycatch in the Maldivian pole-and-line tuna fishery

et al. 2017

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Tropical tuna fisheries are among the largest worldwide, with some having significant bycatch issues. However, pole-and-line tuna fisheries are widely believed to have low bycatch rates, although these have rarely been quantified. The Maldives has an important pole-and-line fishery, targeting skipjack tuna (Katsuwonus pelamis). In the Maldives, 106 pole-and-line tuna fishing days were observed between August 2014 and November 2015. During 161 fishing events, tuna catches amounted to 147 t: 72% by weight was skipjack, 25% yellowfin tuna (Thunnus albacares) and 3% other tunas. Bycatch (all non-tuna species caught plus all tuna discards) amounted to 951 kg (0.65% of total tuna catch). Most of the bycatch (95%) was utilized, and some bycatch was released alive, so dead discards were particularly low (0.02% of total tuna catch, or 22 kg per 100 t). Rainbow runner (Elagatis bipinnulata) and dolphinfish (Coryphaena hippurus) together constituted 93% of the bycatch. Live releases included small numbers of silky sharks (Carcharhinus falciformis) and seabirds (noddies, Anous tenuirostris and A. stolidus). Pole-and-line tuna fishing was conducted on free schools and schools associated with various objects (Maldivian anchored fish aggregating devices [aFADs], drifting FADs from western Indian Ocean purse seine fisheries, other drifting objects and seamounts). Free school catches typically included a high proportion of large skipjack and significantly less bycatch. Associated schools produced more variable tuna catches and higher bycatch rates. Fishing trips in the south had significantly lower bycatch rates than those in the north. This study is the first to quantify bycatch rates in the Maldives pole-and-line tuna fishery and the influence of school association on catch composition. Ratio estimator methods suggest roughly 552.6 t of bycatch and 27.9 t of discards are caught annually in the fishery (based on 2015 national catch), much less than other Indian Ocean tuna fisheries, e.g. gillnet, purse-seine, and longline.

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“…[ 5 , 71 ]), while shark bycatch can be especially high in tropical waters (e.g. [ 72 , 73 ]). With such variability, it is difficult to make a robust estimate of total bycatch.…”

Section: Discussionmentioning

confidence: 99%

Bycatch in the Maldivian pole-and-line tuna fishery

et al. 2017

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“…amblyrhynchos and N . ferrugineus have been reported from India (Joshi et al , ; Kumar et al , ), and for these species and T . obesus in Indonesia (White, ).…”

Section: Threatsmentioning

confidence: 94%

Reef sharks: recent advances in ecological understanding to inform conservation

Osgood

Baum

2015

Journal of Fish Biology

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Sharks are increasingly being recognized as important members of coral-reef communities, but their overall conservation status remains uncertain. Nine of the 29 reef-shark species are designated as data deficient in the IUCN Red List, and three-fourths of reef sharks had unknown population trends at the time of their assessment. Fortunately, reef-shark research is on the rise. This new body of research demonstrates reef sharks' high site restriction, fidelity and residency on coral reefs, their broad trophic roles connecting reef communities and their high population genetic structure, all information that should be useful for their management and conservation. Importantly, recent studies on the abundance and population trends of the three classic carcharhinid reef sharks (grey reef shark Carcharhinus amblyrhynchos, blacktip reef shark Carcharhinus melanopterus and whitetip reef shark Triaenodon obesus) may contribute to reassessments identifying them as more vulnerable than currently realized. Because over half of the research effort has focused on only these three reef sharks and the nurse shark Ginglymostoma cirratum in only a few locales, there remain large taxonomic and geographic gaps in reef-shark knowledge. As such, a large portion of reef-shark biodiversity remains uncharacterized despite needs for targeted research identified in their red list assessments. A research agenda for the future should integrate abundance, life history, trophic ecology, genetics, habitat use and movement studies, and expand the breadth of such research to understudied species and localities, in order to better understand the conservation requirements of these species and to motivate effective conservation solutions.

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“…Similar results were also obtained by [12] in a trial of tuna longline in Japanese waters with a dominant catch of blue sharks (more than 90% of the total catch of sharks), and [13] in the North Atlantic waters with catches of blue sharks reaching 52% of the total fish catch. Different results were reported by [14] with grey reef shark as the dominant catch reaching 89.9%, and [15] with whaler sharks reaching 50% of the total catch in Indian marine waters.…”

Section: 80mentioning

confidence: 72%

The shark by-catch of tuna longline fisheries in Southern Indian Ocean of Java, Indonesia

2018

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In relation to the achievement of the target SDG’s No. 14, the sustainable shark fisheries management need to implement. As a part of the tuna fisheries by-catch, a high number of shark resources have been caught in the Indian Ocean waters. One of the main vessels of tuna catchers in the Southern Indian Ocean of Java is the tuna longline from Cilacap. This paper aims to analyze the shark by-catch of tuna longline in the Indian Ocean in the south Java that landed in Cilacap. The research data was obtained from daily recording activities of fishing vessel loading activities by Cilacap Ocean Fisheries Port staff during the period of 2013-2017. The analysis was done through data tabulation, graphical approaches, and data trend analysis through the availability of time series data. The data analyzed include fleet development, fishing ground, catch composition and CPUE value. The results of the analysis show that there are about eight species of sharks that are by-catch of tuna longline from Cilacap. The highest shark by-catch occurred in April with CPUE averaging 9 kg/day/vessel. The blue shark (Prionace glauca) is the dominant shark catch which reaches 66% of the total sharks catch.

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Shark bycatch in the experimental tuna longline fishery in Lakshadweep Sea, India

Cited by 9 publications

References 28 publications

Bycatch in the Maldivian pole-and-line tuna fishery

Bycatch in the Maldivian pole-and-line tuna fishery

Reef sharks: recent advances in ecological understanding to inform conservation

The shark by-catch of tuna longline fisheries in Southern Indian Ocean of Java, Indonesia

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