• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.49 no.4
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• pp.500-504
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• 2013

A total of 24 juvenile specimens of Thunnus tonggol (5.45~7.26mm in total length) of the Sombridae were collected from the southeast sea of Jeju Island during 26~30 July, 2013. Twenty-four specimens identified T. tonggol have melanophores distributed on the 1st dorsal-fin rays, the dorsal of head and vetral side. Three individulas were identified using mitochondrial DNA cytochrome oxidase submit 1 (CO1) sequences (452 base pairs). All were identified as T. tonggol, their mtCO1 sequences being consistent with those of Thunnus tonggol (d=0.000), followed by Thunnus albacares (d=0.002) and Thunnus obesus (d=0.007).

• Fisheries and Aquatic Sciences
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• v.25 no.3
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• pp.167-174
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• 2022

Despite the beneficial aspect of fish consumption, bioaccumulation of toxic metals such as arsenic (As) and mercury (Hg) can enhance the health risk for the consumers. Arsenic and Hg concentrations were measured in edible tissue and two targeted organs, namely gill and liver of longtail tuna species (Thunnus tonggol) from Terengganu waters, including Kuala Besut, Kuala Terengganu, Dungun and Kemaman. The concentration of As and Hg were analysed by using inductively coupled plasma- mass spectrometry. The mean concentrations of both elements were significantly different (p < 0.05) among the locations and targeted organs. The hierarchy of As and Hg mean concentrations in muscle samples were Dungun > Kuala Besut > Kemaman > Kuala Terengganu. The mean concentration of As in all samples, including muscle, exceeded the permitted level set by Malaysia Food Act. Estimate Weekly Intake (EWI) was conducted to assess the health risk effect, and 63 kg was used as the average body weight of Malaysian adults. However, the EWI values show that the weekly intake of As and Hg does not exceed the provisional tolerable weekly intake limit suggested by Food and Agricultural Organization for the United Nations and is considered safe to be consumed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.4
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• pp.449-461
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• 2023

The aim of this study was to conduct an ecosystem-based fishery risk assessment of tuna fisheries in the Western Indian Ocean. We selected gillnet, purse seine, hand line, baitboat, and longline fisheries as the target fisheries method, and selected longtail tuna (Thunnus tonggol), narrow-barred Spanish mackerel (Scomberomorus commerson), kawakawa (Euthynnus affinis), skipjack tuna (Katsuwonus pelamis), yellowfin tuna (T. albacares), bigeye tuna (T. obesus), albacore tuna (T. alalunga) and swordfish (Xiphias gladius) as the target species. The risk score for the size at the first capture in sustainability objective was high, especially, for the purse seine and baitboat fisheries using the fish aggregating devices (FADs). The risk score for the bycatch in the biodiversity objective was high for the gillnet fishery, and the gillnet fisheries using FADs showed high risks for the habitat quality objective due to the loss of the fishing gears. With regards to the socio-economic benefits objective, the risk score of the sales profits was low due to high sales of the tuna fisheries. The ecosystem risk score in the Western Indian Ocean was estimated to be moderate, although management is required for some of the indicators that have high-risk scores.