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Euthynnus affinis

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA ACTINOPTERYGII PERCIFORMES SCOMBRIDAE

Scientific Name: Euthynnus affinis
Species Authority: (Cantor, 1849)
Common Name(s):
English Kawakawa, Eastern Little Tuna, Black Skipjack, Mackerel Tuna, Oceanic Bonito, Bonito
French Bonite à Dos Rayé, Bonite, Bonite D'Inde, Petit Thon, Thonine, Thonine Orientale
Spanish Bacoreta, Bacoreta Oriental, Bonito
Synonym(s):
Euthynnus yaito Kishinouye, 1915
Thynnus affinis Cantor, 1849
Wanderer wallisi Whitley, 1937

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2011
Date Assessed: 2009-12-04
Assessor(s): Collette, B., Chang, S.-K., Fox, W., Juan Jorda, M., Miyabe, N., Nelson, R. & Uozumi, Y.
Reviewer(s): Russell, B. & Polidoro, B.
Justification:
This species is widespread and abundant in the Indian and Western Pacific Ocean. It is caught in commercial fisheries, primarily as bycatch. It is marketed in a variety of products, and reported worldwide landings are increasing. Currently, there is no information on population trends. It is listed as Least Concern. More information is needed on this species population and the impact of fisheries, especially as it seems that many catches are not being reported.
For further information about this species, see TUNAS_SkiJumpEffect.pdf.
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Geographic Range [top]

Range Description: This is an Indo-West Pacific species. It is found in warm waters including oceanic islands and archipelagos. A few stray specimens have been collected in the eastern tropical Pacific (Collette and Nauen 1983).
Countries:
Native:
Australia; Bangladesh; Brunei Darussalam; China; Christmas Island; Comoros; Cook Islands; Djibouti; Egypt; Eritrea; Fiji; French Polynesia; Guam; Hong Kong; India; Indonesia; Iran, Islamic Republic of; Japan; Jordan; Kenya; Kiribati; Madagascar; Malaysia; Maldives; Marshall Islands; Mauritius; Micronesia, Federated States of ; Mozambique; Myanmar; New Caledonia; Northern Mariana Islands; Oman; Pakistan; Palau; Papua New Guinea; Philippines; Réunion; Samoa; Saudi Arabia; Seychelles; Singapore; Solomon Islands; Somalia; South Africa; Sri Lanka; Sudan; Taiwan, Province of China; Tanzania, United Republic of; Thailand; Tokelau; Tonga; Tuvalu; Vanuatu; Viet Nam; Yemen
FAO Marine Fishing Areas:
Native:
Atlantic – southeast; Indian Ocean – eastern; Indian Ocean – western; Pacific – eastern central; Pacific – northwest; Pacific – southwest; Pacific – western central
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The reported world catch for this species between 1975 and 1981 fluctuated between 44,000 and 65,000 metric tonnes per year. The countries with the largest landings are currently the Philippines and Thailand (FAO 2009). In the Philippines and Indonesia, the catch includes many small individuals (N. Miyabe pers comm 2009).This species is considered abundant in many parts of its range.

Worldwide reported landings show a gradual increase from 20,400 tonnes in 1950 to 282,359 tonnes in 2006 (FAO 2009). There are only sub-regional stock assessments for this species, generally based on short time series. For example, in Sri Lanka this species was considered to not be fully exploited (Dayaratne and Silva 1991). Based on a length-structured VPA for 2003–2006 in Veravel, India, it seemed likely that maximum yield and yield/recruit could be obtained by increasing the amount of fishing by 80% (Ghosh et al. 2010).

There is no information on stock structure in the Indian Ocean. From 1958–2007, catches in the Indian Ocean have increased from 3,000 to 125,000 tonnes (IOTC 2007).
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: This pelagic and oceanodromous species occurs in open waters, but it always remains close to the shoreline. It is found to 50 m depth. The young may enter bays and harbours. It forms multi-species schools by size with other scombrid species, comprising from 100 to over 5,000 individuals. It is a highly opportunistic predator feeding indiscriminately on small fishes, especially on clupeoids and atherinids (e.g., 78% by weight, 71% frequency in eastern Australia, Griffiths et al. 2009). It also feeds on squids, crustaceans and zooplankton (Collette 2001).

Yesaki and Arce (1994) and Muthias (1985) report the apparent length at 50% maturity for this species off India to be 43 cm. A study conducted in Taiwan found the age at first maturity to be two years (Chiou et al. 2004). Longevity has been estimated at six years (Landau 1965).

This species spawns extensively, both geographically and temporally, throughout its range (Schaefer 2001). Although spawning distributions of all three Euthynnus species have been reported to be restricted primarily to peripheral areas and around islands (Yoshida 1979, Nishikawa et al. 1985), spawning in the eastern tropical Pacific has been shown to be widely distributed from coastal to oceanic waters (Schaefer 1987).

Maximum Size is 100 cm fork length (FL), about 13.6 kg. The all-tackle game fish record is of a 13.15 kg fish caught off Isla Clarion, Revillagigedo Islands, Mexico, in the eastern Pacific outside the usual range of this Indo-West Pacific species (IGFA 2011).
Systems: Marine

Use and Trade [top]

Use and Trade: This species is generally marketed canned and frozen. It is also utilized dried, salted, smoked (Collette 2001) and fresh. It is important in highly commercial fisheries. This species is used in pet food for dogs and cats.

Threats [top]

Major Threat(s): There are no major threats to this species. It is occasionally caught in multi-species fisheries, mainly by surface trolling; also with gill nets and purse seines. It is also caught as bycatch in industrial purse seines. It seems that there are many catches of this species that are not reported, for example it is caught in Madagascar and Zanzibar (Tanzania).

Conservation Actions [top]

Conservation Actions: There are no known conservation measures for this species. This is listed as a highly migratory species in Annex I of the 1982 Convention on the Law of the Sea (FAO Fisheries Department 1994). More information is needed on this species population and the impact of fisheries, especially as it seems that many catches are not being reported

Citation: Collette, B., Chang, S.-K., Fox, W., Juan Jorda, M., Miyabe, N., Nelson, R. & Uozumi, Y. 2011. Euthynnus affinis. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 21 November 2014.
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