Regularity: Regularly occurring
Type of Residency: Year-round
The Eastern Pacific population is recognized as a subspecies, Auxis thazard brachydorax (Collette and Aadland 1996), which occurs from California to the mouth of the Gulf of California to Peru, and all the oceanic islands except Clipperton (Robertson and Allen 2006).
Habitat Type: Marine
Habitat and Ecology
Longevity is approximately four years. The smallest maturing female off the west coast of Thailand was 31â33 cm fork length (FL), and the length at 50% maturity in the Gulf of Thailand was 34â37 cm FL (Yesaki and Arce 1994, Collette 2010). Length at maturity 50% is 30.5 cm FL in India (Muthiah 1985). Average estimated length-age relationships in the equatorial Atlantic are 22.9 cm at one year, 30.4 cm at two years, 36.7 cm at three years and 40.4 cm at four years (Grudtsev and Korolevich 1986).
Fecundity estimates range from 78,000 to 1.37 million eggs in 31.5â44.2 cm females. In correlation with temperature and other environmental changes, the spawning season varies with areas, but in some places it may even extend throughout the year. In the southern Indian Ocean, spawning extends from August to April, north of the equator from January to April at sea surface temperatures of 24Â°C or higher (Klawe 1963, Collette 2010).
Maximum Size is 62 cm FL. The all-tackle game fish record is of a 1.72 kg fish caught off Hat Head, New south Wales, Australia in 1998 (IGFA 2011).
Depth range (m): 0 - 237
Depth range (m): 0 - 237
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.
Non-Migrant: No. All populations of this species make significant seasonal migrations.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
Molecular Biology and Genetics
Barcode data: Auxis thazard
Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
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Download FASTA File
Statistics of barcoding coverage: Auxis thazard
Public Records: 52
Specimens with Barcodes: 73
Species With Barcodes: 1
National NatureServe Conservation Status
Rounded National Status Rank: NNR - Unranked
NatureServe Conservation Status
Rounded Global Status Rank: GNR - Not Yet Ranked
IUCN Red List Assessment
Red List Category
Red List Criteria
FAO does not report statistics for this species. Auxis spp. catches are generally not identified to species. Worldwide reported landings for Auxis spp show a gradual increase from 22,278 t in 1950 to 256,325 t in 2006 (FAO 2009).
In the Atlantic, most catches reported as A. thazard are probably A. rochei. The International Commission for the Conservation of Atlantic Tunas (ICCAT) includes statistics for Frigate Tuna (Auxis thazard) which are suspected to include both A. rochei and A. thazard. In the total catch of Frigate Tuna, the proportion of each of the two species is not known. Recent ICCAT estimates (ICCAT 2009) range from 21,000 (1987) to 3500 (2008) t. This species may be less abundant than A. rochei in the Atlantic.
In the Mediterranean, this is a common species in fisheries and abundance changes from place to place every year (Di Natale pers. comm. 2008). No assessment summary is given for this species from the Mediterranean. The General Fisheries Commission for the Mediterranean (GFCM) is now starting a project to collect data on small tuna-like species in the Mediterranean (Di Natale pers. comm. 2008).
In the 1980s there was a marked increase in reported landings of all small tuna species combined compared to previous years, reaching a peak of about 139,412 t in 1988. Reported landings for the 1989â1995 period decreased to approximately 92,637 t, and since then values have oscillated, with a minimum of 69,895 t in 1993 and a maximum of 123,600 t in 2005. Declared catches were 79,228 t in 2006 and 74,087 t in 2007. A preliminary estimate of the total nominal landings of small tunas in 2008 is 55,876 t. The 2008 preliminary catch of small tuna amounted to 55,876 t, of which 6,018 t was Bullet Tuna (Auxis rochei) (STECF 2009). There are more than 10 species of small tunas, but only five of these account for about 88% of the total reported catch by weight. These five species are: Atlantic Bonito (Sarda sarda), Frigate Tuna (Auxis thazard) which may include some catches of Bullet Tuna (Auxis rochei), Little Tunny (Euthynnus alletteratus), King Mackerel (Scomberomorus cavalla), and Atlantic Spanish Mackerel (Scomberomorus maculatus) (ICCAT 2009).
The catch for 2007 of this species in the Indian Ocean was 41,700 tonnes compared to 3,700 tonnes of A. rochei (IOTC 2007).
Overall trends in the small tuna catch may mask declining trends for individual species because annual landings are often dominated by the landings of a single species. These fluctuations seem to be partly related to unreported catches, as these species generally comprise part of the bycatch and are often discarded, and therefore do not reflect the real catch. It is commonly believed that catches of small tunas are strongly affected by unreported or underreported data in all areas. Small tunas are exploited mainly by coastal fisheries and often by artisanal fisheries, although substantial catches are also made, either as target species or as bycatch, by purse seiners, mid-water trawlers, handlines, troll lines, driftnets, surface drifting long-lines and small scale gillnets. Several recreational fisheries also target small tunas. Since 1991, the use of fish aggregating devices (FADs) by tropical purse seiners may have led to an increase in fishing mortality of small tropical tuna species (STECF 2009). There is a general lack of information on the mortality of these species as bycatch, exacerbated by the confusion regarding species identification (ICCAT 2009).
Data on the catch composition, biology and trends are now available from the Mediterranean and the Black Sea, thanks to the ICCAT/GFCM joint expert group in 2008. More information, particularly on specific fishing effort, is needed from all areas. The small tuna fishery seems to be quite important for the coastal communities, both economically and as a source of proteins. The ICCAT Standing Committee on Research and Statistics (SCRS) suggests that countries be requested to submit all available data to ICCAT as soon as possible, in order to be used in future meetings. No management recommendations have been presented by ICCAT due to the lack of proper data, historical series and analyses. ICCAT/SCRS, in 2008, reiterated its recommendation to carry out studies to determine the state of these stocks and the adoption of management solutions. ICCAT-SCRS in 2009 noted that there is an improvement in the availability of catch and biological data for small tuna species particularly in the Mediterranean and the Black Sea. However, biological information, catch and effort statistics for small tunas remain incomplete for many of the coastal and industrial fishing countries. Given that, many of these species are of high importance to coastal fishermen, especially in some developing countries, both economically and often as a primary source of proteins, therefore the SCRS recommends that further studies be conducted on small tuna species due to the limits of information available (STECF 2009).