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Eptatretus burgeri

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA MYXINI MYXINIFORMES MYXINIDAE

Scientific Name: Eptatretus burgeri
Species Authority: (Girard, 1855)
Common Name(s):
English Inshore Hagfish
Synonym(s):
Bdellostoma burgeri Girard, 1855
Heptatrema cirrhatum Temminck & Schlegel, 1850
Taxonomic Notes: Eptatretus burgeri was briefly described by Girard (1855) based on an illustration of a single specimen from Simabara Bay, which was previously misidentified as Heptatrema cirrhatum by Temminck and Schlegel (1850: 310, pl. 143).

Assessment Information [top]

Red List Category & Criteria: Near Threatened ver 3.1
Year Published: 2013
Date Assessed: 2009-11-09
Assessor(s): Mincarone, M.M.
Reviewer(s): Polidoro, B., Knapp, L. & Carpenter, K.E.
Justification:
This species is only known from East China Sea, where is can be common. However, it is intensively fished for its skin and for food. There has been a 70% decline in catch in at least one third of its range (1980-1995) over the past three generations (24 years). The fishery has not ceased despite low population levels. Extrapolating this across the full range of the species, there has been an estimated 23% decline since 1980. This species is listed as Near Threatened. More research is needed to determine the status of the species population.

Geographic Range [top]

Range Description: This species is found in the Western North Pacific off the coast of southern Japan, South Korea, northern and northwestern Taiwan. It probably also occurs in all of the Yellow Sea.
Countries:
Native:
China; Japan; Korea, Republic of; Taiwan, Province of China
FAO Marine Fishing Areas:
Native:
Pacific – northwest
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: This species is very common but there is little information on actual population levels and trends. In the East China Sea, although catch data is mixed and reported as aggregate for Hagfish species, the hag fishery has declined both in terms of numbers of boats and in size of catch (Gorbman et al. 1990, Honma 1998) but has increased in value. According to Honma (1998), significant decreases in the hagfish landed at Izumozaki are considered to be the result of overfishing, and represent at least one third of its range. Catch data in this area shows a 70% decline between 1980 and 1995 (Gorbman et al. 1990, Honma 1998) and effort has remained low through this period, likely as a result of low abundance levels. Fish size has also declined.
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: This is a shallow waters species living at depths from 5-270 m. It is a nocturnally active animal, with about 70% of the observed individuals uncovered and out of the burrows as compared to about 3% by day (Fernholm 1974). It is, so far, the only species of hagfish that has been found to have a certain spawning time at the population level and an annual migration to spawning grounds (Dean 1904, Kobayashi et al. 1972, Fernholm 1974, Nozaki et al. 2000). A population living at 6-10 m depth on a muddy bottom in Koajiro Bay, Kanagawa Prefecture, Japan, was not found from July to September in the shallow waters of the bay. In this period, individuals from the same population were caught in deeper waters of 50 m and 100 m, where they presumably spawn (Fernholm 1974 Nozaki et al. 2000). Tsuneki et al. (1983) described the same behaviour for specimens from Kamo Bay (about 20 m depth), south end of Dogo Island, Japan, which migrate to adjacent deepest waters (50 m) outside the bay for breeding in September. According to Tsuneki et al. (1983), of 362 specimens collected, 167 (46%) were males, 188 (52%) were females, and seven (2%) were hermaphrodites. The mean length was 50.8 cm for males and 48.9 cm for females. There were 44 mature eggs per female on average. For detailed information on the seasonal development of gonads for males and females see Conel (1931) and Nozaki et al. (2000).

This species is found in the sub-littoral zone (Yamada et al. 1995). It usually buries itself in bottom mud (Fernholm 1991). This species migrates into deeper water to spawn (Patzner 1998, Kobayashi et al. 1972). This is the only member of the family having a seasonal reproductive cycle (Patzner 1998). This species is a food fish in Japan. Its hide is processed into leather and exported worldwide, usually as 'eel' leather. The copulatory organ is absent in this animal. The gonads of hagfishes are situated in the peritoneal cavity. The ovary is found in the anterior portion of the gonad, and the testis is found in the posterior part. The animal becomes female if the cranial part of the gonad develops or male if the caudal part undergoes differentiation. If none develops, then the animal becomes sterile. If both anterior and posterior parts develop, then the animal becomes a functional hermaphrodite. However, hermaphroditism being characterised as functional needs to be validated by more reproduction studies (Patzner 1998).

The longevity of this hagfish is suggested to be 17 years from specimens in aquariums, so generation length is conservatively estimated to be eight years.
Systems: Marine

Threats [top]

Major Threat(s): This species is of economic importance due to the demand for the eel-skin leather industry in Korea. It is also targeted as it causes damage to other fishes in nets, and it is used as food in Taiwan, China, and Japan. It has been intensively fished off Korea and Japan and there has been greatly reduced catches in fish size and number over the last 20 years (McMillan and Wisner 2004).

Conservation Actions [top]

Conservation Actions: There are no known conservation measures in place but more research is needed on species population size and fisheries impact.

Citation: Mincarone, M.M. 2013. Eptatretus burgeri. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 25 July 2014.
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