Myxini (hagfishes) > Myxiniformes
(Hagfishes) > Myxinidae
(Hagfishes) > Eptatretinae
Etymology: Eptatretus: Greek, epta = seven + Greek, tretos, -e, -on = with holes (Ref. 45335); grouseri: Named for David 'Grouser' McMillan, Chief Engineer in the U.S. Merchant Marine, for his continued encouragement of C.B. McMillan's hagfish studies and for his knowledge and love of ships and the seas (Ref. 31788).
Environment: milieu / climate zone / depth range / distribution range
Marine; bathydemersal; non-migratory; depth range 648 - 722 m (Ref. 55621). Deep-water
Southeast Pacific: endemic in Galapagos Islands.
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 37.8 cm TL male/unsexed; (Ref. 31788)
Morphology | Morphometrics
Five or six gill pouches and apertures each side, last gill aperture confluent with the pharyngocutaneous duct on the left side. Multicusps 3 in anterior and 2 in posterior rows, 9 unicusps in each anterior and 8 in each posterior row, total cusps 44; slime pore counts: prebranchial 12-13, branchial 4-5, trunk 44-46, tail 14-15, total slime pores 76-77. Ventral finfold vestigial; caudal finfold well developed (Ref. 31788).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Copulatory organ absent. 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 (Ref. 51361 ).
McMillan, C.B., 1999. Three new species of hagfish (Myxinidae, Eptatretus) from the Galápagos Islands. Fish. Bull. 97:110-117. (Ref. 31788)
IUCN Red List Status (Ref. 123251)
CITES (Ref. 118484)
Threat to humans
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingMass conversion
Estimates based on models
Preferred temperature (Ref. 115969
): 6.9 - 11.2, mean 9.5 °C (based on 7 cells).
Phylogenetic diversity index (Ref. 82805
= 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00204 (0.00094 - 0.00444), b=2.93 (2.74 - 3.12), in cm total length, based on LWR estimates for this (Sub)family-body shape (Ref. 93245
Trophic level (Ref. 69278
): 4.2 ±0.5 se; based on size and trophs of closest relatives
Resilience (Ref. 120179
): Low, minimum population doubling time 4.5 - 14 years (Fec assumed to be <100).
Vulnerability (Ref. 59153
): Low to moderate vulnerability (30 of 100) .