The Atlantic hagfish or “slime
eel”, Myxine glutinosa, is found in deep, cold
waters to depths of at least 1100 m. In the western north Atlantic,
hagfish are distributed from Davis Straits, Greenland to the continental
slope waters off of Florida. In the Gulf of Maine the distribution
of hagfish is primarily affected by salinity, temperature and
substrate type (Collette and Klein-MacPhee 2002).
Hagfish is considered to be the most primitive
vertebrate species either living or extinct (Collette and Klein-MacPhee
2002, Powell et al 2005). Hagfish evolved over at least 300 million
years and have the same basic morphological traits of fossilized
specimens (Bardack 1991).
lack bones, paired fins, and a true jaw. The hagfish skeleton is
composed of cartilage, the dorsal
fin is actually a skin fold, and the jaw is a rasping plate with
horn-like teeth. Atlantic hagfish belong
to the family Myxinidae which have one pair of gill openings attached
to 6-7 internal gill pouches per opening. The species has paired
barbels on the tip of its snout and four barbels surrounding the
mouth. Hagfish are almost blind because their eyes are rudimentary
but their sense of smell is keen. The skin of the Atlantic hagfish
is smooth and scale-less with a series of slime glands along both
sides of the ventral midline (Collette and Klein-MacPhee 2002).
These glands produce fibrous mucus that protects hagfish from predators
and possibly parasites.
Atlantic hagfish inhabit soft clay or muddy
sediments and spend much of their time in temporary burrows in
the sea floor (Collette and Klein-MacPhee 2002). They prey primarily
on shrimp, worms and small crabs (Gustafson 1935, Shelton 1978,
Collette and Klein-MacPhee 2002). They are also scavengers that
feed upon dead and dying fish, mammals and shellfish. Hagfish
are often considered a nuisance by commercial fishermen because
they can feed on targeted species (Martini et al 1997, Collette
and Klein-MacPhee 2002).
Age at maturity and life expectancy are unknown
in the Gulf of Maine, as are spawning locations. Length at 50%
maturity for Grand Banks hagfish is estimated at 378 mm (Grant
2006). Spawning may occur at any time of year, as females have
been observed in various stages of oogenesis during all seasons
(Collette and MacPhee 2002, Martini et al 1997). Hagfish can possess
both mature male and female sexual organs but it is unknown if
both are functional at the same time (Powell et al 2005). Females
produce clutches containing an average of 20-30 yolky eggs (Collette
and MacPhee 2002). Time required to develop a clutch of eggs is
unknown but has been estimated at 1-2 years. Development from
egg to hatchling may be several months based on egg yolk volume
(NEFSC 2003). Studies in the Gulf of Maine suggest that the population
is composed of 10% sexually immature individuals, 59% females,
roughly 6% males and approximately 25 % of the adult population
of unknown gender (Martini et al 1997).
Although a hagfish fishery exists in the Gulf
of Maine, the resource is not actively managed at present.
In the western Pacific Ocean a
fishery for hagfish has existed since World War II. Overharvesting
lead to the expansion of hagfish fisheries into the eastern Pacific
off the northwestern US and British Columbia, and then during the
late 1980’s to the mid 1990’s to the western Atlantic
off of Maritime Canada and New England. Hagfish are utilized as
a food source and their skins are valued for leather products. All
hagfish are exported whole to Korea (NEFSC 2003).
In the Gulf of Maine (GOM), Atlantic
hagfish are caught using modified 55-gallon plastic barrels, called
hagfish pots, attached to sinking line and buoys. Typically 20-40
traps are deployed in a string for a small commercial vessel and
80-200 traps for larger vessels (NEFSC 2003). A series of funneled
holes in the side of the barrel allow hagfish to enter the baited
pot but doesn’t allow them to escape. Several rows of 3/8”
holes allow smaller animals to escape the traps.
Reporting of Atlantic hagfish
landings is presently not required by law and fishery data are therefore
incomplete. Atlantic hagfish landings first appear in the NEFSC
commercial database in 1993 with a reported landing of approximately
500 metric tons. Annual reported landings during 1994-2000 ranged
between 1,100 and 3,000 metric tons with a peak in 2000 (Table
Reported commercial hagfish
trips ranged from 94 trips in 1994 to 863 trips in 1996 and averaged
slightly above 400 trips per year during 1994-2000 (Figure
29.3 Data]). Landings during 2001 to 2005 have ranged
from 700-1,300 metric tons per year (Figure
29.2 Data]). Trips targeting Atlantic hagfish declined after
2001, averaging 253 per year (Figure
29.3 Data]). The NMFS Logbook database indicated that
the number of vessels in the hagfish fishery peaked at 23 vessels
in 1996 and 22 vessels in 2000 (Figure
29.4 Data]). Since 2000 there has been a steady decline of vessels
reporting landings, with only 6 vessels reporting in 2005.
A data collection program has
been proposed for Atlantic hagfish by NMFS requiring seafood dealers
to acquire permits and report on the purchase of hagfish made from
commercial fishing vessels to aid in the future management of this
species (Federal Register 2006).
Vessel Survey Indices
are encountered infrequently in the NEFSC research vessel Bottom
Trawl Surveys. The stratified mean number per tow index in the
Spring NEFSC survey series peaked in the mid-1970’s and
remained low ever since (Figure
29.5 Data]). A slight increase in 2001 and 2002 was observed
but the index subsequently declined.
NEFSC autumn survey abundance
indices are generally higher than in the spring (Figure
29.6 Data]). The autumn indices peaked in the early 1970’s
and were low during 1980’s. Recent indices are among the
highest in the autumn time series.
Bardack, D. 1991. First fossil
hagfish (Myxinoidea): A record from the Pennsylvanian of Illinois.
Science, vol. 254:701-703.
Collete, B. B., and G. Klein-MacPhee
(Editors). 2002. Bigelow and Schrodeder’s Fishes of the Gulf
of Maine. 3rd Edition. Smithsonian Institution Press, Washington,
“Fisheries of the the Northeastern
United States; Regulatory Amendment to Modify Recordkeeping and
Reporting and Observer Requirements.” Federal Register v71
n211 (01 November 2006): 64214-64216.
Gustafson, G. 1935. On the biology
of Myxine glutinosa L. Arkiv for Zoologi, vol. 28, pp.
Grant, S.M. 2006. An exploratory
fishing survey and biological resource assessment of Atlantic hagfish
(Myxine glutinosa) occurring on the southwest slpoe of
the Newfoundland Grand Bank. J. Northw. Atl. Fish. Sci., v 36: 91-110.
Martini, F. M. Lesser and J.B.
Heiser. 1997. A population profile for Atlantic hagfish, Myxine
glutinosa (L.), in the Gulf of Maine. Part I: Morphometrics
and reproductive state. Fishery Bulletin 95:311-320.