Eptatretus stouti
Pacific hagfish

Eptatretus stouti (Pacific hagfish) are found in cold marine waters of the antitropical north and south Pacific Ocean on muddy sea floors. (McCrae, 1997)

Pacific hagfish are found typically on muddy bottoms to depths of 633 meters, but can also be found occasionally on rocky bottoms. They are more common at shallower depths, from 40 to 100 meters. Pacific hagfish may make small migrations from shallow waters in the fall into deeper water. Although this is unconfirmed, it is consistent with seasonal migrations in other hagfish. (Fernholm, 1998; McCrae, 1997)

Pacific hagfish resemble lampreys, being long, tubular, and pinkish grey in color. They lack fins, except for a primitive tail fin that proves useless for propulsion. Their eyes are small and reduced, but Pacific hagfish have a good sense of smell and touch. Their mouth contains a ring of short and sensitive tentacles. Hagfish do not have true jaws, but instead have two pair of rasps on the tongue used for pulling and tearing. Large slime glands run the length of their body near the degenerate lateral line. Hagfish have a partial skull and cartilagenous skeleton. They are from 30 to 63.5 cm in length and from 0.8 to 1.4 kg. Females are typically larger than males. (Broadal and Fange, 1963; McCrae, 1997)

Pacific hagfish hatch from an egg in fully functional form without any intermediate larval stage. Determining the sex of Pacific hagfish below 35 cm in length is difficult as a copulatory organ is absent. Despite over a century of searching, only 200 fertilized eggs of Eptatretus stouti have been found in Monterey Bay, California. (Broadal and Fange, 1963; Fernholm, 1998; Martini, 1998; Patzner, 1998)

Estimated life span of Pacific hagfish in the wild is 40 years, and 17 years in captivity. (Finch, 1990; King and McFarlane, 2003)

One of the most distinguishing behaviors of hagfish is the ability to produce large amounts of mucilaginous slime almost instantaneously. The slime is secreted as a defense mechanism from pores that line the sides of the body. Upon contact with seawater, the slime rapidly expands into a sticky gel that can sometimes suffocate an attacker. Hagfish also have the ability to tie a knot in their body, and slide in and out of the knot. This can be used to elude predators, to bury into a carcass, to gain leverage to tear off pieces of flesh, or clean itself of slime. (Broadal and Fange, 1963; Schewe, Stein, and Riordon, 2003)

A system of sensory organs resembling taste buds, called Schreiner organs, are found throughout the epidermis. The distribution of these organs is more extensive than taste buds in nearly any vertebrate, giving hagfish the ability to sense prey in dark and muddy habitats. This sensory system has no direct homologue in vertebrates and seems specific to hagfish. Hagfish also have well-developed nasal organs used in olfaction. (Braun, 1998; McCrae, 1997)

Pacific hagfish have two pair of primitive, yet effective, rasps on the tongue used primarily for grasping. After establishing a firm hold on a food source, the hagfish ties and unties a knot within its own body to generate a ripping force. Pacific hagfish feed on a variety of dead or dying organisms, including fish and mammals, but also probably include marine invertebrates in their diet. Male hagfish may eat hagfish eggs. (Broadal and Fange, 1963; Fernholm, 1998; McCrae, 1997)

Pacific hagfish produce large amounts of mucilaginous slime, and can tie and untie knots in their body to evade predators. The primary predators of Pacific hagfish are harbor seals (Phoca vitulina) and humans. They have also been found in the stomachs of sablefish (Anoplopoma fimbria). (Fernholm, 1998)

Pacific hagfish are crucial for eliminating dead and dying organsims, and the effect of large-scale removal on the ecosystem could be significant as hagfish are important for recycling nutrients. (Broadal and Fange, 1963; McCrae, 1997)

There are no negative impacts of Pacific hagfish on humans.

In Korea, approximately 5 million pounds of Pacific hagfish meat is consumed yearly, and in many countries the skin is commonly processed into "eelskin" accessories such as purses, wallets, and boots. Hagfish are sometimes found in public aquariums, and their very low metabolic rate is of specific research interest. (Barnaby et al., 1995; Fernholm, 1998)

Pacific hagfish remain common throughout their range.

Pacific hagfish are a member of one of the most primitive craniate groups. Pacific hagfish have changed little over the past 330 million years, and closely resemble the first craniates. The evolutionary path leading to Homo sapiens probably diverged from hagfish approximately 530 million years ago. Hagfish can go several months without eating. One adult Pacific hagfish can fill a seven-liter bucket with slime in minutes. (Broadal and Fange, 1963; Fernholm, 1998; Martini, 1998; McCrae, 1997)