Download
1 / 21
220 likes | 455 Views
Hagfish. Class Myxini, Hagfish. Members of the class Myxini have a partial cranium (skull), but no vertebrae. Their skeleton is made of cartilage, as is that of sharks.
E N D
Class Myxini, Hagfish Members of the class Myxini have a partial cranium (skull), but no vertebrae. Their skeleton is made of cartilage, as is that of sharks. Hagfish lack jaws, and for this reason used to be classified with the lampreys in a group called the Agnatha ("no jaws") or the Cyclostomata ("round mouth").
Names and size • Common Name(s):Hagfish • Scientific Name:Myxine glutinosa • Usual Size:up to 45cms.
Hagfish facts • Breeding: A hermaphrodite, which lays numerous, large eggs in a hard case. It is unlikely that these fish are self-fertilizing hermaphrodites and need a partner to breed. • Habitat:Hagfish are found in all depth of water and lie buried in fine sands or silt when not feeding • Food:Most fish, living or dead. Hagfish are the first fish to find their way to any dead animals which find their way to the seabed. They are parasitic on live fish, attaching themselves to the side and slowly eating their way through the fish. It has been known to find Cod with as many as 30 young Hagfish attached to them.
Additional Notes: • Hagfish belong to the group of primitive, jawless fish which includes the marine and freshwater lampreys. They are considered a threat to commercial fish stocks of the North Sea because if the fish are not killed outright by the attacks, they usually succumb to later infections caused by the large wounds left by the Hagfish.
Notes… An unmistakable eel-like body that is uniformly pink in color. The mouth is a slit surrounded by fringe of short, fleshy barbels. A fleshy fin runs from the vent to the rear portion of the back, and a row pores runs along both sides from the head to the tail. A thick layer of glutinous slime (hence specific name) covers the whole body and can be sloughed in copious amounts when handled
Slime ducts Hagfish - note the row of ducts located ventrally along the body for the exit of mucous from the numerous slime glands
Deep sea livingHagfish Eptatretus(probably deani, depth107-2743m, mainly 250-1200m).
Rattail or Grenadier fish: Termed benthopelagic fish because they swim just above the bottom, these relatives of cod are the most common fish of bathyl and abyssal habitats. The deepest grenadier observed lives down to 6500m.Rattails have huge heads, large eyes, and long tapered tails. They have swim bladders--which may be used to make sound as well as to float--and cruise slowly above the bottom searching for live animals and carcasses to eat. The Russians have been catching these fish for food for many years now, and their numbers are declining in their waters. For a recent article on such deep-sea fishing, see New Scientist, Nov. 8, 1997.
Skates: These soft-nosed cartilaginous fish are inhabitants of the continental slopes. Like the common skates of shallow waters, they are carnivores that rest on the bottom and swim with their "wings," and lay eggs in capsules (above) that look like a piece of algal detritus. Possibly the deepest-dwelling skate is Rajella bigelowi from the North Atlantic (300-4100m).
Urochordata Tunicates and Lancelets
