Hagfish "Myxine Glutinosa"...
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Taxonomy
- Domain: Eukarya
- Kingdom:Animalia
- Phylum:Chordata
- Subphylum:Vertebrata
- Class:Agnatha
- Order:Myxiniformes
- Family:Myxindae
Body Structure
Hagfish are vertebrates, with bilateral symmetry.
They strongly resemble large, slimy worms.
They usually grow from about 1 1/2 to 2 feet.
Hagfish weigh 60-105 grams.
Unlike other fish, they have no jaws, scales, or fins.
Their skeleton is mostly cartilaginous.
Of course they have no legs because they are fish.
They have poorly developed, almost blind eyes.
Their tail is slightly finned, helping them swim.
They also have at least seven gill slits on each side of their body, enabling them to breathe as water flows in and out.
Life Cycle
Fertilization occurs externally.
A female lays from 19-30 eggs on the ocean floor.
A male comes and releases his sperm on the eggs.
A hagfish hatches directly into a miniature version of the adult.
There is no larval state.
Adults do not care for the babies.
Babies mature into adults, and when a hagfish with a mate is in season, the cycle starts all over again.
Habitat
Hagfish usually are found in deep bodies of water such as seas,oceans, and straits.
They can also be found on several coasts.
Hagfish are happiest when in cool, marine, temperatures, 50 degrees F or less.
Where In The World It Lives
Hagfish are mainly found in Norway.
Two other places where they have been found are southern Newfoundland, and outer Nova Scotia, in Canada.
They are also commonly found in the Gulf of Maine.
Fishermen have spotted it in the deeper parts of the Massachussets Bay.
They are found also in Arctic seas, and the Pacific and Atlantic Oceans.
Functions
The four major functions of an animal are obtaining food and oxygen, maintaining homeostasis, moving, and reproducing.
They need food and oxygen to have energy and stay alive.
They can't make their own food like plants, so eat other organisms.
If they do not keep a stable internal environment, they will eventually die.
They have different adaptions that help keep their body cool.
Animals have to move to meet the needs of survival and reproduction.
No animal is immortal.
This is why they have to reproduce.
If they don't, their species will die off.
Movement
Hagfish do not have true fins, except for tail fins.
They glide along the muddy ocean floor in figure eight and wormlike motions.
The notochord determines the passive, mechanical motion of the hagfish.
These fish need to move to get away from predators, like marine mammals and humans.
They also need food and consume dead fish and the tiny bristleworms.
Obtaining Oxygen
Hagfish have several gill slits on both sides of their body.
The fish gulp in the water as they swim.
Water goes through the throat and into the gills.
Because gills contain blood vessels, oxygen in the water goes straight to the blood.
Carbon dioxide moves out of the blood and into the water, as waste.
The rest flows over the gills, and out through the slits under the gills.
Obtaining food/Digestion
Hagfish mainly eat two things: bristleworms, and the insides of dead or decaying fish.
Unlike their cousins, the lamprey eels, they are free-living scavengers.
They burrow into their prey, and eat them from the inside out.
This is where digestion begins.
Their digestive system is complete, which means food goes in the mouth and out the anus.
Hagfish use two tooth-like rasps on top of their tongue to scrape the flesh off dead fish.
As the food goes down the esophagus, it is digested.
Hagfish have no stomach, instead, just a long gut.
This is where food is broken down even further.
Food not used is excreted through the anus.
Reproduction
Hagfish do not have separate sexes.
The male portion of the sex organs matures in an individual, while the female portion remains undeveloped, or vice versa.
Hagfish have sexual reproduction by copulation.
The two come together after the female lays her eggs.
The male releases his sperm on the eggs, fertilizing them.
Hagfish migrate to other places to lay their eggs, usually 19-30.
Many scientists do not know the reproductive pattern of hagfish, due to their inaccessability.
Maintaining Homeostasis
Hagfish have many adaptions that allow them to keep a stable enviroment.
One is, they are ectotherms.
This means they can't make their own body heat.
Body temperature conforms to the enviroment.
They also have sharp rasps on their tongues that allow them to scrape the dead flesh right off the bones of their prey.
Hagfish eyes are so underdeveloped, some scientists have even proclaimed them to be blind.
Fortunately, hagfish have a pineal eye.
This third eye is a sensory structure capable of light reception.
Systems Hagfish have both a nervous and a circulatory system.
Nervous System
The hagfish central nervous system consists of a brain and eyes.
Because they are Chordates, they also have a notochord and a dorsal tubular nerve cord.
Hagfish have cranial nerves, which are the antennae sticking out of the head, which sense sound and vibration.
The tentacles on their mouth are also for sensory purposes.
Hagfish have three or four pairs of barbels around their mouth, and on their nose, that sense odors.
Circulatory System
Hagfish have a closed circulatory system, meaning blood flows through vessels.
Their heart has two chambers, an atrium and a ventricle, and the path has two loops.
Blood flows from the gills, to the body, to the heart, and back to the gills.
The oxygen in the blood is used, and the carbon dioxide is excreted.
Interesting Facts
- Hagfish are eaten in Korea
- They eat through the nets of fishermen to get to the dead fish
- Their skin is used to make purses, wallets, handbags, and... boots
- As a defense mechanism, they secrete white slime all over themselves
- They then tie themselves in a knot to get sll the slime off
- They "sneeze" to get any slime that is clogged in their nostrils out
- In the future, the slime might be used as a substitute for eggwhites
- Hagfish can be from pink to grayish blue
References
- Prentice Hall Science Explorer- " Animals " by Jan Jenner Ph. D Publisher- Pearson Education, Inc.
- " Laboratory and Field Investigations in Marine Life " by James L. Sumich Publisher Jones and Bennet
- http://britannica.com
- http://school.eb.com
- http://web.ukonline.co.uk
- http://gma.org/fogm/myxine_glutinosa.htm
Pictures!
![[1]](http://4.bp.blogspot.com/_PNxeCWocPSs/St8x331_zMI/AAAAAAAABK8/Dc5V_8_Jq3g/s200/Hagfish2.jpg){kind=link}
![[2]](http://www.doc.govt.nz/upload/58351/hagfish-223.jpg){kind=link}
