Ocean
Watch
Monday, November 16, 1998
Slimy, blind hagfish
work to keep
ocean floor clean
YEARS ago, when I first moved to Hawaii, I was obsessed
with reef fish. I wanted to know everything about these otherworldly
creatures - their names, what they eat, how they reproduce . . . there was
no end to the questions I had about Hawaii's marvelous marine fish.
I bought some popular fish books, but they weren't
enough. Soon I enrolled in an ichthyology course at the University of
Hawaii.
It was my first class there and I couldn't wait to
begin. I looked forward to learning some serious local marine biology.
Imagine my disappointment when the professor started
the semester by teaching about one of his personal favorites, the hagfish.
For those who never heard of hagfish, here's a clue to
my dismay: These fishes' other common name is slime hag and their
scientific name means mucus.
The names are appropriate because hagfish are masters
at creating slime. One adult can turn a two-gallon bucket of water into a
thick, gooey gob in just minutes.
Hagfish make this slime with about 200 specialized
glands, releasing the stuff in varying amounts, depending upon the
circumstances.
When feeding, hagfish produce only a small amount of
slime. But when cornered or captured, the fish oozes from all glands at
once.
Hagfish slime begins as a small amount of thick white
fluid. But the strange excretion absorbs seawater and thus expands several
hundred times in size.
The resulting clear goo clogs up the gills of fish
predators, either suffocating them or driving them off.
The system works well, except for one minor flaw: The
hagfish hates its own slime.
But this is no real problem for a hagfish. To get rid
of its own gunk, this 3-foot-long, eel-shaped fish simply ties itself in a
knot, then sweeps the knot toward the head, scraping itself clean.
Besides their slime and knot-tying habits, hagfish are
also odd in that they are blind, jawless, scaleless and finless. In 1758,
a biologist even classified them as worms.
So, what good are these outlandish fish? Slime hags are
an asset to the ocean, playing a crucial role in the marine food chain.
These fish live on the ocean floor, eating just about
anything they come across, dead or alive. That means they clean up the
messes, vacuuming up everything from dead whales to the discarded
so-called "bycatch" from commercial trawling fleets.
They are also important food for some octopuses,
seabirds, fish, seals and dolphins.
Since hagfish don't have teeth, they can't bite through
tough whale skin or fish scales. Unless other scavengers have already
opened a carcass, hagfish enter through the gills, mouth or anus, then eat
from the inside out.
Although hagfish live in Hawaii waters, few of us are
likely to ever see one. These fish prefer water cooler than 71 degrees
Fahrenheit and therefore stay deep.
In tropical waters, hagfish are usually found at about
1,800 feet or deeper. In the cold waters of South Africa, Chile and New
Zealand, hagfish are sometimes seen in tide pools.
Most of us can't get to the southern hemisphere to see
a hagfish, but we can try looking at Ala Moana Shopping Center. The
purses, shoes and wallets advertised as eelskin are often made of
slime-hag hide.
Like countless other marine fish today, hagfish
populations are being drastically reduced as fishermen take them for their
skins. No one knows the ultimate result of the decline of this strange and
wonderful fish, but likely it isn't good.
Today, I thank my former professor for teaching me about hagfish and
dozens of other fish unknown to me.
I know now that that's the real reason I was there.
