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But a diver has to
look hard to spot this master of disguise. Its camouflage
allows the oyster toadfish to blend in perfectly
with its surroundings, waiting for a meal of small
fish or crustaceans to swim by its big mouth. This
habit of not working hard for its living has earned
it a reputation as a lazy fish by some scientists
who have studied it.
Some researchers say the toadfish is a fish with
an attitude – it’s been called belligerent,
ill-tempered and aggressive. The toadfish’s
name, and perhaps part of its reputation, comes
from the grunting sounds it makes when it is caught.
The male fish also makes the sound during spawning
season -- possibly as a way to protect the nest
of eggs it guards during the incubation period.
While it may sound like a truly disagreeable fish,
Opsanus tau is actually very important to
humans. The oyster toadfish has been used in studies
of insulin and diabetes, drug metabolism, hearing,
dizziness and motion sickness. In fact, two oyster
toadfish were along for the ride when John Glenn
made his famous return to space aboard the space
shuttle last year. The fish were part of a
continuing study to help scientists better understand
the mechanisms that control our sense of balance.
There is one species of toadfish whose name sets
it apart from its motley kin -- Sanopus splendidus,
the splendid toadfish. Indeed, its striking, colorful
appearance presents quite a contrast to the other
members of the toadfish family. Found only on the
reefs around Cozumel, Mexico, the splendid toadfish
has a zebra-striped head and is accented with wide,
yellow borders on almost all of its fins. Its ventral
fin, located on the fish’s underside closest
to its head, is entirely yellow.
Opsanus tau and the Atlantic midshipman
(Porichthys plectrodon), which is a member
of the toadfish family, are common to the North
Carolina coast. The midshipman gets its name from
the 600 or so button-like light organs that are
arranged in rows along its body – like a midshipman’s
coat!
The frogfish has a different shape than the toadfish
and you might say it is a little more proactive
in the way it hunts for food. The frogfish is round
with a mouth that resembles a trapdoor. Above that
trapdoor is a dorsal spine that, when wriggled over
the mouth, acts as a fishing lure for small fish
and crustaceans. The frogfish’s mouth can expand
to 12 times its normal size in about eight milliseconds,
enabling it to quickly gobble up prey mesmerized
by the lure. Talk about fast food!
Frogfish species come in many different colors,
including black and yellow. Like the toadfish, it
is able to camouflage itself and blend in with its
habitat. Some frogfish may look like sponges, complete
with patterns in the skin that resemble the holes
found in sponges. Others may look like clumps of
seaweed or seaweed-covered rocks. In addition to
its coloring, the frogfish’s gill openings
are hidden behind its pectoral or side fins. That
way, prey is not tipped off to its presence by outflowing
water from the frogfish’s gills.
Three species of frogfish can be found off the
North Carolina coast: the ocellated frogfish (Antennarius
ocellatus); the singlespot frogfish (Antennarius
radiosus); and the splitlure frogfish (Antennarius
scaber). They range in size from three to 15
inches and can be found along the bottom in shallow
waters.
Additional Resources
Marine
Biological Laboratory, Woods Hole
Waikiki
Aquarium: Marine Life Profile - Frogfish
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