||There are many fish
in the sea, but none are quite as intriguing as the Tetraodontidae or Puffer
Fish. This fish lives in the shallow waters of warm tropical areas. The
puffer inhabits the warm waters around China, Japan, Taiwan and the Philippines.
The body of a Puffer is exactly what one would expect. They are cone-like
structures with the widest end being the head, and the posterior tapering
to the tail fin. When the Puffer feels that he is being threatened, the
fish has the ability to inflate its body. The
inflation consists of a swelling of the body by taking in air and water.
While doing this the fish will float upside down until it can release the
air. By swelling the puffer becomes too large to consume. Some Puffers
also have small spines (Photo by ScubaMom).
Puffers have strong jaws and teeth fused into
a parrot-like beak used to crunch open the shells of the crustaceans, molluscs
and echinoderms that they feed on.
Another defense which makes the Puffer not
an ideal choice is that the flesh of the puffer is suffused with
Tetrodotoxin is a powerful neurotoxin that can cause death in nearly 60%
of the humans that ingest it. A human only has to ingest a few milligrams
for a fatal reaction to the toxin to occur. Once consumed the toxin blocks
the sodium channels in the nervous tissues, ultimately paralyzing the muscle
tissue. Curiously, the toxin seems not to be synthesized by the fish itself,
but by bacteria associated with the fish! The fish has a mutation in its
own sodium channels which makes it resistant to the effect of the toxin.
FUGU GENOME PROJECT?
Recently the Puffer Fish has been discovered by geneticists interested
in comparative genomics -- the study of how genes are organized in different
species. Many fish have genomes even larger than the human genome of 3
billion nucleotide pairs, but puffers were found to be at the low end of
the vertebrate scale, with only about half a billion nucleotides. Although
the number of working genes seems to be similar in Puffers and in Mammals,
Puffer genomes seem to have less "filler" DNA , and may represent a minimal
set of genes needed to make a vertebrate.
The Puffer Fish
|Symptoms of the fatal poisoning
are extremely obvious. First the person may vomit, have light-headedness,
dizziness, feelings of doom, and extreme weakness. And these symptoms are
for the MILD cases. More extreme reactions may include hypertension, bradycardia,
depressed corneal reflexes and fixed dilated pupils. The Puffer claims
70-100 lives each year due to improperly prepared fish.
Although the Puffer is commonly known to be
a deadly food, thousands consider it to be a delicacy. The common parts
of the fish that are eaten are the liver, gonads and skin. Specially trained
chefs may prepared the food so that it can be safely consumed. It is illegal
for anyone else to prepare the fish. Most people who are poisoned have
illegally smuggled the fish into the United States. The fish can only be
sent to certified fugu chefs. The risk of eating the fish is almost as
high as the price of actually purchasing it. In Japan, it costs the equivalent
of up to $150 for a single fish. Americans may pay up to $400 to find a
single legal meal.