Bluefin Tuna I can safely say that the bluefin tuna is perhaps the most
perfectly engineered animal in the ocean and possibly anywhere. It can
grow to be up to 1,500 pounds, migrate across the entire Atlantic, and
can attain speeds of up to 50 miles an hour. Living up to its name (tuna
means "to rush" in Greek), the bluefin tuna is built for speed and
endurance, with fins that retract into slots to add to an already
hdrodynamic profile, small finlets on the posterior part of the body which
reduce drag, and a countercurrent exchange system (called the rete
mirabile- "miraculous network") which allows them to maintain an warm
internal body temperature even in water that is near freezing. They can
cross the Atlantic in less than 50 days, and use the sun, electric fields,
scents, and currents to navigate. It's also the most
valuable and thus most over-exploited animals in the sea. Their dark red
flesh is highly valued. One
Atlantic bluefin tuna can be worth up to
11,250,000 yen ($90,000 U.S.). They
can live up to 40
years, but newly hatched bluefins have a 1 in 40 million chance of
reachind adulthood at age 8. Therefore, catching too many adult tuna
depletes the stocks relatively fast. The only way to stop the
depletion of these fish, which are endangered in some regions and will
definitely go extinct unless we do something, is to limit the market
on bluefins. This means strict quotas for fishermen. However, if
demand is less, the supply doesn't have to be as strained. It's ok to
eat tunafish from a can...that's usually albacore (it says so right on
the can, and as always get dolphin safe tuna), but tuna steaks sold in
restaurants may possibly be bluefin (although usually they're
yellowfin), and tuna in sushi may be bluefin. Just stay aware. While
I'm at it, there's other fish that are depleted. I've stopped eating
them...maybe you'll want to also. Check out the National Marine Fisheries Service webpage.
These people are the authority on sustainable catches and such. I
suggest you read it...it's pretty amazing how closely tied in this part
of marine biology is to politics and economics, two things I tend to
avoid. :P Another good page is the NMFS
Northeast Fisheries Science Center, which is a bit more
user-friendly, but focuses only on the Northeast.
(Thunnus thynnus)
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