Moira:
>Which [fish] are the most toxic, have the most mercury?

It's a pretty grim story (which goes way beyond mercury) and one I looked
into since I eat my seafood raw and usually "ripe". In general I approach
it this way....

I never consume farmed fish. These fish are penned their whole life and fed
the equivilent of Purina fish chow--along with an increasing nummber of
medications to try and deal with the diseases inherent in overcrowded
poorly-nourished conditions. And they taste funny to boot. Unfortunately,
most of the salmon in markets is farmed--but wild salmon is avavailable if
you look hard enough, especially during the summer and fall. Other commonly
farmed fish include striped bass, catfish, and trout.

I usually avoid freshwater fish unless I can find ones from _remote_ areas.
Freshwater pollution levels are usually higher than the deep ocean levels.
Fish from the Great Lakes is particularly toxic.

In general, a fish which feeds mostly in the deep ocean is better than
those who feed along polluted shores. Tuna are a classic open ocean fish.
Wild salmon also spend most of their life in the open ocean. Alaskan
halibut is pretty clean. Ling cod, however, are shore-dwellers.

The most troubling part about pollution is that most researchers agree that
the bioaccumulation of toxins is greater in fatty fish, that it is in the
fat (and organs, esp the liver) that toxins accumulate the most. Also fish
lower on the food chain will theoretically have fewer toxins than those
fish who eat fish who eat fish. Since I am eating fish for the fat I assume
that the benefits still outweigh the detriments. Wild salmon, mackeral in
the fatty season (fall and winter), and fresh sardines or herring (_very_
hard to find) are among the best fish for fish oils by analysis. Among them
the sardines and herring are lower on the food chain. Mullet is nice (great
roe) as well. There is also an interesting new fish (quite large) which is
caught near Antarctica, often marketed as "Chilean ice fish" which is
_extremely_ fatty and white-fleshed--an unusual combo. The texture is very
very firm. I have never seen a lipid profile on it but I think it is a
pretty safe bet that it has all the right stuff. And maybe less
bioaccumulation considering it comes from the cold waters of the extreme
south.

There are so many different kinds of tuna, and the flavor varies so much
with season and location (and it simply doesn't compare to the other fish I
mentioned for taste IMO) that I can't say much about tuna--except that it
is often cited as one of the "top-of-the-food-chain" toxin accumulators. On
the other hand it is a deep-ocean fish, as well as one commonly eaten raw
as sashimi--the falvor of raw tuna is entirely different than canned
(cooked) tuna.

You didn't ask, but regarding shellfish, I find the oysters from Washington
to be generally less polluted tasting than east coast oysters (though Maine
has some nice ones) or the Gulf oysters. The larger sea scallops (as big as
a small potato in some cases) are preferable to bay scallops (small) since
the large ones come from much farther out (and also usually from relatively
cleaner Alaskan waters). Mussels are known to accumulate lots of crap so
making sure they come from clean waters is probably important. Clams? Same
comments as oysters.

Cheers,
Kirt


Secola  /\  Nieft
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