 Ocean
Watch
Friday, May 09, 2003
Check the water
before digging clams
A reader recently wrote me that in the 1940s people dug
for clams in the Ala Wai Canal. It's not safe to eat anything caught in
that polluted waterway anymore, but he wondered about other places.
"I bet there are pristine locations on the neighbor
islands where clams can be harvested. Those who know probably don't want
to share this information."
The clams of which my reader writes are not native to
Hawaii. In the 1920s several species of clams and oysters were introduced
from Japan and North America to Hawaiian waters as a food source. Among
these was the Japanese littleneck clam, also known as the Manila clam.
Gathering these clams on the mud flats of Kaneohe Bay
was a popular activity until 1969, when silt and overharvesting mostly
wiped out the beds. Today some of those introduced edible species still
live in sheltered, shallow areas such as Pearl Harbor, Maunalua Bay and
Kaneohe Bay. If they thrive and are harvested anywhere else in Hawaii, I
don't know where.
Clams, whether native or imported, are scarce in
Hawaii, but in other parts of the world, they're practically a lifestyle.
In New England, people hold parties called clambakes during which they
steam clams, lobsters, corn on the cob and potatoes over coals in large
pits.
The Pacific Northwest's beaches often are littered with
clamshells, and you can get steamed clams just about anywhere on the West
Coast. One of my favorite Seattle restaurants has a sign at the entryway
that says, "KEEP CLAM."
In the biology world, clams are part of a large class
of animals called bivalves. These animals, which include mussels, oysters,
scallops and other lesser-known types, all have two hinged shells that
usually enclose the animal's entire body.
The most famous clams in the world are the giant clams
of the Indo-Pacific. But not all giant clams are big. Six species fall
into this category, the smallest being only about 4 inches across. The
largest, however, lives up to its name. It can grow to more than 4 feet
wide and weigh around 700 pounds.
Giant clams grow hinge down, with their two shells
gaping open. Contrary to the scary stories, giant clams do not clamp onto
swimmers and divers and hang on. If startled, the clam will partially
close its shells, but it can't close them completely.
All bivalves have a muscular foot. In some species the
foot is efficient at digging, allowing the creature to burrow deep into
sand or mud. The foot is also the part of clams and other bivalves that
people like to eat, although we swallow the animals' guts, gills and
gonads right along with the feet.
People who grew up eating clams think they're the food
of the gods. Others of us, however, never quite warm up to the idea of
steaming an animal alive and then eating it, guts and all, often including
grains of sand.
Clams and their cousins are filter feeders, meaning
they sift food from the surrounding water. During this feeding they can
collect pathogens such as those that cause red tide, hepatitis and other
diseases. Clean water, therefore, is crucial when it comes to harvesting
clams.
I don't expect anyone to divulge their secret clamming
spots to me. But if anyone is clamming in Hawaii today, please make sure
the location is pristine.
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