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MARINE LEECH
1 Trachelobdella lubrica ?
Sharon
Williams found this animal at the dive site called Manta Ray Bay,
near Honokohau Harbor on the Kona coast of the Big Island. Dick
Lundholm took these photos. Dick reports that it was about 1 to
1 1/2 inches long and was curling and uncurling, extending itself
and contracting.
Leeches
are a type of segmented worm in the Phylum Annelida. (Bristle worms,
fireworms, Christmas tree worms, spaghetti worms, and earthworms
all belong in this group.) Leeches are distinct in that they have
a sucker at each end of the body. Most but not all are blood-suckers
which attach to other animals. This one was probably waiting for
a fish to swim by. Sharks in Hawaii often bear other species of
leeches on the gills or fins.
Leeches live in fresh water, in salt
water, and on land. At least 160 species are marine, most of which
occur in polar seas, or in cold temperate waters. At least 3 are
known so far from Hawai`i.
I
sent the photos to Dr Eugene M. Burreson of the Virginia Institute
of Marine Science, who replied: "The
large bulges on the side are called pulsatile vesicles. My guess
is that it is Trachelobdella lubrica, a leech that is fairly
common on the gills of tropical marine fishes (non-elasmobranchs),
and known from Hawaii. T. lubrica has large pulsatile vesicles
like the ones in the picture. I have examined specimens of it in
the Bishop Museum. There are few good photos of marine leeches in
their natural habitat, so it was a pleasure to see this one.
Pauline
Fiene adds "We have seen a different species on whitetips and
they move just like that."
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