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Something Big

sharkman6224 at my-deja.com sharkman6224 at my-deja.com
Fri Jan 14 04:29:32 EST 2000



>>Zvonka.Murko at guest.arnes.si wrote:
>>(recorded recently) where the scientists put some bait on a net on the
>>ground (I think very deep) to lure some deep sea sharks.

This is becomming more frequent, especially by Prof. Clark of Maryland
University and Mr. Kristof of the National Geographic.   The scientists
decend (either in a mini-submersible or use a remote camera) to about
3600m (12000ft)!

>>First came some normal specimens (I do not know which species)

The usual selachian visitors to these baited stations include Gulper
Sharks (_Centrophorous_ spp.) and Gummy Sharks (_Mustelus_ spp.).   That
said, there is a record of a female Tiger Shark (_Galeocerdo cuvieri_)
at 300m (1000ft) at Grand Cayman!

>>They said that it was a newly discovered species of shark, not
>>mentioning its scientific name.   In german they named it Schlaff Hai
>>meaning in english Sleep of Sleeping Shark.

It's not *really* a new species (i.e post-1984, when the first major
synopsis of sharks was published).   The shark in question is a Pacific
Sleeper Shark (_Somniosus pacificus_), a relation of the Greenland Shark
(_S. microcephalus_) and Little Sleeper Shark (_S. rostratus_).
_Somniosus pacificus_ is the most recently discovered Sleeper Shark,
with the first reference being from Bigelow & Schroeder in 1944!

Classification wise, the afforementioned sharks are amongst about 16
members of the family Somniosidae, which inturn is part of the order
Squaliformes (Compagno, 1999).   The Sleeper Sharks are 5-gilled
species.

The largest specimen encountered to date was a female filmed at 1200m
(4000ft) in Japan's Suruga Bay, and was estimated at 7. (23ft)!
Indeed, the Pacific Sleeper is usually encountereed in the North
Pacific, although there are some records from the south.

Not a vast amount is known about their biology, although they are
thought to reach an average size of 5m (16ft).   They have small eyes,
two small spineless dorsal fins and (as with the Greenland Shark) toxic
flesh, presumably due to the high Trimethylamine content.   These sharks
 are generally sluggish, although they are known to feed on fish, seals,
octopus and demersal shellfish.   They are live bearers (ovoviviparous)
and may hold upto 300 eggs!

>>if possibly where could I obtain that underwater photage

The footage was most likely filmed by the National Geographic Society
(www.nationalgeographic.com).   Further information about deepsea sharks
can be found in issues of the National Geographic (inc. 170(5):681-91.
1986) and:

Clark, E. * Kristof, E. (1991). How Deep do Sharks go? in: Gruber, S.H.
(Ed.) (1991). Discovering Sharks. Amer. Littor. Soc. p.79-84.

Multiple Contributors (1994) Sharks: Silent hunters of the deep.
Reader's Digest, London.

Bannister, K. (1996) The Book of the Shark. Grange Books, London.

There are some papers on Sleeper Sharks specifically but I'm afraid I
don't have the references to hand.

>>I think that in some way this (if true) also leaves the question of
>>the existence of the Meglodome Shark a bit if not wide open.

My personal opinion (for various reasons) is that the Megalodon Shark
(i.e. _Carcharocles megalodon_) doesn't exist today!   The principle
reason for this is that these sharks were found in biologically-rich,
warm coastal waters where their large prey (whales) were relatively
abundant.   Fossil evidence shows that they didn't skulk mysteriously in
very deep water.

Anyway, I hope that went some way to answering your questions & that you
found it of some interest.   If you have any further questions please
feel free to contact me.

                    Cheers,
                              -- M.B.


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