Re: [RML] it's amazing what you find in stores...

Scott Davis (unclescott at prodigy.net)
Wed, 2 Feb 2000 22:51:12 -0600

A number of years ago Jim Thomerson wrote a note to the Journal Copeia about
a shark being caught in the nets of professional fishermen in 1937 in the
Mississippi River near the Illinois town of Alton - a long ways up the
Mississippi. Thomerson didn't feel that such an incident would happen again
because of the flood control dams on the river since built. He suggested
that a certain water temperature (only seasonally that warm in the middle
Mississippi) was the limiting factor in terms of how far north they could
wander.

He also alluded to the Bull sharks (aka Zambezi sharks) swimming up the
Amazon at least as far a Manaus. I wonder if some of the stories of little
kids being carried away, attributed to a giant catfish - the salton, really
should be credited to bull sharks, listed on some web sites as having a very
cosmopolitan diet, inclined to "believe that the area that they happen to be
swimming in is their area..." and being perhaps the most dangerous of sharks
to people. They (and all sharks) seem to account for far fewer people than
do crocs. Carcharinus leucas has also been sighted in many of the African
rivers, the Ganges, Mekong, Tigris and has you guys have mentioned,
Australia, among other places.

The Lake Nicaragua shark shark seems now to be just to be a bull shark. (See
the cichlidroom at www.petsforum.com/cichlidroom/reviews/ro21.html) A search
will turn up a ton of sites on sharks, including a Shark L mailing list
where every now and then a plaintive request on how to unsubscribe will be
seen. Evidentally a rectal gland enables that fish to adjust its
osmoregulation from salt water to freshwater.

By the way,
http://www.flmnh.ufl.edu/fish/Organizations/SSG/9Newsletter/shark9news.htm
does speak of a Borneo freshwater shark, either the Glyphis species
previously found in a museum or a new species discovered by a group called
the IUCN. They recently went there and endured considerable rains looking
for them. They found them in fishermen's nets.

All the best,

Scott