<< A factor with bull sharks (aka the Zambezi shark in southern Africa)
into freshwater is that the water must be fairly warm. They have been
recorded in the likes of the Ganges, Mekong, and Amazon as far inland as
Manaus. I think they are also the so-called freshwater shark of the
Mesoamerican lakes (Managua, Nicaragua ....)
The Thomerson article (it has been quite a while since reading it) may have
raised the question as to whether they would be caught again in the
Mississippi as far north as Illinois. Would the water below the dams be too
cold (rather below 80 degrees F.) for them? >>
That is a factor which I hadn't been previously aware of; that the water had
to be so warm. This explains why bull sharks are cited as being infrequent
visitors to North American freshwaters. Thanks.
They are the freshwater sharks of Lake Nicaragua (never knew about them in
Managua.) They were isolated there a long time ago (I think due to volcanic
activity) and adapted to the environment. There are also freshwater sawfish
present in the lake.
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