7040

• UCREFRP Catalog Number: 7040
• Author: Miller, R. R.
• Title: Man and the Changing Fish Fauna of the American Southwest
• USFW Year: 1961
• USFW - Doc Type: Papers of the Michigan Academy of Science, Arts, and Letters
• Copyright Material: YES

W

m
d
i
i
i
i

366 Robert Rush Miller
• i ,AGl? a ? ?•??? XIC ? ._
lp Mlw
J/",J) Syr
? ar Imo - t
Fla. 1. Drainage map of Southwestern North America, showing localities men-
tioned in the text.
endemism (Miller, 1959). Many of the species have limited ranges,
and some are even confined to habitats that contain only a few
thousand gallons of water or cover scarcely an acre. Presumably as a
result of greatly reduced competition and little pressure from preda-
tion, these isolated populations lack the defense mechanisms that are
developed in more nearly saturated faunas, and hence they have been
rather easy prey for the typically more aggressive exotic species.
It is the purpose of this contribution to describe some of the en-
vironmental modifications that have occurred in the Southwest, to
document where possible the changing nature of the fish fauna, and
to present evidence that modern man has been the chief architect of
these changes.
{

-
ti