7374

• UCREFRP Catalog Number: 7374
• Author: Sheldon, A. L.
• Title: Conservation of Stream Fishes
• USFW Year: 1988
• USFW - Doc Type: Patterns of Diversity, Rarity, and Risk
• Copyright Material: YES

Conservation of Stream Fishes:
Patterns of Diversity, Rarity, and Risk

Zoology Department
University of Montana
Missoula, MT 59812, U.S.A.

Abstract: North America has a rich fauna of freshwater
fishes which attains greatest diversity in the central and
soutbeastern United States. Many stream fishes have limited
ranges and are locally rare and patchily distributed Local
diversity increases downstream and total diversity follows
tyPical species-area relationships. Drainages linked with the
large Mississippi system support more species than those of
comparable area flowing directly to the sea, and rivers iso-
lated by falls have notably few species. The between-
drainage component of diversity is large. 1'I1fwIfs tti this,
JiIlInr4 which lire not addressed by management focused on
threatened species, Include ft'ttg",:mmtlo1t. tJfilmhft!t[(e ne"
~by~tmd~onoffaunasby
atM... <<l,,"~ fItItI iDIrodllCtiofll&. Cor.servation ef-
forts require a biogeographic perspective; they should focus
on streams of intermediate size (orders 4-6) plus the up-
stream portion of each drainage and should attempt to
maintain total diversity and, inclusively, populations of
rare or threatened species.

The rivers and lakes of North America are inhabited by
a rich assemblage of fishes_ Approximately 700 species
regularly spend all or significant portions of their life
histories in the fresh waters of the United States and
Canada (Lee et al. 1980); the diversity exceeds that of
the birds of the same region (Robbins, Bruun, & Zim
1966). The distinctive Mexican fauna (Miller 1966;
Miller & Smith 1986), with numerous endemics and an
infusion of neotropical taxa, adds many more. Although
.me diversity of fishes in the United States does not ap-

Resumen: A~er;Ciidel None tiene una fauna rica en peces
de agua dulce, la cual alcanza su mayor diversidad en /as
regiones central y sureste de los Estados Unidos. Muchos de
los peces de arroyos tienen una extenci6n limitada, son raros
a nivellocal y se encuentran irregularmente distribuidos. La
diversidad a nivel local aumenta aguas abajo, y la diver-
sidad total sigue las relaciones t{picas de especies-area. La.<;
cuencas conectadas con el gran sistema del rio Mississippi
contienen mils especies que aquel/as de superficie compara-
ble que desembocan directamente al mar, y los rios aislados
por cataratas presentan un numero de especies notable-
mente peque60. El componente de la diversidad de /as espe-
cies que se encuentran en /as areas entre drenajes, es grande.
Las amenazas a eSta fauna, problema no tratado par el
manejo enfocado en especies en peligro de extincion, in-
cluyen la fragmentaci6n de /as redes de drenaje por medio de
represas y la homogenizaci6n de faunas mediante conec-
ciones entre cuencas e introducciones. Los esfuerzos de con-
servacion requieren de una perspectiva biogeografica, deben
enfocarse en arroyos de tamaiio intermedio (orden de 4-6)
mils Ie parcion aguas arriba de coda drenaje, y deberian
intentar mantener la diversidad total e, incluso, las pobla-
ciones de especies raras 0 en peligro de extincion.

proach that of the great tropical rivers of South America,
Africa, and Asia, it far exceeds that of European fresh
waters (Lowe-McConnell 1969, 1975).
Freshwater fishes of the United States include survi-
vors of ancient lineages such as the bowfin (Amiidae),
gars (Lepisosteidae), sturgeons (Acipenseridae), paddle-
fish (Polyodontidae), and mooneyes (Hiodontidae).
Many families (e.g., minnows, Cyprinidae) are shared
with Eurasia, and in some families, including the pikes
(Esocidae) and sculpins (Cottidae), geneQ or species
occur throughout the Holarctic. Sunfishes (Ccn-
trarchidae~, and a catfish family (Ictaluridae) are re-

149

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Conservation Biology