7775

• UCREFRP Catalog Number: 7775
• Author: Carlson, C. A. and R. T. Muth.
• Title: Inland Fisheries Management in North America, Chapter 15
• USFW Year: 1993.
• USFW - Doc Type: Endangered Species Management.
• Copyright Material: YES

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Chapter 15

Endangered Species
Management

CLARENCE A. CARLSON AND ROBERT T. MUTH

15.1 INTRODUCTION

Several nontechnical accounts of declining fish faunas and fisheries have been
published (e.g., Brown 1982; Mowat 1984; Warner 1984; Ashworth 1986).
Recurrent themes run through these stories; species of value to humankind were
overexploited, "worthless" species were destroyed for the presumed good of
other commercially valuable species, and various human activities (e.g., damming
rivers, polluting water and air, and introducing nonnative species) led to depletion
of other species. Many more tales of fish or fisheries depletions that are likely to
be read by nonbiologists could be mentioned. Accurate reports like these are
important; their examples of biotic declines and extirpations conform to a general
trend that is Dot limited to North American fishes, and they help to increase public
awareness of serious environmental problems. The ultimate decline, that which
culminates in extinction, may be occurring worldwide at an unprecedented rate
and in many forms of life as a result of human actions.

15.1.1 Accelerated Extinction

Extinction usually occurs when populations are unable to persist as their
environments change. Extinction may be local, when a given population fails, or
global, when an entire species is eliminated. Extinction is a normal process, and
global extinction has been the fate of most species produced during the Earth's
history (Ehrlich and Ehrlich 1981). Estimates of the rate of species loss have been
made in spite of difficulties inherent in such estimation and lack of data on biotic
diversity. Myers (l979a, 1979b) estimated that at least 90% of all species that ever
existed have become extinct, mostly as a result of natural processes. By 1600,
humans became capable of driving animals to extinction. The human-induced
extinction rate increased to about one species per year and held relatively
constant from 1600 to 1900. It increased again to perhaps one species per day by
1979 as humans exploited ecologically diverse moist tropical forests. Myers (1985)
expected humans to accelerate the extinction rate to one species per hour by the
late 19808 and to dozens per hour by the end of the 1990s. He compared these
rates to the maximum rate of extinction of the dinosaurs (one species every 10,000
years) to emphasize his point that there has never been such a period of massive

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