9427

• UCREFRP Catalog Number: 9427
• Author: Anders, P. J.
• Title: Conservation Aquaculture and Endangered Species
• USFW Year: 1998
• USFW - Doc Type: Can Objective Science prevail over Risk Anxiety?
• Copyright Material: YES

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FISHERIES MANAGEMENT-PERSPECTIVE

Conservation Aquaculture and
Endangered Species:

Can Objective Science Prevail over Risk Anxiety?

By Paul J. Anders

quaculture has been used with varying degrees
of success to conserve endangered fish popula-
tions, and its use continues to be a controversial
recovery issue in fisheries. Fisheries manage-
ment decisions involving the design, implementation, and
evaluation of conservation aquaculture programs can be
complex and difficult. Such decisions often must be made
in the midst of considerable uncertainty. In fact, one of the
tenets of conservation biology states that in a crisis, as is
usually the situation with endangered species manage-
ment, one often must act before knowing all the facts
(Soule 1985). This notion virtually guarantees some degree
of uncertainty in many management decisions. This is
especially true with threatened or endangered fish pop-
ulations because small population sizes confound data
collection and analysis necessary to develop scientifically
sound management policies. Furthermore, many public
and political groups as well as fisheries professionals
demand precise, rigorous definition of the uncertainties
associated with management decisions.
In some cases, a rift seems to exist between principles
of population biology and fish management policy regard-
ing the use of aquaculture to conserve endangered fish
populations. In particular, a management policy that con-
siders aquaculture as a "last resort" for conserving threat-
ened and endangered fish populations can be counter-
productive when it allows a population to dwindle to
near-extinction in order to "keep it wild." The objectives
of this article are (1) to discuss several basic tenets of
endangered species management from a populationbiolo-
gy perspective; (2) to define conservation aquaculture and
discuss its role in endangered species management; and
(3) to discuss the potential dangers of fisheries manage-
ment policies that consider aquaculture as a last resort for
conserving endangered fish populations.
Conservation and management strategies may be strong-
ly influenced by a number of problems associated with
small population size. Of considerable concern is that nat-
ural and artificial recovery options are rendered ineffective
when populations decline below a threshold size, which is
rarely defined. Thus, the key to successful management of
threatened and endangered populations must be to apply
appropriate conservation measures that minimize risk and

Paul J. Anders is a doctoral student in the Fish Genetics
Laboratory, University of Idaho, Aquaculture Research Insti-
tute, Moscow, 10 83844-2260; [e-mail]. He
serves on the Kootenai River White Sturgeon Recovery Team.

28 . Fisheries

maximize benefit before their potential for success is over-
ly compromised by small population size or reduced pop-
ulation viability. Although this conservation philosophy
may read nicely on paper, in the real world its successful
implementation is a complex and difficult task.
The important point here is that when fish populations
get too small, effective pop,1J.lation size (Ne) may become a
better predictor of recovery.. success than hypothesized
outcomes of available mam,l.gement strategies. (For the
purposes of this article, Ne is defined as the number of
reproducing individuals in a population in a given year).
Empirically, an extremely low Ne through time becomes an
accurate predictor of extinction (Lacy 1987). Populations

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Healthy juveniles from the wild, like this young white sturgeon
from the lower Snake River, Idaho, or from conservation aquacul-
ture programs contribute to production of broodstock and popu-
lation p~rsistence.

with low Ne values can suffer from reduced viability and
persistence through linked mechanisms of reduced gene
flow, genetic drift, reduced within-population genetic vari-
ation, and inbreeding fitness depression; these populations
ultimately may face high risks of extinction (Gilpin and
Soule 1986; Lande and Barrowclaw 1987). In such a case, it
is difficult to develop a fisheries management strategy that
facilitates population recovery. Thus, maintaining an ade-
quate Ne is necessary for natural population viability and
persistence mechanisms to function properly. When com-
paring characteristics of large and small populations
(Table 1), virtually all the listed population persistence
mechanisms suggest overwhelming ability for a large pop-
ulation to persist relative to a small one. This overwhelm- ~
ing superiority of large populations argues strongly against
fisheries management policies that consider aquaculture

Vol. 23, No. 11