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

as a last resort for managing threatened and endangered
fish populations.
Conservation aquaculture is simply what the term
implies-use of aquaculture for conservation and recovery
of endangered fish populations. The term does not em-
brace standard hatchery practices used as a past baseline
of evaluation. Conservation aquaculture involves working
adaptively with the local gene pool and allowing sufficient
migration of genes to allow allelic representation. It re-
quires careful selective breeding programs to provide suffi-
cient diversity within a fish population of interest. It
necessitates eliminating as much artificial conditioning as
possible. When successful, it provides the increased popu-
lation base on which natural selection can operate. As a
result of its design, conservation aquaculture can reduce
the commonly considered risks associated with hatchery
production such as competitive feeding behaviors, re-
duced growth rates, domestication selection, and increased
incidence of disease. Finally, conservation aquaculture by
no means presents the same risks associated with letting
nature take its course when nature is no longer able to sus-
tain a wild, native fish population.
Perhaps more than a specific set of culture techniques,
conservation aquaculture is an adaptive, creative approach
that prioritizes preservation of wild populations along
with their locally adapted gene pools and characteristic
phenotypes and behaviors. Thus, the conservation aqua-
culture approach directly contrasts the ideology underly-
ing more-traditional hatchery supplementation programs,
in which success was largely a function of total numbers
of fish released from a hatchery. Conservation aquaculture
should be viewed as one component of multifaceted fish
restoration and recovery programs, many of which
include important habitat improvements. Some supple-
mentation programs have treated the symptom of declin-
ing fish populations in lieu of addressing serious issues of
degraded and lost fish habitat or other causal factors. In
contrast, conservation aquaculture is designed to be imple-
mented simultaneously with habitat improvement and
watershed or ecosystem restoration activities. Conversely,
the goal of
many tradition-
al hatchery sup-
plementation
programs has
been to crea te a
harvestable sur-
plus of fish. The
goal of conser-
vation aquacul-
ture is to con-
serve wild fish
populations
along with their
locally adapted
gene pools and
characteristic
phenotypes and

I
t

November 1998

behaviors. The importance of this distinction between
approaches cannot be overemphasized. The fact that con-
servation aquaculture is not concerned with producing
record numbers of fish for release alleviates many stress-
mediated problems associated with high-density fish rear-
ing. In addition, due to the complementary nature of con-
servation aquaculture, commonly raised concerns that fish
hatcheries "divert attention away from the real problems"
or somehow usurp the need to address causal factors of
fish population declines do not apply to conservation
aquaculture.
Concerns and risks associated with aquaculture,
including inbreeding fitness depression, domestication
selection, manifestation of disease, hybridization, and
introgression are often readily observable and have been
well documented (Allendorf and Ryman 1987; Waples
1991). However, such observations may result from what
Brannon (1993) referred to as "the perpetual oversight of
hatchery programs" rather than from aquaculture per se.
That is, when hatchery programs ignore the fact that fish
populations are both the product of and an integral part
of a complex ecosystem, their success is jeopardized.
Brannon (1993) further suggested that if hatchery pro-
grams neglect the requirements of natural populations
and, therefore, the traits they possess that allow them to
synchronize their life history with specific environmental
constraints, failure is certain.
Several views have been offered regarding the appro-
priateness of various conservation and management
strategies for endangered species (Flagg et al. 1991). One
approach relies primarily on habitat improvement for
recovery of endangered fish populations, after which pop-
ulations should be left to rebound naturally. However, if a
significant portion of the gene pool or important locally
adapted genes are lost, the endangered fish population
becomes permanently modified, and no amount of habitat _
protection or alteration can restore it. Conversely, if habitat 7
needed to support an endangered population is una vail- "
able or of poor quality, potential benefits of a conservation 1
aquaculture program could be limited due to insufficient )

Ef{~ttive
Getletic ........ ..,}ii< ...........
within-popu.lation....ge!,'\.~~c;AI<!rjatjoo
Wrthin-population~eo.~',f1oW
Inter-pop~lational g~oe.flow.
Inbre~di~~.gepres~i~I'l.<.. .
Rec;ruitm~~lto age-I.'. <..
Pc;lP4Iatio~.viabi'ity
Probability of populat!()n peisistenc;e .
Extinction risk
Probability of succes5fuLcon~rvatibn
aquaculture

Fisheries. 29