Saving Rare Fishes with Captive Breeding

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[edit] Saving Rare Fishes with Captive Breeding

John Tullock is a marine zoologist and author.
John Tullock is a marine zoologist and author.

By John Tullock
April 21, 2008

Too often, the aquarium hobby receives media attention as an economic engine helping to drive unsustainable harvest of wild fish populations. Nevertheless, aquarium technology, much of it developed for the hobbyist market, offers some of the best available tools for restoration of damaged aquatic habitats.

The idea of raising rare fish in captivity and releasing them into the wild has been thoroughly tested over the past 20 years in Tennessee by a little-known organization, Conservation Fisheries. This non-profit has succeeded in restoring three species of rare native fish that had been extirpated from Abrams Creek in the Great Smoky Mountains National Park. Studies have shown all three species are now reproducing in the creek, though years will be required for a complete recovery. Conservation Fisheries also works with about ten other rare fish from locations throughout the Southeast. From a small number of wild parents, thousands of baby fish are propagated each year and returned to their native streams.

[edit] Pisces in Peril

Every continent has numerous native fish species now threatened with extinction. The Nature Conservancy summarizes the bleak news on its web site:

Spotfin Chub: In serious decline but being propagated by Conservation Fisheries.

"Worldwide, most types of freshwater ecosystems generally are in grave condition and are declining at a much faster rate than terrestrial systems....More than 20 percent of the world’s known 10,000 freshwater fish species have become extinct or imperiled in recent decades.

"In the United States, 303 fish species, or 37 percent of the freshwater fish fauna, are at risk of extinction; 17 species have already gone extinct, mostly in this century."


Only the availability of funding limits the application of captive propagation techniques to a broader spectrum of aquatic species. When compared to other types of organisms, fish are often relatively cheap to produce. Less than half a million dollars per species has been spent over the past 20 years for the restoration in Abrams Creek mentioned above. Compare that to the millions expended on some other noteworthy species restoration efforts, such as the California condor.

Attrition rates for fish offspring in the wild are so high that hatchery production results in orders of magnitude increases in the number of surviving individuals. With birds and mammals in particular, such gains are almost impossible to achieve, due to the small number of offspring produced per pair. Captive propagation as a conservation tool probably makes more sense for fish than for any other animal group.

[edit] Aquarium Science's Future Role

Aquatic biodiversity conservation efforts focus mainly on habitat preservation. Protecting entire ecosystems from development or other human impacts is universally recognized as the best insurance against species loss. For many imperiled aquatic species, however, such protection may come too late. Captive propagation is neither the only, nor in some cases even the best, answer to the problem of declining aquatic biodiversity. However, aquaculture and aquarium science are likely to play an increasing role in conservation in coming years.

Aquarium propagation and maintenance of captive stocks of rare fish provide a way to protect irreplaceable species from extinction. Marine hobbyists who seek out captive-propagated fish support not only the fledgling ornamental marine aquaculture industry, but also the continued survival of the wild coral reefs that inspire us. Freshwater enthusiasts have had access to captive propagated fish for decades, but now the techniques pioneered by the industry are being successfully applied to problems of freshwater biodiversity worldwide.

Aquarium hobbyists both freshwater and marine now have the option to support sustainable practices that promote aquatic biodiversity. By purchasing captive-propagated fish, the hobbyist places no demand upon fragile wild populations, while continuing to enjoy a fascinating and educational hobby. I call that a win-win.

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John Tullock is a marine zoologist, author and consultant. His enormously popular Natural Reef Aquariums and numerous other books and articles, have focused upon the aquarium hobby and industry for two decades.