It’s probably safe to say that Knoxville has not often been featured in National Geographic magazine, but a local business has been highlighted in two issues of that international publication. Photos of rare native fish propagated at Conservation Fisheries, Inc. grace the pages of the March 2015 and April 2010 issues. CFI has been in business for almost 30 years as a non-profit organization dedicated to the preservation of this region’s aquatic biodiversity using a three-prong approach.
First and foremost, they work to restore populations of fish eliminated by water pollution or habitat damage, largely by propagating and releasing native fish back to the wild. CFI was the first facility in the Southeast to propagate rare, non-game fish for recovery work. They also produce fish eggs and larvae for toxicity testing to develop water quality standards, and using fish raised in captivity for this purpose spares wild populations. A third side of the business is non-invasive monitoring of rare fish populations, primarily by snorkeling.
CFI co-founders Patrick Rakes and J. R. Shute met at the University of Tennessee in Knoxville as graduate students studying fish species that were imperiled by habitat loss, and after completing school they founded CFI to continue that work. They’ve maintained aquarium populations of at least 65 fish species over the years, and two dozen or more rare fish species are likely to be growing in the CFI hatchery at any given time. For most, the ultimate goal is to return them to their native habitat. Sometimes, as a last resort, they keep “ark” populations of fish that seem on the verge of extinction. A new undertaking is propagating fish as hosts for the larvae of rare mussel species that are being reintroduced in Tennessee River tributaries.
Rakes and Shute have a small but enthusiastic staff who divide their time between hatchery and field work. The species they raise in their Division Street hatchery are smallish, usually only a few inches long. The Spring Pygmy Sunfish, whose native habitat includes just a few springs in the Huntsville, Ala. area, is a mere few millimeters in length. Learning the dos and don’ts of rearing fish from cold water streams has been a decades-long process, but these guys clearly have “wet thumbs.”
Larval (baby) fish often need live food, so one room in the hatchery is devoted to raising brine shrimp, rotifers, water fleas, and tiny worms. It can take more time to care for the food populations than for the fish. Some species, such as the spotfin chub, require strong currents provided by pumps, and all require very clean, cold water. Over the years they’ve experimented with a variety of natural and man-made materials, such as terra cotta tiles, to discover the best and cheapest ways of mimicking the substrate suitable for the fish to lay their eggs. All of this has resulted in a growing set of written protocols that others can follow to propagate the same species in other hatcheries.
As daunting as all this attention to detail can seem, the level of effort to actually get these fish back into the wild can be even greater. The first step is to stay abreast of land-use changes that can improve, or degrade, the habitat quality of a particular stream segment. For example, the upper Tellico River became a much better fish habitat after a wastewater treatment plant was upgraded, a cannery closed, and off-road vehicles were banned from the North Carolina side of Cherokee National Forest. Then the biologists look for the best spots for reintroducing fish to the stream, places with suitable cover and spawning sites. Getting to the reintroduction points can be as challenging as walking several miles off-trail carrying a backpack loaded with bags of water and live fish.
This kind of work takes a lot of patience, including waiting five to 10 years typically to see positive results of a reintroduction. A number of visits to a stream, each involving hours of snorkeling in cold water, may be necessary before they see the reintroduced fish persisting and reproducing. Even then there is work to be done to maintain genetic diversity in the wild populations. Fish tissue samples are sent to geneticists who advise CFI on how many individual fish to move from one stream to another to avoid the genetic bottleneck of too much inbreeding.
Stream monitoring is sometimes a harrowing experience, such as the time the co-founders were surprised by a sudden, violent thunderstorm while observing a nocturnal catfish species at night. Other times it can be surreal, as when a beaver suddenly looms out of the darkness, silvery bubbles streaming across its face as it swims toward the diver’s light.
Shute and Rakes know that their quest to save rare fish species and maintain this region’s unusually high aquatic biodiversity depends on changing behaviors that can and have led to extinctions. They point to agriculture as the “number one killer of our streams” via sedimentation that muddies the water and smothers fish eggs. Urbanization can degrade or eliminate aquatic habitat.
Collecting rocks from streams for landscaping materials removes the clean crevices in which most of these species must lay their eggs. Until these and other assaults on our waterways are stemmed, CFI will continue to buy time for these species and advance the art and science of native fish propagation. They hope the National Geographic exposure and a documentary that’s in the works will raise awareness of these beautiful creatures most of us will never see.
Patrice Cole's Small Planet educates readers on local issues pertaining to environmental quality and sustainability. Topics include particular threats to natural resources, public policy with local impacts, and advances in environmental science. She has 25 years of professional experience in environmental science and sustainability. She has also taught biology, ecology, environmental planning, and sustainability at the University of Tennessee and Pellissippi State Community College. Cole earned a master’s degree in planning and a Ph.D. in ecology and evolutionary biology at UT.
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