Quality nutrition improves kelt survival.
Their words are like little urns. In them you'll find clues from the past that define the present in this plastic thing called "language." Some of the words are commonplace in usage, tame and mundane; they are overused and have no edge anymore, but are plain and smooth like creek stone.
Other terms are a little arcane and mysterious, at least to those who don't use them. One of the words Gannam is apt to use: kelt. Kelt refers to a moment in a fish's lilt. It is a word of Scottish origin that describes the languid state of steelhead and Atlantic salmon after they have spawned.
The experience is taxing, given that these migratory fish have fasted for months and have spent their energy stores getting to natal spawning habitats miles upriver from the sea. It is Pacific salmon that expire after they spawn for the one and only time in their life. Atlantic salmon and steelhead are multiple spawners, and one of the most taxing and critical points in their life histories is the time they linger in fresh waters, immediately post-spawn, when they are called kelts.
Atlantic salmon come upriver in May to July in advance of spawning in autumn, and they don't eat the entire time. They lose half of their body weight by winter. Nashua National Fish Hatchery in New Hampshire and the Richard Cronin National Salmon Station in Massachusetts collect Atlantic salmon and spawn them, and the spent adults--the kelts--make their way to North Attleboro National Fish Hatchery in Massachusetts for reconditioning.
Nutritionists know that a fit kelt is more likely to contribute additional offspring and promote the species' recovery. One way to promote their health is to use a specially formulated diet. Commercially available broodstock diets do not exactly meet the needs of kelts and are not palatable to them.
The Abernathy Fish Technology Center developed a hand-made fish diet based on a formula used for Atlantic salmon. By using fewer raw ingredients, researchers produced a feed with fewer antinutrients (substances that interfere with the utilization of one or more nutrients). Trials on Atlantic salmon at the North Attleboro hatchery were successful, but labor-intensive and expensive. Dr. Gannam, along with Bill Fletcher of the Fish and Wildlife Service's Northeast Fishery Center Complex and Dale Honeyfield of the U.S. Geological Survey's Northern Appalachian Research Laboratory improved the formula for Atlantic salmon and adapted it for production by commercial feed manufacturers. The technology they developed is useful to conservation and commerce.
Biologists at North Attleboro NFH now keep about 95 percent of the kelts alive. At the start of the four-week process, the languid fish have to be fed by hand, which has become easier with the development of more palatable foods. The individual females that survive the natural selection process at sea will first yield about 8,000 eggs from the wild. The reconditioned kelts will produce up to an additional 40,000 eggs, thus contributing significantly to future fisheries.
But it is not just Atlantic salmon that are benefiting from this research. On behalf of the Yakama Nation, the Columbia River Inter-Tribal Fish Commission asked Dr. Gannam to create a kelt diet to recondition the threatened winter-run Yakima River steelhead at the Prosser, Washington, tribal hatchery. She worked with tribal biologists and a commercial feed company to change an existing product to meet the needs of their kelt reconditioning program. The modified feed formulation is one that is easier to use, more palatable to the fish, and costs less than the hand-made feeds.
In the end, that means more fish swimming in the water toward recovery.
Craig Springer (craig_springer@fws. gov), a biologist in the Division of the National Fish Hatchery System, is stationed in Albuquerque, New Mexico.
|Printer friendly Cite/link Email Feedback|
|Title Annotation:||FOCUS ON HATCHERIES|
|Publication:||Endangered Species Bulletin|
|Date:||Sep 1, 2007|
|Previous Article:||Sturgeon conservation in the Russian Far East and China.|
|Next Article:||Refuges help recover rare California species.|