By Brett Hobbs- Asst. District Fisheries Biologist, Arkansas Game & Fish Commission
The Lake Ouachita Nursery Pond, when filled to capacity, is
a 21 surface acre pond located on the
western side of the South Fork Ouachita River directly across from the Corps of Engineers Joplin area.
The use of a separate structure "nursery pond" to raise Striped Bass fry to
fingerling size fish, then draining them directly into Lake Ouachita has been highly
successful in establishing measurable populations of Stripers.
By raising the fish to fingerling size (2 ½ inches) many are able to escape predation to which they would have been exposed if stocked as fry. The Lake Ouachita Nursery Pond, when filled to capacity, is a 21 surface acre pond located on the western side of the South Fork Ouachita River directly across from the Corps of Engineers Joplin area.
The nursery pond is also used to produce other species such as largemouth bass and walleye. The pond has a gate which is closed during the winter months to catch rainfall runoff from a couple of creeks which flow through the pond bottom. Usually by end of March there is sufficient water in the pond to raise a fish crop. When made available from the hatchery system, the fry are stocked into the fertile pond to begin their growth to the desired fingerling size.
In anticipation of the striped bass crop certain measures are taken to prepare the pond and provide the fry with their best chance for growth and survival. As the pond gate is closed the water in the creeks is treated with a fish toxicant, rotenone, to make sure no wild fish will be in the pond which might prey on the stocked fry. Later the pond is fertilized with organic and inorganic fertilizers to stimulate plankton blooms. Large hay bales, scattered in the pond bottom before filling, will serve as organic fertilizer to increase the amount of food available to the larval fishes. Sometimes alfalfa pellets or cottonseed meal is used in addition. Granular fertilizers are later added to increase the phosphorus and nitrogen available in the water. As the water becomes greener with phytoplankton (small aquatic algae), a zooplankton community (small aquatic insects) begins to prosper. This plankton will be the initial food supply for the developing striped bass fry.
Lake Ouachita is currently receiving a nursery pond crop of stripers approximately once every third year. Typically during years in which the pond is not used for striped bass production, some fingerlings are stocked by fish truck from the hatchery system as they are available. During most years there will be striped bass stocked into Lake Ouachita in some amount. During years in which the nursery pond is scheduled for striped bass, 1.0 to 1.5 million fry are stocked into the pond in mid to late-April. These fry are usually 4 to 5 days old when stocked into the pond and have absorbed the majority of their yolk sack and have developed mouthparts. At this point the fry are able to swim in a straight line and are ready to begin foraging plankton.
Biologists charged with managing the pond will periodically seine check the developing stripers to check on survival and growth. A good year of production might be 30% survival of the fry. Survival depends on many factors (condition of fry at time of stocking, available food supply , water quality, & predacious insects). That potential trophy must beat the odds and make it through the critical fry stage to continue to grow to fingerling size. This process will generally take a couple of months. Once the fingerlings reach about a 2 ½ inch average size the crop is ready for release. We would have a good year if we are able to turn out 450,000 striped bass fingerlings from the pond. The gate is opened and allowed to drain directly into the lake over a period of about 2-3 days depending on the lake level.
During April of most years the Commission conducts a striped bass spawning project at
the Andrew Hulsey State Fish Hatchery located on Lake Hamilton south of Hot Springs. Staff
biologists will utilize commercial tackle, gill nets, to capture broodstock adults from
Lake Ouachita in the South Fork arm of the lake.
Eligible adults are taken via hatchery fish trucks from the lake back to the hatchery for spawning. Eggs are stripped and fertilized at the hatchery as the individual females ovulate. A typical project may span two weeks, 24-hours a day. Fertilized eggs are moved to hatching jars and after about 3 days the eggs will hatch.
It is typical for production from one year of the project to be around 4 to 5 million striped bass fry. Hybrid striped bass are also produced during the same project. The main lakes which receive hybrids will be Greers Ferry Lake and DeGray Lake.
Food for thought: A "trophy" 40-50 pound striped bass caught on Lake Ouachita was likely raised by the Game and Fish Commission Fisheries Division during one of its spawning projects. That fish may be 12-15 years old.
Arkansas Stripers Site Map