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Lake Ouachita Striped Bass:
The Use of Nursery Pond Stocking
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.
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