- Stocking hatchery-reared fingerlings to improve largemouth bass population in the Arkansas River
Steve Lochmann
Arkansas largemouth bass anglers are concerned about the low number of large bass (>5lbs) in the River and the general health of the population. The Arkansas Game and Fish Commission (AGFC) is stocking largemouth bass fingerlings in the Arkansas River as a means of rebuilding depleted stocks. This stocking program is quite expensive, but the positive impact of stocking on Arkansas River populations of largemouth bass has not been demonstrated. It is
also unclear which are the most appropriately sized fingerlings to stock. Larger fingerlings (>50mm) are less expensive to raise but have poorer survival.
In collaboration with the AGFC, 50,000 50-mm bass fingerlings, marked with oxytetracycline hydrochloride (an antibiotic chemical) were stocked into pools 5 and 9 of the Arkansas River. When these fish are recovered, their otoliths (ear bones) will glow under black light, indicating that they were raised in a hatchery and stocked by AGFC. We collected fish samples from pools 5 and 9 in the fall of 2002 and spring of 2003. Our research suggest that between 15% and 20% of fish in these pools born in 2002 are from the hatchery. We stocked 50-mm or 100-mm fingerling bass into 10 coves of pool 4 during the summer of 2003 to see whether the extra expense of raising 100-mm bass was worthwhile. We sampled fish from each cove in autumn of 2003 to compare relative contributions to the 2003 year class of each size group.
Supplemental stocking has potentially increased the year class by 20%. These results are likely to guide the supplemental stocking efforts of the Arkansas Game and Fish Commission and other state natural resource agencies interested in using supplemental stocking as a management tool for largemouth bass.
- Characterization of Floodplain Lake Fish Assemblages in the Lower White River, Arkansas
Ben Lubinski, Mike Eggleton, John Jackson, and Steve Lochmann
Although modified by upstream impoundments that affect both hydrologic and thermal conditions, the lower White River presently represents one of the least altered floodplain river ecosystems on a developed continent. The White River contains a diverse fish assemblage with excellent recreational fisheries for crappie, black bass, catfish, and sunfish as well as commercial fisheries for catfish, buffalo, and gar. In addition, the White River FRE supports species of interest that include paddlefish, alligator gar, and blue sucker. Backwater lakes provide habitat for wetland species such as shiners, pirate perch, and backwater darters.
We sampled the fish communities of eight floodplain lakes using electrofishing, mini-fyke nets, and gill nets. We also characterized the lakes with respect to area, depth, and other physical attributes. We are using multivariate statistics to define relationships between fish community structure and lake characteristics. The fish community structure tended to vary with size and average depth of the floodplain lakes. We will be sampling an additional twelve floodplain lakes during both high and low water to further characterize fish community structure and to determine the influence of hydrography and connectivity to the main channel of the White River on fish community structure.
- Assessment of Impacts of Proposed Navigation and Water Withdrawal on Fishes in the Lower White River
Mike Eggleton, Hal Schramm, John Jackson, and Steve Lochmann
The value of the natural resources of the White River Basin is recognized by the area's designation as a Wetland of International Importance. The Basin constitutes one of the Nation's largest remaining intact forested wetland landscapes. It supports the North American continent's largest concentration of over-wintering mallard ducks, a productive big river fishery, and several threatened and endangered species. The continued viability of this floodplain-river ecosystem depends on the suitability of the hydrologic environment to the resident flora and fauna. Given the critical role of hydrology in regulating the structure and function of floodplain-river ecosystems, alterations have cumulatively degraded the habitat value of this resource for fish and wildlife in the Basin. In spite of the enormous stakes involved, there have been no studies relating fish and wildlife resource responses to past and future cumulative hydrologic alterations in the Basin.
We are developing a Bayesian belief network for the fish of the White River ecosystem. This model is a tool that effectively identifies key components that affect ecosystem structure and function, predicts impacts of habitat change, and, through sensitivity analyses, prioritizes management and research activities. The model is based on current and future habitat conditions and synthesis of existing life history, distribution, and abundance information for fishes and mussels. The model will aid state and federal natural resource managers in determining risks to habitat changes and in prioritizing research needs.
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