Changes In Sport Fish Characteristics And Biomass Of Aquatic Vegetation Before And After Biological Control Of Vegetation In Southern Arkansas  
Brett Timmons and Steve E. Lochmann  

The Ouachita and Saline Rivers, creeks, sloughs, lakes, and swamps cross Felsenthal National Wildlife Refuge (FNWR), the world’s largest green-tree reservoir. The Refuge has developed an aquatic vegetation problem that hinders angler access and has reduced public visits. The three most abundant aquatic vegetation species are American lotus Nelumbo lutea, hydrilla Hydrilla verticillillata, and coontail Ceratophyllum demersum. Aquatic vegetation reduces predator-prey encounter rates, so largemouth bass Micropterus salmoides condition and growth can decline. We sampled fish and vegetation from the FNWR. Largemouth bass and bluegill were sampled with a boat electrofisher. Twenty-meter transects and 1-m² quadrats were used to determine vegetation cover and biomass. The mean (SD) CPUE of largemouth bass was 11 (12) fish/hr and the mean CPUE of bluegill was 59 (75) fish/hr. The mean percent cover was 19 (35)% and the mean biomass was 93 (232) g/m². Twenty-five centimeter grass carp Ctenopharyngodon idella were stocked at a rate of about 5 fish/ha. The fish and vegetation assessments will be repeated in the future to determine changes in those communities due to biological control of vegetation.

The Effects Of Stocking Hatchery Reared Largemouth Bass On The 2007 Year Class Of Wild Largemouth Bass In Backwaters Of The Arkansas River
Jeffrey Horne and Steve Lochmann

In fall 2007, Jolly-Seber mark-recapture studies were conducted to estimate abundance of wild age-0 largemouth bass in 10 backwaters of the Arkansas River. Hatchery-reared largemouth bass were stocked at 60 fish/ha into 5 backwaters. In fall 2008, Jolly-Seber studies were conducted to estimate abundance of wild age-1 largemouth bass. At stocking, there were no differences in weight (T=-0.32, df=8, P=0.76), length (T=0.46, df=8, P=0.66), or condition (T=-0.62, df=8, P=0.56) of wild and hatchery-reared largemouth bass. No significant difference was found between daily instantaneous mortality rates of wild largemouth bass from stocked and unstocked backwaters (T=-0.08, df=7, P=0.94). There was no significant difference in relative weight (T=0.62, df=7, P=0.55) or growth (T=0.06, df=7, P=0.95) between wild age-1 largemouth bass from stocked and unstocked backwaters. In this case, stocking hatchery-reared largemouth bass did not appear to affect the wild year class.

Substrate Composition and Fish Assemblages On Gravel Bars In The Arkansas River
Lael Will and Steve Lochmann

We examined temporal and spatial variability of fish assemblages on 18 gravel bars in the Arkansas River. The influence that specific environmental variables, such as water quality and substrate composition, have on fish assemblage structure was also examined.

Gravel bars were stratified by depth and distance from an upstream lock and dam. Fish assemblages on each gravel bar were sampled six times. Each sample consisted of duplicate trawls using a 3-m Herzog Armadillo trawl. Water quality parameters were measured in conjunction with fish sampling. Substrate samples were collected on each gravel bar using a standard Ponar dredge. The fish assemblages on gravel bars in the Arkansas River are primarily dominated by juvenile Ictalurids, Cyprinids, and Centrarcids. Of those, juvenile blue catfish, channel catfish and silver chub were the most abundant. Fish species richness was significantly different between shallow and deep gravel bars (P < 0.0001) and among the seasons (P < 0.0001). Catch per unit effort (CPUE) for the three most abundant species was analyzed for differences among depths, distance strata, and seasons. There were differences in CPUE among depths (P = 0.03) and seasons (P < 0.0001) for blue catfish. There were differences in CPUE among depths (P = 0.01, P < 0.0001), distances (P =0.04, P < 0.0001), and seasons (P < 0.0001, P < 0.0001) for channel catfish and silver chub. The spatial and temporal variability in fish assemblage structure suggests that shallow gravel bars during the summer and fall seasons may be important habitat for some fish species.

Arkansas River Largemouth Bass Exploitation and Creel Study
Mike Eggleton and Brad Fontaine

Largemouth bass Micropterus salmoides angling is popular throughout the lower Arkansas River. Historically, limited information has been available for Arkansas River largemouth bass populations downstream of Lake Dardanelle.In 2004-2005, intensive studies were conducted that characterized basic population statistics such as abundance, age/size structure, growth, recruitment, and mortality of largemouth bass throughout the lower 11 pools of the river. The next step in this longer-term investigation was the characterization of the angling component of the fishery. Thus, the objectives of this research were to characterize angler effort, catch, and harvest on Arkansas River Pool 4. In September 2007, 845 largemouth bass 330-mm total length and greater were collected, tagged, and released for a tag-rewards study designed to assess largemouth bass exploitation in Pool 4. Concurrently, bus route access-point creel surveys were conducted to generate effort, catch, and harvest statistics, and assess angler satisfaction. After one year of study (October 2007-September 2008), 412 recreational angler surveys were completed. Recreational anglers fished a total of 50,465 hours in Pool 4, or approximately 20.4 hours/ha. Competitive tournament anglers (212 surveys) fished approximately 8,200 hours on Pool 4, which equaled approximately 16% of the total angling effort. >Approximately 28.9% of the tags (232 of 845) were returned as a part of the tag-rewards study. Following adjustment of tag return data for angler non-response, tagging-associated mortality, and tag loss, adjusted catch rates of largemouth bass were 70.3% and adjusted exploitation of largemouth bass was 13.8%. Compared to national averages, largemouth bass exploitation was relatively low in Arkansas River Pool 4, as the fishery appeared to be largely catch and release. Conversely, largemouth bass catch rates were greater than national averages. Levels of mortality associated with routine handling of bass by both recreational and tournament anglers are not currently known. However, mortality could be significant under certain conditions at such high catch rates in the lower Arkansas River.