AR: Oxygen Levels Monitored at Bull Shoals, Norfork Dams

MOUNTAIN HOME, Ark. – This year’s spring rains provided many benefits for the state’s fisheries. The abundant rainfall provided additional water to local fisheries, improved the recruitment of young bass within the lakes, and provided sufficient amounts of cold water to support the trout fisheries below Bull Shoals and Norfork dams through the summer. Along with these benefits, come some challenges.

Flooded boat ramps and access areas were some of the most immediate and visible impacts. Another challenge that many may not be aware of and one that usually follows a high rainfall spring and high flow summer, is reduced water quality in tailwater trout streams.

This season’s most severe low dissolved oxygen conditions are occurring in the Bull Shoals and Norfork tailwaters. These conditions can have significant impacts on trout to include slowed feeding, which can result in lower angler catch rates, poorer health and condition, and ultimately reduced growth and survival, according to the AGFC’s trout biologist Jeff Williams. "As members of the White River Dissolved Oxygen Committee the Arkansas Game and Fish Commission, the U.S. Army Corps of Engineers and the Southwestern Power Administration are working together to monitor and address the dissolved oxygen issue," Williams said. "Specifically, these agencies follow the steps outlined in a plan of operation for the low dissolved oxygen season," he added.

Under the Operation Action Plan for 2011, the AGFC will cease stocking trout in any river reach where the dissolved oxygen is less than six milligrams per liter during the period of time planned for the trout to be stocked. Trout are not stocked in areas with low dissolved oxygen to avoid stressing the fish as they are stocked. "This also allows the remaining trout the best opportunities for survival should conditions continue to decline," Williams explained.

Trout stocking activities have ceased in the upper 12 miles of the Bull Shoals Tailwater and the upper 2 miles of the Norfork Tailwater. Trout that are not stocked in the scheduled locations are redistributed at nearby sites downstream. As conditions improve, the normal stocking schedule will resume.

Conditions this year are relatively bad because of the large amount of rainfall this spring and the heavy releases throughout the summer, Williams says. "We expect these conditions to continue through this fall until sometime in December when surface water cools and winds are able to remix and re-aerate the lake," he said.

Williams said that although stocking has ceased in these limited reaches, these areas are still fishable and there are still trout there. "There also is plenty of water where stocking continues as normal and where anglers can take advantage of the great fishing we have seen this summer," he added.