Tennessee Wildlife Resources Agency biologists are currently monitoring Dale Hollow Reservoir on the Tennessee-Kentucky border, where significant walleye mortality has occurred.

They say the combined effect of high water temperatures, low dissolved oxygen, reduced flow and changes in water level have contributed to the deaths of numerous walleyes. Biologists say about 250 dead walleyes have been spotted so far. The Horse Creek and Mitchell Creek areas at the lower end of Dale Hollow are being monitored particularly closely.

They say walleye, a very popular sport fish that seeks out baitfish and cooler water temperatures, can fall victim to low oxygen levels in the water. They say the die-off is weather-related and not due to any type of pollution.

Ellis Bevill, a former Chattanooga resident but now living in Dale Hollow, said he first noticed the dead walleye last Friday. Bevill said he also saw some dead herring, a baitfish commonly used by walleyes.

TWRA biologists said a similar mass die-off occurred in Dale Hollow in 2012 when similar conditions existed.

They say the poor conditions are primarily affecting walleye. But they add that if the weather and water conditions don’t change, other game species could be affected. In 2012, both game and non-game species were affected, including walleye and bass. Anglers have seen these occurrences in other reservoirs, such as Center Hill. In these deep, low-flow lakes, the water “stratifies,” creating areas where the water temperatures best suited to certain fish don’t contain enough oxygen.

Biologists say that in previous mass die-offs in Dale Hollow, populations were resilient to such events and had no long-term impact on populations. TWRA staff say they will continue to monitor and manage fish populations.

Dale Hollow is home to the world record largemouth bass (11 pounds 15 ounces) caught by DL Hayes in 1955.