Fish die-off at Table Rock sites caused by natural events

BRANSON, Mo. – A convergence of natural events detrimental to fish health has led to an abundance of dead fish seen at several spots on Table Rock Lake in recent weeks.

Although seeing multiple dead fish floating in the water is alarming, Missouri Department of Conservation (MDC) biologists say the lake's health and overall water quality are fine. What people are seeing at some spots on the reservoir is simply the results of several factors that, when combined, can be fatal for fish.

Initial observations of dead fish were made during the week of July 27 in Barry County on the lake's western part. On Friday (Aug. 14), MDC biologists investigated reports of dead fish seen in the Kings River Arm (also in Barry County) and in the Long Creek Arm (Taney County). Gizzard shad and suckers comprised the bulk of the dead fish, but some sportfish species (crappie, black bass, etc.) were observed, too. MDC staff received a report of dead fish in the James River Arm (Stone County) of Table Rock on Wednesday (Aug. 19). Suckers were the only species reported for this event.

Based on observations and readings that have been taken, depleted oxygen appears to be what caused the fish to die at all sites. In these occurrences, low oxygen levels are the final result of a chain of events that began with recent heavy rains.

"Parts of Table Rock have turned a greenish color in recent weeks in response to a large planktonic algae bloom," MDC Fisheries Biologist Shane Bush said. Bush oversees fishery management at Table Rock Lake. "This is very common when water temperatures warm up following high inflows of water into the reservoir." In Table Rock's case, these high inflows came during heavy rains that occurred in recent weeks.

"The water that flows into the lake during flood events is often high in nutrients such as phosphorus and nitrogen, which fuels the growth of algae," Bush said. He explained that when the algae die off, they use up much of the oxygen in the water. High temperatures experienced the past couple of weeks exacerbated the situation because the warmer the water is, the less oxygen it can hold. Put these factors together and it creates spots where it's extremely hard for fish to survive.

Bush says it may take a number of weeks for some spots to cycle through this phase, but added that any additional fish die-off events that occur in future weeks will likely be relegated to smaller sections of the lake.

Bush encourages anglers who observe dead fish on Table Rock to contact him at 417-334-4859 or at shane.bush@mdc.mo.gov.