Fish Kill On Bull Shoals

[Phil Lilley]

Heard about this last night- got this email from AJ Pratt, MDC biologist:

Fish continue to die at Bull Shoals and it appears it is expanding to other areas of the lake. As a result, I’ve received a number of phone calls from anglers concerned about the situation and wondering what can be done. Below is a brief history of the kill and talking points in case you are contacted by the public/media.

History:

Reports of dead walleye began the week of Sept. 5 in the Lead Hill area and has now expanded below the Oakland area (Points 3-9). Initially, walleye and striped bass were the only fish affected, but as of Tuesday (9-13-11) yellow perch, suckers, drum, and longear have also been reported as dying.

Talking Points:

- Poor water quality is the primary cause for the fish kill.

- Water quality measurements (temperature and dissolved oxygen) reveal water temperatures, from the surface down to 30 feet, range from 80 to 75 degrees F, respectively. Meanwhile, oxygen concentrations are adequate, from the surface to 30 feet, and range from 9 ppm to 6ppm, respectively. However, oxygen levels, from 30 to 35, feet drop to almost nonexistent (2 to 0.1 ppm). Fish become stressed when levels are under 3 ppm. Water temperatures below 30 feet cool to 72 degrees F.

- Since walleye/striped bass/yellow perch/drum are a cool water fish, they cannot inhabit the cooler water found below the 30 foot depth. As they are forced to stay in the warmer water they are becoming stressed with some even dying.

- Due to the extreme high water, the thermocline usually sets up higher in the water column as compared to years with normal water levels. Also, due to the decomposition of organic material, washed in from the spring floods and surrounding vegetation, oxygen levels below the thermocline are extremely low. This combination forces fish to stay in the upper water column. In typical years, oxygen levels, below the thermocline, remain high enough for fish to survive for short periods of time.

- The same situation happened in 2004, another high water year, when walleye, drum, and blue catfish died.

- Currently, there has not been any record the water quality is negatively affecting other popular gamefish (black bass, catfish, and crappie).

- It is unclear how significant the kill is at this point.

- MDC staff continue to monitor the die-off.

- Fish kills are currently happening in other White River reservoirs (Norfork and Beaver) and are mainly affecting striped bass.

If you have additional questions, do not hesitate to contact me. Thanks.

A.J. Pratt

Fisheries Management Biologist

Missouri Dept. of Conservation

551 Joe Jones Blvd.

West Plains, MO 65775

(417) 255-9561, ext. 277

Anthony.Pratt@mdc.mo.gov

[abbfish]

Where is the thermocline now?

[Phil Lilley]

I would say by AJ's writing it's at 30 feet

[Martin]

Hopefully this cooler weather will help. The surface temp and on down to 30 feet or so should cool and slow the decay of all the vegetation and help de-stress the fish... Hope the cool down helps before the turnover later in the year.

[Mike Worley]

I have fished the point 3 to point 16 area several times in the past week. I did see a few dead fish in those areas, but only a few. A couple of stripers and 4 or 5 walleyes over the course of about 4 days of fishing with most of them floating in the point 7 to point 12 area. let's hope that the cooler weather and rain will help.