Catching and releasing fish from deep water can kill them
South Dakota Glacial Lakes
Fish conservation
Catching and releasing fish from deep water can kill them
by Brian Blackwell Fisheries Biologist, Webster, South Dakota
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The 2025 South Dakota Governor’ s Walleye Cup took place on Lake Oahe from July 19-20. Several large walleyes were weighed, including some exceeding 11 pounds. The top seven teams had total weights exceeding 41.5 pounds over the two days( six walleyes were weighed per day, with only two over 20 inches), with the winning team posting an extraordinary 61.5 pounds. The results were impressive, but not unexpected, as Lake Oahe has again become known for producing large walleyes.
People began taking notice of the recent surge of big Walleyes from Lake Oahe in 2021, and it may have peaked during in 2023. In the fall of 2023 the South Dakota hook-and-line walleye record( 16 lbs 2 oz. from 2002) was broken twice. The first record-breaking walleye weighed 16 lbs. 8 oz., caught on October 27, 2023. The current record, a 17-lb. 13-oz. walleye, was caught on November 11, 2023. Although this record has not been surpassed since 2023, many large walleyes continue to be caught from Lake Oahe, suggesting the potential for a new record in the future.
The fall season has become a popular time for anglers targeting large walleyes on Lake Oahe. Many of these big walleyes are caught in deep water where they follow food sources like cisco and smelt. In the fall these prey fish are typically found in the deep-water areas between Mobridge and Gettysburg, drawing walleyes. The high abundance of these cold-water prey fish has contributed to the current high numbers of big walleyes in Lake Oahe.
Now that I have set the stage about the big walleyes caught from deep water on Lake Oahe during fall, let ' s move on to the main topic of this article: Barotrauma. If you’ re a regular reader of Dakota Country, you might remember a previous article I wrote on this. I’ m revisiting barotrauma because it’ s important for anglers, especially those fishing in deep water, to understand its potential effects.
In fish, barotrauma occurs due to rapid changes in pressure when they’ re brought to the
Page 18, Dakota Country, September 2025 www. dakotacountrymagazine. com