Catching and releasing fish is an important tool for managing fish populations, but it’s not always effective. Fish hooked in the gills or deeply in the gullet may die after being released. That’s also true for fish caught in deep water.

The North Dakota Game and Fish Department encourages anglers to keep fish caught from water deeper than 25 feet. That’s more conservative than the 30-foot guidance offered in a news release last winter.

Fish landed from deep water often die because of the extreme change in water pressure, which causes the swim bladder to expand. When that happens, fish can no longer control their balance or their position in the water column.

Other internal injuries, such as ruptured organs and blood vessels, might also occur in fish caught from deep water.

Scott Gangl, Game and Fish fisheries management section leader, said this can happen in any deep water body, but it’s especially noteworthy for this time of the year in Lake Sakakawea.

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“As water warms during summer, fish tend to move to deeper, cooler water,” he added. “This is particularly true for walleye in the big lake, where walleye follow their primary forage of rainbow smelt to deeper depths as summer progresses.”

Anglers fishing at least 25 feet deep should make the commitment to keep what they catch, and once they reach their limit to stop fishing in deep water.

“Our simple message is for anglers to keep fish that are caught from these depths, or to fish in shallower water when practicing catch-and-release,” Gangl said.

Catch-and-release tips

Anglers fishing in shallower water planning to release their catch might benefit from the following tips provided by Game and Fish:

  • Land the fish quickly and avoid playing it to exhaustion.

  • Set the hook quickly to prevent the fish from swallowing the bait.

  • Avoid contact with the fish's eyes or gills.

  • Avoid removing mucous or scales that protect the fish.

  • Return the fish to the water quickly.

  • Cut the line close to the mouth if a fish is hooked deeply.

  • Back the hook out opposite the way it went in.

  • Use needle-nose pliers, hemostats or other hook-out tool to remove the hook and protect your hands from toothy fish.

  • Try to resuscitate an exhausted fish by moving it forward to force water through its gills.