Barotrauma observed in yellow walleye

Issued on 18th July 2017

During a day of fishing, you may have seen a fish whose eyes seemed bulging or that it's stomach had been expelled from his mouth. These are signs of barotrauma or barometric shock.

Barotrauma is the set of injuries suffered by a living being as a result of a rapid change in barometric pressure. Because of their particular anatomy and affection for the deep, yellow walleye is very likely to be affected. Indeed, the greater the depth of fishing, the greater risk for barometric shock. The main symptoms observed are :

  • loss of equilibrium;
  • Abdomen distended;
  • Eyes bulging;
  • Stomach expelled by the mouth;
  • Intestine expelled by the anus;
  • Presence of blood under the skin near the eyes and on the fins.

Due to the regulations issued under the Quebec Walleye Management Plan (2016-2026), some catches must be released in the water (total length less than 32 cm, total length greater than 47 cm). When a walleye has one of the above symptoms and does not comply with the permitted size limits, it must be returned to the water while taking certain precautions to ensure its survival. The following recommendations improve the chances of survival for the affected.

Avoid prolonging the fight. Reassembling the fish slowly does not allow it to adjust it's swim bladder to the pressure change. To do this, it would take several hours. This only increases the duration of the fight, which tires the fish and reduces its chances of surviving the release.

Proceed with fish release as quickly as possible, ideally avoiding getting it out of the water. This allows less time for the gases inside it's swim bladder to expand.

When fish have suffered barometric shock and show loss of balance preventing it from returning to the bottom, keep it, of course, if the regulations allow it, and consider it within the daily limit. Regulatory compliance, as well as the practice of these recommendations, improve the survival of spawners. In this way, a good quality of fishing is ensured for years to come.

Good fishing !

By Mélissa Jeanson, Gouin Reservoir Management Corporation

Categories  :   Fishing

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