Fishermen are innovative people and for some, it is the best part of fishing. I know guys that spend 90 percent of their time messing with their gear and only 10 percent of their time actually fishing. So it is not surprising that fishermen solved the problem of barotrauma in rockfish.
When most species of rockfish are caught in deep water, the change in pressure as they are reeled to the surface causes the gas in their swim bladder to expand. While in that state, it is almost impossible for that fish to swim back to the bottom without aid. Obviously that is not a problem if you plan to keep the fish but if you want to release that fish the chances of its survival are slim. That has now changed thanks to some creative fishermen.
Yelloweye and canary rockfish are protected by law and when an estimated number of them are caught as bycatch then all rockfishing is closed. The DFG also estimates the survival rate of released fish and currently the estimated mortality rate is high. That means we will reach our bycatch quota quicker, closing the season sooner.
Some fishermen do not realize that when a fish suffers from barotrauma their stomach extends out of their mouth and poking a hole in the stomach does not relieve the effects of barotrauma on the swim bladder and only does more harm to an already disabled fish. Even when done properly, venting the swim bladder with a needle still damages the bladder.
The solution is to return the rockfish to the depth it was caught as quickly as possible so the high pressure can reverse the effects of barotrauma. Kevin McGrath said his buddies at Shelter Cove started using a weighed milk crate placed over a floating fish that is then lowered with a rope. Once it gets to depth the fish swims away. Janz ties a cord to a barbless hook with a swivel attached to the eye to hold the weight. The fish is hooked in the lip and the weight pulls the fish down to depth. A quick tug on the cord pulls the hook free releasing the fish. Phil Glenn used his wife’s corn bread pan to mold lead around a large hook. His design is neat because the lead acts as a handle for easy use. The method is the same, drop it down and jerk it to release.
The other commercial descender is made by Git-R-Down (http://git-r-down.com) and features a grip that pinches the fishes lip instead of puncturing it. Again, once it is lowered to depth a quick jerk releases the fish. The company claims their release device eliminates the possibility of infection from the hook puncturing the lip and the possibility of the fish escaping the hook before it reaches the proper depth.
An Oregon State University study last year showed 80% of black rockfish that were brought to the surface rapidly suffered ruptured swim bladders. After 31 days almost half of those swim bladders had not yet healed although none of the fish died and 80% of those fish resumed feeding. They recommend using a descender as quickly as possible and not handling the fish out of the water. Have a separate rod dedicated to releasing fish and if you are catching protected fish, simply move to another spot.