Releasing a rockfish can be a bit complicated, and more than a bit daunting for a first-time rockfish angler trying to preserve these long-lived creatures. Rockfish can live for many decades and the oldest have broken the 100-year mark, with a 200-year-old fish in the realm of possibility.
Rockfish reside in deep waters and are not used to the low pressures of surface. During an angler-sponsored trip to the surface, rockfish undergo rapid decompression and a condition known as barotrauma. This causes the fish’s internal organs to inflate with gas and its stomach to protrude through its mouth. Although it is not usually fatal in itself, it renders the fish helpless if it is soon released on the surface after being caught.
For the conservation-minded angler, there are numerous methods to release rockfish deeper than the surface to give them a better chance of survival. Many of these, such as the milk box technique, are relatively inexpensive and easy to master with practice. The added effort may well be worth it, a recent Alaska Department of Game and Fish survey found that fish released at depth have 98 percent survival rate when compared to fish released on the surface, only 22 percent.
Here is a video that gives an introduction on some popular methods in releasing rockfish. Like all good educational videos, it includes what appears to be biologists rapping.
Biologists caution anglers not to intentionally target rockfish for catch-and-release because of high mortality rates. However, these methods are a great to return an unwanted or surplus catch.