https://www.sciencedaily.com/releases/2020/12/201202192730.htm

The analysis estimates fish populations and harvest rates based on the numbers of larger, older fish present; fewer larger fish is an indication of higher harvesting rates. Researchers found harvest rates essentially at zero for four species of kelp forest fish inside the marine protected areas between 2003 and 2017, but found much higher rates of harvesting at unprotected sites nearby.

"We expected we would find more large fish in the marine protected areas, and that is exactly what happened," said Will White, a marine ecologist with Oregon State's Coastal Oregon Marine Experiment Station in Newport and the paper's lead author. "We looked at the data inside and outside the marine protected areas and we found that there is no evidence of fishing inside the boundaries, but there is a lot of fishing going on just outside the boundaries."