Fishing is considerably easier around California's marine protected areas (MPAs) after more than ten years of preserved status, as researchers from the University of California Santa Barbara recently concluded in a study they published in the journal Scientific Reports.

"The Channel Islands MPAs appear to be fulfilling their role as refuges for many fish and invertebrate species," Jennifer Caselle, a research biologist at the University of California, Santa Barbara's Marine Science Institute, said in a release.

State waters surrounding the northern Channel Islands, near Santa Barbara, were established as MPAs starting in 2003. Since then, NOAA stretched the MPAs to include the Channel Islands National Marine Sanctuary. The recent study is the conclusion of 10 years of monitored data in the Channel Islands MPA network.

Fishermen are finding a higher number of fish per area and a more significant total weight in fish per area inside the MPAs as compared to sites well away from the preserved areas, the scientists concluded. This was true in 2008 and in the more-recent data from 2013, the team said in the release.

After the MPA area was set aside and preserved from fishing, fishermen feared that having to look elsewhere for fish would deplete stocks in other areas, as study co-author Robert Warner notes. "Happily, there is no evidence of depletion. In fact, fish stocks outside of MPAs have increased over time, although at a slower rate than inside MPAs."

Researchers are still working on learning whether the increases in fish population outside of the MPA borders are connected with less fishing pressure, spillover from the protected areas, positive environmental conditions-or a combination of all of these.