**This blog entry orginally appeared on the website oceanspaces.org.**/p>
In 2003, a network of MPAs was implemented in the northern Channel Islands, home to the Channel Islands National Marine Sanctuary and the Channel Islands National Park. Now part of the South Coast region of the Marine Life Protection Act, these MPAs celebrated their 10th anniversary in 2013. In 2008, a five-year evaluation was done, and the results were presented at a special symposium and distributed in an easy to read brochure (http://www.piscoweb.org/policy/marine-protected-area-policy/monitoring-marine-protected-areas-/channel-islands-marine-protec). Many research, agency, citizen science and fishermen groups contributed to this evaluation and all agreed that while five years was not enough time to see dramatic changes in the ecosystem, interim results can be useful in providing a glimpse of the changes that might come as well as the types of information that are used in evaluating MPA effectiveness. The five-year report documented patterns in the communities of animals occupying shallow kelp forests to deepwater habitats as well as changes to both recreational and commercial fisheries.
Well, we’ve been busy since then, and monitoring has continued throughout the Channel Islands, not to mention the South Coast region as a whole. Many groups including the Partnership for Interdisciplinary Studies of Coastal Oceans (PISCO), the National Park Service, ReefCheck CA and MARE continue to monitor various subtidal habitats in the Channel Islands. There are also 10 state-funded projects conducting baseline monitoring of ecosystems and human uses for the entire South Coast MPA network, which includes the Channel Islands (the results of these projects will be available soon on OceanSpaces).
Our group, PISCO, recently completed an update to the results we presented back in 2008 on the patterns of kelp forest organisms inside and outside MPAs. The five-year review of the CI MPA network focused primarily on spatial patterns and less on changes over time. We are excited to report that the initial positive trends that we saw in 2008 are continuing. At that time, we showed that the abundance (numbers of fish) and biomass (total weight of fish) of fish species targeted by fishermen in the region were both greater inside the reserves relative to the outside reference sites. Non-targeted fish species did not show these same differences between MPA and open areas. Using 10 years of data, through 2012, we now find the same patterns with even larger differences between protected and unprotected sites.
What’s really new is that with 10 years of data under our belts, we can now measure the trajectories of change over time, both inside and outside of MPAs. Trajectories of biomass and density of kelp forest organisms require longer time series to detect increases or decreases against a backdrop of natural year-to-year variability than were available at the five year mark. We are finding that the average biomass of targeted fish species is increasing inside MPAs compared with outside reference areas. However, these targeted fish species are also increasing outside MPAs, just not as fast as inside. This result is reassuring in that it suggests that any shifts in fishing effort due to MPA placement are not severely overtaxing the fished biomass nearby the MPAs. Similar to results from 2008 and not unexpected, we did not find a significant MPA effect for non-targeted fish species.
We focus much of our analyses on the differences between targeted (i.e. fished) species and non-targeted species as we hypothesize that the effects of MPAs, by eliminating fishing pressure, should be greatest and occur earliest on those species that are directly targeted by fishing. That is not to say that we don’t expect effects on non-targeted species. Many non-targeted fish species are prey for the larger, predatory species that also are highly sought by fishers. Over time, we do expect reserves to affect these non- targeted species through trophic interactions or what are called indirect effects. Indirect effects are known to take longer to occur and will require a much longer monitoring timeseries so stay tuned for those results in the next few years.
For more information see:
A Decade of Protection: 10 Years of Change at the Channel Islands
Hamilton, SL, JE Caselle, DP Malone, MH Carr (2010) Incorporating biogeography into evaluations of the Channel Islands marine reserve network. Proceedings of the National Academy of Sciences 107 (43): 18272-18277
California Department of Fish and Game, Partnership for Interdisciplinary Studies of Coastal Oceans, Channel Islands National Marine Sanctuary and Channel Islands National Park. 2008. Channel Islands Marine Protected Areas: First Five Years of Monitoring 2003-2008. Airame, S. and J. Ugoretz (Eds). 20 pg. www.dfg.ca.gov/marine
Finally, a big shout out and thanks to all our partners and funders on our long-term monitoring efforts. These include: David and Lucile Packard Foundation, Gordon and Betty Moore Foundation, Channel Islands National Park, NOAA, National Science Foundation, CA Department of Fish and Wildlife, Channel Islands National Marine Sanctuary, CA Ocean Protection Council, CA Seagrant, Resources Legacy Fund.