Evaluating the Efficacy of Marine Protected Areas

The Bangrin Mangrove Marine Protected Area situated at Bani, Pangasinan, Philippines. (Credit: Emman A. Foronda via Wikimedia Commons CC BY-SA 4.0)

Managers of multi-use fisheries face the complex challenge of managing anglers and biodiversity needs in addition to ensuring that fishery resources are protected. One strategy that resource management departments have implemented in saltwater fisheries is the establishment of marine protected areas (MPAs), which can vary in size, age, and effectiveness.

Though managing harvest-based or multi-use fisheries can be challenging, sustainability is at the forefront of the decision when establishing an MPA. Whether it be restrictions on fishing or the establishment of a no-take zone, the protections outlined in an MPA are designed to help the natural ecosystem recover.

Effective MPAs yield growing fish stocks, recovering habitats, and other changes that ultimately improve the overall health of the ecosystem. Because MPAs are established in regions that have been impacted by other stressors, such as climate change, pollution, and overfishing, time and conservative use of fishery resources are key to maintaining these environments.

Drivers of Success of Marine Protected Areas

MPAs can be found all over the globe, even popping up in the Arctic, and the success of each region has varied depending on a few key variables. A 2023 study published in Conservation Letters found that reserve size and age were the strongest drivers of MPA efficacy.

California’s extensive network of MPAs was selected as the focus of this study due to the variety of sites and the availability of angler and population data. More specifically, 12 no-take or highly protective limited-take MPAs were examined and then paired with fished reference areas across the 1100 km of coastline to evaluate the factors driving MPA efficacy across a large geographic region.

Examining data across the network of MPAs and assessing California Collaborative Fisheries Research Program surveys, the study found that larger and older areas were more successful, resulting in increased fish catch, biomass, and positive species responses. The study also notes that ” likely some combination of latitude, fishing pressure, and temperature had significant effects on the strength of the MPA response.”

Conclusion

While the results of this study found age and size to be the greatest drivers of MPA success, meta-analyses highlight temperature, latitude, fishing pressure, depth, and connectivity as additional influences. 

The data collected by the study serves as a good reference for managers to consider when establishing new MPAs or improving upon existing MPAs. The study also concludes that the framework for determining efficacy can be applied elsewhere and will hopefully equip managers with the data needed to make their MPAs successful through collaboration and engaging with local stakeholders.

One Comment

1. Pingback: FishSens Magazine | Managing Fisheries Within and After Fishing Bans: The 10-Year Fishing Ban in the Yangtze River - FishSens Magazine