Old Is Gold for Marine Protected Areas

A team of 24 scientists has found that California’s marine protected areas (MPAs) in the U.S. significantly benefit sea life, especially species targeted by fisheries, thanks to habitat diversity.

“MPAs are always designed to protect multiple habitats, but they are rarely evaluated with all of the different habitats in a single study,” explains Jennifer Caselle, a research biologist at UCSB. “And that’s in part because scientists specialize. But California supports broad monitoring efforts across its marine reserves, and this paper analyses all these habitats at once.”

The huge state-wide network of 124 MPAs was created following adopting the Marine Life Protection Act in 1999, which required the state to overhaul its marine reserves. A constellation of smaller MPAs distributed across the coast was explicitly engineered to interchange animals, plankton, and nutrients between different reserves. Scientists used long-term data on 170 taxa from the MPA monitoring efforts of four groups each focusing on a different habitat – the surf zone, kelp forest, shallow reef, and deep reef – to evaluate the conservation performance of 59 MPAs in California’s marine network. Older MPAs have a greater diversity of habitats, showing the highest amount of fish biomass, mainly among targeted species like rockfish. When different habitats coexist, there is more variability in the types of foods, resources, and shelter, all things marine species need to survive and thrive.