Case Studies

Context and challenge

Figure 1. Ocean temperature gradient in the Channel Islands and surrounding waters exhibits a mixing of cold and warm waters that host vast assemblages of biodiversity. Climate-change driven warming affects marine species and therefore threatens biodiversity (NOAA).

The Northern Channel Islands are a chain of remote islands that extend 240 km (150 miles) along, and about 20–115 km (12–70 miles) off the coast of southern California in the Pacific Ocean. The waters surrounding the islands are high in primary productivity and biodiversity driven by nutrient upwelling and regional positioning between warm and cold bioregions. It hosts a range of marine habitats including inshore kelp forests, rocky reefs, and deep-sea coral gardens. Kelp forests, in particular, support some of the most species-rich ecosystems on Earth. Abundant small schooling fish assemblages like anchovies and sardines establish a wide base to a food chain that includes seals, sea lions, orca, seabirds, and large fishes. Blue whale and sea turtles are also represented in Northern Channel Island waters (California Department of Fish and Wildlife). 

With the impacts of historical overfishing decreasing due to effective protections, other threats currently predominate in the Northern Channel Islands. Climate change increases water temperatures and threatens to alter the marine communities in the Channel Islands from one uniquely straddling cold and warm waters to one of predominantly warm waters (figure 1) (NOAA). One of the largest threats are oil spills, as numerous active oil platforms and wells with underwater pipelines line the nearby Santa Barbara Channel (figure 2) (Fractracker). Human impacts also threaten system function in the Northern Channel Islands, particularly fisheries pressures on populations and introduction of invasive species.

Figure 2. Offshore oil rig platforms (red squares) and offshore oil and gas wells (blue dots) located between the Northern Channel Islands and the California mainland (fractracker).

Approach

The Northern Channel Islands marine protected area (MPA) network covers 3,804 square kilometers (1,469 square miles) and includes 11 state and federal no-extraction Marine Reserves and two no-extraction Special Closure Areas (figure 3). These no-extraction areas restrict fishing, oil, and mining activities, with the exceptions of limited fishing of lobster and fish that feed near the surface in two of the areas. Protections extend from state to federal waters and from the intertidal zone to depths of 1,400 m (4593 feet). 

Success in this network is often attributed, in part, to the comprehensive and stakeholder-driven planning process preceding implementation and continued throughout expansions and developments. This social connectivity and open communication often produces protection results that are more informed, and more respected by diverse groups. By integrating regional scientific knowledge, engaging local communities, and evaluating the potential economic impacts of marine protections through a multi-year public process, in 2003 the state of California successfully designated 13 areas within state and national park waters all at once, in collaboration with Channel Islands National Park (CINP). In 2007, the National Oceanic and Atmospheric Administration (NOAA) extended eight of these MPAs into Channel Islands National Marine Sanctuary (CINMS) waters (figure 3). The MPA network is managed by three entities: the Channel Islands National Park, the Channel Islands National Marine Sanctuary, and the California Department of Fish and Wildlife, working together to create regulations and facilitate enforcement. The agencies continue to include a participatory approach to conservation, engaging ancestors of the Indigenous coastal people, the Chumash, as well as other local community members in MPA developments. Public engagement also extended to a post management implementation plan (Environment America; Watson et al. 2010).

Though not originally designed as a network of MPAs connected to one another by the dispersal of young (i.e., fish and invertebrate larvae), subsequent analyses of oceanographic currents and larval dispersal patterns indicated that young generated in the MPAs very likely are transported to and contribute to the replenishment of populations and communities in other MPAs, thus forming a de facto network. Ocean circulation models were used to predict larval dispersal of two important fishery species – kelp bass (Paralabrax clathratus) and kelp rockfish (Sebastes atrovirens) – to and from sites throughout southern California, including the Channel Islands MPAs. The analysis showed that both species’ larvae were likely to disperse to other MPAs, contributing to genetic connectivity and strengthening food webs and fisheries. Thus, the MPAs are linked by ecological corridors, and by assessing the overlay between larval settlement hot spots and MPA placement, the information contributes to indicators for system resilience and effectiveness (Watson et al. 2010; text adapted from Caselle et al. 2020). MPA placement on multiple sides of the archipelago may also contribute to resilience in the face of warming waters. As species ranges shift, aided by larval connectivity and due to warming ocean temperatures, MPAs located on the cooler west and south edges of islands may act as climate havens, given warming does not exceed species tolerances in those locations and cool, nutrient-rich upwelling and wind-driven mixing persists (Aristizabal et al. 2017). 

Figure 3. Map of the distribution of marine protected areas across the Northern Channel Islands archipelago, indicating jurisdictional ranges of state and federal institutions and the two types of protected areas (marine reserves and marine conservation areas) (PISCO).

Results

Following over a decade of protection, the Northern Channel Islands have seen success in MPA effectiveness. Studies show significant spillover of larval populations sourced from the MPAs dispersing and settling into the surrounding waters, indicating that the protected areas provide increased connectivity not only between MPAs within the network, but also beyond protection borders. In the first five years, densities of targeted fish species increased by 50 percent and biomass increased by 80 percent inside protected zones. More recently, protection of higher-level predators within older, fully protected areas has been shown to prevent invasion of a non-native macroalgae (Environment America). Success reached international renown when, in 2019, The Marine Conservation Institute and its international science council recognized the Northern Channel Islands MPAs as an outstanding MPA with a Blue Park designation, indicating that it holds the highest science-based standards for marine life protection and management. At the time, only 16 other MPAs worldwide earned the prestigious Blue Park Award (California Department of Fish and Wildlife). 

References

Aristizabal, M. F., M.R. Fewings, & L. Washburn. 2017. Effects of the relaxation of upwelling-favorable winds on the diurnal and semi-diurnal water temperature fluctuations in the Santa Barbara Channel, California. Journal of Geophysical Research: Oceans 122: 7958–7977. 

California Department of Fish and Wildlife. 2019. Northern Channel Islands Marine Protected Areas Join Growing Network of Global Ocean Refuges. Marine Management News.

Caselle, J., Carr, M., and White, J.W. 2020. Northern Channel Islands: Connectivity across a network of marine protected areas contributes to positive population and ecosystem consequences.

Environment America. 2021. California’s marine protected areas are working. 

Fractracker. Oil and Gas Activity by State.

NOAA. National Marine Sanctuaries. Climate Change and Ocean Acidification. Channel Islands.

The Partnership for Interdisciplinary Studies of Coastal Oceans (PISCO). A Decade of Protection; 10 Years of Change at the Channel Islands.

Watson, J.R., Mitarai, S., Siegel, D.A., Caselle, J.E., Dong, C., and McWilliams, J.C. 2010. Realized and potential larval connectivity in the Southern California Bight. Marine Ecology Progress Series 401:31–48.