Improving Marine Reserves

By Mary Trainor,
Marine conservation student

It is a wonderful sign of the times that governments around the world are taking action to protect the ocean.  One popular marine management tool is the marine protected area (MPA), which aims to conserve marine life and habitats by restricting what people can do within designated MPA boundaries (National Ocean Service 2012b).  There have recently been advancements in both the placement and abundance of state government regulated MPAs in United States waters.  For instance, in June of 2012,  the California Fish and Game Commission approved plans to implement the final 19 MPAs needed to complete the open-coast section of California’s Marine Life Protection Act, boosting California’s total MPA count to 119 (California Dept. of Fish and Game 2012).  In addition, the Florida Keys National Marine Sanctuary Advisory Council is currently re-evaluating the sanctuary’s boundaries and regulations in order to reflect changes in laws and scientific literature (National Ocean Service 2012a).

Corals are some of the many organisms protected by the Florida Keys National Marine Sanctuary. Source:

Corals are some of the many organisms protected by the Florida Keys National Marine Sanctuary. Source:


MPAs are also used in other parts of the world. When the European Union implemented the Marine Strategy Framework Directive (MSFD) in 2008, it required networks of MPAs to be placed throughout European waters in order to attain “Good Environmental Status” by 2020 (European Commission 2012). In 2008, European waters already contained MPAs, but no clear plan existed for further MPA development or improvement. Additionally, there was no cohesive body of information for use in assessing the efficacy of present or proposed reserves. With this in mind, Phillip B. Fenberg, Ph.D, and his colleagues published “The science of European marine reserves: Status, efficacy, and future needs” in March of 2012.
The objective of “The science of European marine reserves” is to help the European Union meet MSFD’s goal by providing a comprehensive overview of the conditions and impacts of European MPAs. This paper is highly significant because it summarizes the factors that contribute to MPA success, which can be directly applied to the development of future MPAs worldwide. According to the Fenberg et al. 2012 publication, a successful or effective MPA is one that contributes to marine conservation, often by assisting in the recovery of an overexploited species or habitat. The authors analyzed scientific literature, government documents, and existing surveys of marine scientists to determine the size and status of European marine reserves (a type of MPA which does not allow any removal of marine species), the impact of reserves on organisms and habitats, and the characteristics shared among successful reserves.
The authors found that, while there are currently 799 MPAs in European waters, there are only 74 fully no-take marine reserves. The vast majority of these marine reserves are small (less than 50 km2) and are located within larger MPAs in the Mediterranean Sea. Unfortunately, only 0.4% of the Mediterranean Sea is covered by MPAs that are actually enforced; Pelagos Sanctuary, which accounts for 90% of the area covered by Mediterranean MPAs, is only a “paper park,” meaning its rules are not enforced and so the area is treated as if it were not protected. Furthermore, two experimental Swedish reserves, which jointly contain 74% of protected area outside of the Mediterranean, are scheduled for evaluation soon. If these reserve protections are lifted, the majority of presently protected waters outside the Mediterranean will be exposed.

To assess the impact of reserves on density, biomass, organism size, and species richness, the authors used primary literature that contained quantitative data about one or more of those variables from both inside and outside the reserve. Fenberg et al. (2012) found that most of the reserves in the dataset are located in the Mediterranean Sea, which creates a geographical bias. However, the authors state that, since the vast majority of European marine reserves are also located in the Mediterranean, the data distribution is reasonably representative of all European reserves. Next, the authors calculated response ratios to compare data from inside and outside the reserves. They found that the marine reserves in the study not only resulted in significant increases in all the biological variables studied, but also initiated shifts in community structure that returned ecosystems to their natural states found under unfished conditions (i.e. moving from macroalgal forests to coral communities). These results are encouraging because they indicate that marine reserves can help overexploited species and habitats recover. What’s more, the profits of some of the Mediterranean marine reserves extend beyond their boarders in a phenomenon called “spillover.” When spillover occurs, adult animals move beyond the boundaries of the marine reserve, increasing the abundance and biomass of these species outside of protected areas and ultimately benefiting fishermen. The authors cite the Columbretes Reserve as a prime example of spillover. About 7% of the lobsters in this reserve migrate beyond reserve boundaries every year and contribute 31-43% of the weight of the commercial fishing catch in the Mediterranean.

European spiny lobster populations “spill-over” the boundaries of Mediterranean marine reserves and contribute to commercial fishing catch.  Source:

European spiny lobster populations “spill-over” the boundaries of Mediterranean marine reserves and contribute to commercial fishing catch. Source:


While it has been clear for some time that marine reserves can be effective tools for conservation, scientists are still determining the factors that are responsible for reserve success. Fenberg et al. (2012) contend that a portion of reserve efficacy depends on diligent enforcement. Surveillance is crucial to proper enforcement, but the cooperation of local communities is also helpful. Ideally, the government and the public would work together to eliminate ineffective “paper parks,” which are prevalent in European waters. Since enforcement ends at the reserve boundaries, the authors note that it is important to consider human activities like overfishing that occur outside of the reserve but can still impact reserve efficacy.

Lastly, Fenberg et al. (2012) emphasize that one of the most important factors in creating successful marine reserves is that they be located within an ecologically connected network of MPAs. Simply establishing reserves close to one another is not sufficient. Instead, reserves must be developed with the ecology of the ocean in mind so they protect target species throughout their lifecycles. To facilitate this plan, the authors call for continued extensive research exploring marine population structure and ecology, as well as quantifying the impacts of existing MPAs. “The science of European marine reserves” concludes by stating that while marine reserves are not specifically required by the MSFD (only MPAs are mandatory), properly establishing and managing marine reserves within a network of ecologically connected MPAs will greatly assist in attaining the MSFD goal to achieve “Good Environmental Status” by 2020.
This publication is an important step in enhancing marine conservation because it not only assesses the efficacy of current marine reserves, but, perhaps more importantly, it also presents ideas about what factors are responsible for reserve success. While this paper focuses on European marine reserves, its conclusions can be applied to MPA development worldwide. For example, the authors’ suggestions could be helpful to the professionals on the Florida Keys National Marine Sanctuary Advisory Council currently reassessing their own sanctuary’s design. By considering life history traits of target species, ensuring proper enforcement, and locating reserves within an ecologically connected network, scientists and government officials all over the world can optimize marine reserves to better protect our oceans.


California Department of Fish and Game (2012) Accessed 1 Nov. 2012.
European Commission (2012) European Commission – Environment. Accessed 1 Nov. 2012.
Fenberg P, Caselle J, Claudet J, Clemence M, et al. (2012) The science of European marine reserves:
status, efficacy, and future needs. Mar. Policy 36:1012-021
National Ocean Service (2012)a Florida Keys National Marine Sanctuary. Accessed 1 Nov. 2012.
National Ocean Service (2012)b National Marine Protected Areas Center. Accessed 1 Nov. 2012.

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