Effectiveness of MPA’s

By: Peter Aronson, SRC Intern

One might think that setting aside marine protected areas (MPA’s) – areas of the ocean where human activity is more heavily restricted – would reduce fishing pressure and overexploitation of marine species. However, that is not always the case. A group of researchers sought to determine if MPA’s experience intense human pressure, and if that pressure was undermining the goal of conserving biodiversity. They focused on European waters, where a substantial amount of industrial fishing occurs (Kroodsma et al., 2018), and an ample network of MPA’s covers about 29% of the sea (European Union, 2016).

Trawling is the most common method of industrial fishing in Europe (Kroodsma et al., 2018). It often has high bycatch rates and is a threat to many endangered species, including many elasmobranchs, as well as entire seafloor habitats. Researchers used satellite data to track fishing vessels and quantify commercial trawling effort. All 727 MPA’s in the study were considered 100% marine, designated prior to 2017, and listed on the World Database on Protected Areas.

Figure 1. Miramare Marine Reserve, Italy. (Sebastian Lake, September 29, 2015. Wiki Commons)

In 2017, combined trawling effort exceeded 1 million hours with over 225,000 occurring inside MPA’s. Trawling intensity, measured in hours per square kilometer, was 38% greater inside MPA’s compared to unprotected areas, and 46% more intense inside MPA’s when only looking at the areas that were trawled. This suggests that under current management, there is no reduction of fishing pressure inside MPA’s. Higher trawling rates typically occurred in larger MPA’s. Of all 727 MPA’s, trawling occurred in 489, of which 58% were located within territorial waters. Interestingly, only 40% of untrawled MPA’s had management plans whilst 60% of commercially trawled MPA’s did.

The relative abundance of 20 elasmobranch species was estimated from data collected on scientific trawl surveys between 1997 and 2016. Elasmobranchs were generally rare, with the main concentrations located west and south of the British Isles. Elasmobranchs were caught in 79% of the 178 MPA’s that were surveyed (only 13% of these had no commercial trawling). Total elasmobranch catch per research haul was 2.3 times higher outside MPA’s than inside, and a normalizing for species showed 24% more elasmobranchs outside the MPA’s.

Figure 2. Salmon shark caught in a trawl net. (Kathy Hough, Wiki Commons.)

Multiple factors are thought to drive conservation outcomes inside MPA’s, however, under present fishing pressure, only MPA size correlated positively with relative elasmobranch abundance. Untrawled MPA’s had a larger average elasmobranch abundance than trawled MPA’s. Overall, elasmobranch abundance negatively correlated with commercial trawling intensity both inside and outside MPA’s. It was found that commercial trawling was the strongest predictor of relative elasmobranch abundance across the study sites with an average decrease of 69% across the observed gradient of trawling intensity. This provides further evidence that increased trawling effort in MPA’s negatively impacts sensitive species and reduces ecological value.

This study shows designating MPA’s does little value for at-risk species. The issue of declining biodiversity due to high trawling intensity in European MPA’s has been highlighted here. The lack of international MPA standards may play a role in the lack of effectiveness, and better standardization of MPA’s should occur to avoid this. Allowing industrial fishing in MPA’s provides a false sense of security about marine conservation in Europe, and much work needs to be done to make MPA regulations stronger and management more transparent.

Work Cited:

A. Kroodsma et al., Science 359, 904-908 (2018). European Union, The EU in the World 2016 Edition (European Union, 2016).

Marine Protected Area (MPA) Effectiveness

By: Olivia Wigon, SRC Intern

Marine Protected Areas (MPAs) encompass any and every type of area in the oceans, seas, lakes or estuaries. MPAs have some type of restriction on human behavior and activity in an area with the intention to conserve natural resources in that area. MPAs not only protect animals but the economy through tourism and fishing. Divers and other ocean lovers will travel to see marine protected areas because of the large animals and the amount of life in them which stimulates the local economy. MPAs also help fishermen because the fish have time to grow and reproduce providing fishermen with sustainable amount of large fish to catch when the fish leave the MPA. While there has been an increase in MPAs, there are still challenges in determining the social and economic benefits of them (Edgar et al. 2014). Graham J. Edgar and his team looked at 87 MPAs located all around the world and found that they are most successful when there are 5 key features. The 5 features are well enforced, no take, isolated by deep water or sand, are older than 10 years, and are larger than 100 square kilometers. An effective MPA has twice as many large fish, five times more large fish biomass, and fourteen times more shark biomass than in unprotected areas (Edgar et al. 2014). Unfortunately, Graham J. Edgar and his team found that only 41% of MPAs studied had 3 or more of these key features. It is important to note that each MPA is different and is designed with different circumstances in mind. For example, an MPA may be designed for a specific species in mind, or for a specific time of year.

Globally shark populations are struggling due to over fishing, climate change, and shark finning. Additionally, shark populations take years to recover because they are k-selected species which means they have long life spans, few offspring and late sexual maturity. Humans are also k-selected animals. This has resulting in urgent conservation effort, including establishing marine protected areas in various shark habitats. Many species of sharks are pelagic which means that they travel great distances in the open ocean. Conservation for pelagic species is difficult because they are constantly moving so they will be protected in one area but as soon as they swim out of the MPA it is at risk again. In order to understand how MPAs protect sharks Danielle M. Knip and her team used acoustic tags and receivers around the Great Barrier Reef Marine Park in Australia. Both juvenile pigeye and adult spot-tail sharks were given acoustic tags. The juvenile pigeye sharks were found to spend more time in the MPAs during the summer and the adult spot-tails spent more time there in the winter (Knip et al. 2012). The MPAs in this study were shown to be effective because they protect multiple species, at various life stages, during various times of the year. Knips team also looked at how often sharks were leaving the marine protected area and where they were exiting and entering the MPAs. While the MPAs studied were not specifically designed for shark conservation they are aiding in the efforts to protect shark populations.

Conrad W. Speed and his team looked at how long it takes a shark population to rebound after exploitation and how the establishment of MPAs helps the recovery process (Speed et al. 2018). The team used baited remote underwater video stations (BRUVS) which are essentially a camera attached to a bait box which allows researchers to see what animals live in the area and how many of them there are. The team collected data both before and after several years of strict MPA enforcement. The MPAs the team looked at were well-managed and were no-take zones which means that nothing could be caught or removed from that area. Speed and the team saw a significant increase in apex species, and reef shark populations. Similar results were found amongst all the MPAs that were studied. Overall, the data shows that when marine protected areas are established and enforced for a significant amount they are effective in regards to an increase in fish biomass and an increase in shark populations. As the environmental movement grows there is becoming a greater demand for the creation of new marine protected areas and better management of those already established.

Work Cited:

Edgar, Graham J., et al. (2014) “Global Conservation Outcomes Depend on Marine Protected Areas with Five Key Features.” Nature, vol. 506, no. 7487, pp. 216–220., doi:10.1038/nature13022.

Knip, Danielle M., et al. (2012) “Evaluating Marine Protected Areas for the Conservation of Tropical Coastal Sharks.” Biological Conservation, vol. 148, no. 1, pp. 200–209., doi:10.1016/j.biocon.2012.01.008.

Speed, Conrad W., et al. (2018) “Evidence for Rapid Recovery of Shark Populations within a Coral Reef Marine Protected Area.” Biological Conservation, vol. 220, pp. 308–319., doi:10.1016/j.biocon.2018.01.010.

How the complexity of the average marine organism life cycle affects MPA efficiency

By Elana Rusnak, SRC masters student

Marine Protected Areas, or MPAs, are the global “National Park System” of the ocean.  There are a variety of protection levels, ranging from multi-use zones where certain activities may only be restricted seasonally, to no take-zones where only non-extractive activities are permitted (i.e. SCUBA diving and mooring a boat), and no-use zones, where there are no activities permitted (, 2015).  They are designed to protect a geographic area whose boundaries encompass everything from the surface of the ocean to the ocean floor, and all organisms that live within its borders.  MPAs are theoretically designed to protect ecosystem structure, function, and integrity, enhance non-consumptive opportunities, improve fisheries, and expand knowledge and understanding of marine systems (Stoner et al., 2012).  These jurisdictions are often put in place to protect the habitat of a certain target species, but yield an additional benefit wherein all of the other organisms that live in that species’ habitat are also protected, as long as they stay within the bounds.  For example, a study by Bond et al. in 2017 showed that the establishment of a marine reserve in Belize helped a Caribbean Reef Shark population go from declining (caused by overfishing), to stable over the course of roughly 10 years.

In terrestrial environments, National Parks/Reserves often encompass the entire geographic distribution of a target species.  For example, Yellowstone National Park was used in 1995 to reintroduce the Gray Wolf (Canis lupis) back into the wild, after being hunted nearly to extinction (Philips & Smith, 1997).  They generally live their entire lives within the park, and as such, their population grew to a sustainable level, and they were subsequently taken off the US Endangered Species List in 2008 (USFWS, 2008).

A Map of the various wolf packs within Yellowstone National park, by Yellowstone_wolfmap.jpg: work of a National Park Service employeederivative work: Rrburke (talk) – Yellowstone_wolfmap.jpg, Public Domain,

Unfortunately, success stories of this magnitude are not often seen in the marine environment for a few different reasons:  MPAs are more difficult to enforce, as they are in a 3D environment where depth is a factor.  This is amplified by the fact that many MPAs are created in countries without the resources to maintain them properly (Bennet & Dearden, 2014).  Moreover, the ocean is an ever-changing environment, with water flow and fluid dynamics having major effects on every ecosystem.  Additionally, a key factor that influences MPA efficacy is the unique life cycle of most marine organisms.  A fundamental difference between organisms on land, and in the ocean, is that marine organisms have larval stages.  Most fish and other marine organisms (corals, invertebrates, etc.) do not give live birth, or hatch their eggs in a stable environment like land animals.  Instead, many reproduce by spawning, which is releasing their millions of eggs and sperm into the water column in hopes they will connect with each other.  Once the eggs are fertilized and the larvae begin developing, they are subject to the forces of nature, and move wherever the current takes them.  They are also more or less microscopic at this point, and are often a food source for larger fish.  Because of this, the larvae of a tuna or blue marlin could be eaten by the very fish that they themselves prey on.  This unique circular pattern, coupled with the fact that larval dispersal can span hundreds of miles in the ocean, makes completely protecting a species in a single MPA very challenging (Cowen et al., 2006).

Queen Conch (Lobatus gigas) by Daniel Neal from Sacramento, CA, US – CC BY 2.0,

According to a study by Cowen et al. in 2006, larval dispersion of coral is affected by many factors, including how long the larvae stay in the water column before attaching to the substrate, directed horizontal/vertical movement of the larvae in the water column, and the adult spawning strategies themselves.  All of these put together result in larval dispersal distances of anywhere from 10-100km.  This dispersal is also seen in the endangered Queen Conch (Lobatus gigas) in the Bahamas.  The Exuma Cays Land and Sea Park is an MPA in the Bahamas, and there is a conch population inside the park that has been shown to be slowly dying of old age. This can be attributed to the fact that larvae are not making it into the park because the population that would be supplying them with larvae is outside of the protected area and is being overfished (Stoner et al, 2012; Kough et al. 2017).  The MPA does not cover the entire geographic distribution of the conch, and therefore, it can be seen that this life-cycle complexity is affecting the efficacy of this protected area.  There have been proposals to create MPA-networks that would protect multiple populations, which may increase larval recruitment (larvae reaching an area and settling down there) and consequently, target species survival.  All of this is evidence that shows we need to approach protecting terrestrial and marine species from different angles, since ecosystem type is clearly not the only fundamental difference between them.



Bennett, N. J., & Dearden, P. (2014). Why local people do not support conservation: community perceptions of marine protected area livelihood impacts, governance and management in Thailand. Marine Policy44, 107-116.

Bond, M. E., Valentin-Albanese, J., Babcock, E. A., Abercrombie, D., Lamb, N. F., Miranda, A., … & Chapman, D. D. (2017). Abundance and size structure of a reef shark population within a marine reserve has remained stable for more than a decade. Marine Ecology Progress Series576, 1-10.

Cowen, R. K., Paris, C. B., & Srinivasan, A. (2006). Scaling of connectivity in marine populations. Science311(5760), 522-527.

Kough, A. S., Cronin, H., Skubel, R., Belak, C. A., & Stoner, A. W. (2017). Efficacy of an established marine protected area at sustaining a queen conch Lobatus gigas population during three decades of monitoring. Marine Ecology Progress Series573, 177-189.

Philips, M. K., Smith, D. W. (1997).  Yellowstone Wolf Project – Biennial Report (1995-1996). National Park service., 2015.  Marine Managed Areas: What, Why, and Where. Science to Action.

Stoner, A. W., Davis, M. H., & Booker, C. J. (2012). Abundance and population structure of queen conch inside and outside a marine protected area: repeat surveys show significant declines. Marine Ecology Progress Series460, 101-114.

United States Fish and Wildlife Service, 2008.  “Species Profile – Gray Wolf.

Great Barrier Reef No-Take Areas Include a Range of Disturbance Regimes

By Shubham Mathur, SRC Intern

Figure 1: Zoning map for the Cairns area within the Great Barrier Reef Marine Park describing different zoning designations. The Inset map provides a reference to the location of the region in a broader scale.

Figure 1: Zoning map for the Cairns area within the Great Barrier Reef Marine Park describing different zoning designations. The Inset map provides a reference to the location of the region in a broader scale.

The zoning of marine protected areas and reserves that prohibit or reduce human activity is a common example of spatial management used to protect natural assets for current and future benefit. Both the distribution and size of the protected areas are crucial factors in their effectiveness. Marine spatial planning (MSP) is crucial for developing effective protections, taking a number of factors into account including current and predicted future patterns of use, the habitat condition, how well represented the habitat already is in marine protected areas, and key ecological processes such as larval connectivity. The Great Barrier Reef Marine Park off the coast of Eastern Australia is considered to be a global icon of marine ecosystem management. The Marine Park was rezoned in 2004 in order to increase the reach and effectiveness of no take areas over the park. An expert focus group suggested that a minimum of 20% of the Marine Park should be protected by no take areas. This incorporated events such as cyclones, pollution, climate change, and other major disturbances into account. At the time, limited data did not allow re zoning to take into account variation in exposure of the reefs to disturbances. The Great Barrier Reef Marine Park should have management objectives should incorporate aspects of dynamic phenomena. For the purposes of this study, four coral mortality causing disturbances were studied in the context of special patterns of exposure. These disturbances are mass bleaching events, cyclones, crown of thorns starfish, and low salinity.

Figure 2: (A) Thermal stress related coral bleaching (B) Damage caused by cyclone waves (C) Damage caused by crown of thorns starfish outbreaks (D) Damage resulting from excessive freshwater inundation

Figure 2: (A) Thermal stress related coral bleaching (B) Damage caused by cyclone waves (C) Damage caused by crown of thorns starfish outbreaks (D) Damage resulting from excessive freshwater inundation

The researchers gathered data on the four harmful disturbances found on the reef, collecting information regarding bleaching level thermal stress from 1982 to 2012, damaging waves from cyclones from 1985 to 2014, crown of thorns starfish outbreaks from 1982 to 2014, and freshwater inundation from 2001to 2011. The values for different levels of exposure for each disturbance were standardized, resulting in a scale from 0 to 1, where lower values indicate lower exposure, and higher values indicate higher exposure. Relative exposure was assessed by finding the mean scores of all four disturbances across the surveyed areas.

The relative exposure of the reef to bleaching resultant thermal stresses was relatively high for a little over 20 percent of the reef area, while a little over 30 percent of the reef area experienced a low exposure to thermal stresses. Similarly, approximately 20% of the reef experienced a high exposure to damaging waves from cyclones, and a little under 30% experienced low exposure. High exposure to the crown of thorns starfish was much more limited, at about 14% of the reef area, and 96% of the reef experienced no exposure to freshwater inundation. Only about 0.1% of the reef remained disturbance free for the duration of the surveys.

The analysis showed that even in no take areas, much of the reef suffered from one or more examples of harmful disturbances. This conclusion indicates that one of the most helpful things to do, would be to employ extra protections on the regions that did not experience any of the disturbances. Vulnerability for the different regions of the reef can be calculated by factoring exposure and sensitivity, along with the adaptive capacity of the area. A strong understanding of resilience and exposure allows for adaptive, resilience based management to maximize their benefits to the reefs, ensuring the future health and survival of the reef environments.


Maynard, J. A., Beeden, R., Puotinen, M., Johnson, J. E., Marshall, P., Hooidonk, R., … & Ban, N. (2015). Great Barrier Reef no‐take areas include a range of disturbance regimes. Conservation Letters.

Can Marine Protected Areas Help Conserve Intertidal Species?

By Hannah Calich, RJD Graduate Student

The giant limpet (Patella ferruginea; Figure 1) is one of the most endangered species in the Mediterranean Sea. As with many other marine species, their population decline has been attributed to overexploitation by humans. Giant limpets are most commonly harvested for food, fishing bait, or shell collection.

A giant limpet. Photo by: Jan Delsing / Wikipedia Commons

A giant limpet. Photo by: Jan Delsing / Wikipedia Commons

Much of the giant limpet’s remaining population is found within Sardinia’s marine protected areas (MPAs) and national parks. The population found within the Penisola del Sinis – Isola di Mal di Ventre MPA, is particularly important because despite being home to only a few hundred individuals this population has strong genetic differentiation, which is important for population recovery.

Unfortunately, giant limpets are being illegally harvested from within the Penisola del Sinis – Isola di Mal di Ventre MPA. In light of this finding, Coppa et al. (2015) set out to determine how much protection MPAs provide for intertidal species. Specifically, Coppa et al. (2015) investigated how site accessibility (semi-accessible vs. hardly accessible) and legal protection (high, medium, and limited protection) impact poaching levels and population size of the giant limpet within the Penisola del Sinis – Isola di Mal di Ventre MPA (Figure 2).

Map of Penisola del Sinis - Isola di Mal di Ventre MPA that highlights accessibility levels and protection zones. Zones A, B, and C have high, medium, and limited legal protection, respectively. Figure from Coppa et al. (2015)

Map of Penisola del Sinis – Isola di Mal di Ventre MPA that highlights accessibility levels and protection zones. Zones A, B, and C have high, medium, and limited legal protection, respectively. Figure from Coppa et al. (2015)

Figure 2b

The results of annual field surveys in 2011 and 2013 showed that the total population of giant limpets has declined 52% in two years as a result of illegal harvesting. However, this decline was not consistent throughout the MPA. There was a significantly higher density of giant limpets in hardly accessible sites compared to easily accessed sites. Additionally larger individuals, which are targeted by poachers, were predominantly found in sites with maximum legal protection that were hard to access. If the current levels of illegal harvesting continue the authors predict that the giant limpet may face local extinction within the next 10 years. These results suggest that this MPA is only protecting limpets in certain areas and unfortunately, this protection is insufficient.


Local people collecting intertidal invertebrates within Penisola del Sinis - Isola di Mal di Ventre MPA. Photo from Coppa et al. (2015)

Local people collecting intertidal invertebrates within Penisola del Sinis – Isola di Mal di Ventre MPA. Photo from Coppa et al. (2015)

The results of this study emphasize the fact that simply implementing an MPA is not necessarily sufficient to ensure species protection. This is particularly true for intertidal species that are easily accessed by illegal harvesters. Coppa et al. (2015) suggest that joint efforts between enforcement agencies, regulators, and researchers are a crucial component to ensure MPAs are able to meet their conservation objectives.



Coppa, S., De Lucia, G. A., Massaro, G., Camedda, A., Marra, S., Magni, P., Perilli, A., Di Bitetto, M., Garcia-Gomez, J. C., Espinosa, F. (2015). Is the establishment of MPAs enough to preserve endangered intertidal species? The case of Patella ferruginea in Mal di Ventre Island (W Sardinia, Italy). Aquatic Conservation Marine and Freshwater Ecosystems. DOI: 10.1002/aqc.2579



Fishermen Views on Marine Protected Areas

By Alice Schreiber, RJD Intern

As fish stocks continue to decline, Marine Protected Areas are becoming increasingly popular methods of conserving marine habitats and preserving species. The success of these areas depends upon the existing legal framework, acceptance by the community, and an effective management system [1].

Image 2

Being aware of how fishermen socially perceive MPAs is crucial when establishing them and creating management guidelines. MPAs are established areas where fishing pressure is reduced by designating the amount of fishing effort, time available for fishing activity, species that can be caught, gear permitted, or catch limits [2]. At times, Marine Protected Areas may completely restrict fishing or some areas may be designated Marine Reserves which function as no-take zones. The expectation is that the MPA will “maintain or restore marine biodiversity and ecosystem function,” as well as “improve socioeconomic conditions by increasing revenues from fisheries production due to an increase in the size and number of fish migrating out of the MPA [3]”.  Without taking into account the stakeholders’ perception of the reserve, enforcing management of Marine Protected Areas would be nearly impossible.

A new study by Monalisa Silva and Priscila Lopez, sheds some light on how to determine fishermen’s perceptions of MPAs and what criteria influence the opinions the fishermen have about the MPA. When evaluating perception among fishers, four questions are asked: (1) if a fisherman born in a place subjected to the limitations of an MPA has a more conservationist attitude; (2) if young, part-time, non-selective fishers are more flexible and adaptable to changes in the reserves, (3) if full-time fishermen who were born in a community under the influence of an MPA have greater participation in the establishment of management; and (4) if fishermen born in a community under the influence of an MPA have more positive opinions than immigrant fishermen regarding the protected areas [2].

Asking these questions allows researchers and policy makers to understand which individuals within a community are less likely to comply with the regulations, and as such, which individuals would benefit from more education or incentives regarding the protected areas. Compliance will not be at adequate levels if there is not a proper understanding from the public of why MPAs are needed.

Three MPAs in the states of Rio Grande do Norte served as the location for the study, in which one hundred fishermen were interviewed. The fishermen were between the ages of 21 and 77 years old and had an average fishing experience of 29 years. They were split into four groups, depending on their age, birthplace, type of fishing gear, and their level of dependence on fishing. They then took a questionnaire, which assessed their perception of biodiversity conservation, flexibility and adaptability, participation in management, and opinions about MPAs.

Image 1

The results of this study were able to confirm that older fishermen using selective gear have a more conservationist perception, full-time fishermen who use selective gear have lower flexibility and adaptability, and older fishermen tend to have more positive opinions regarding the MPA [2]. Flexibility and adaptability are important in regards to MPA compliance. Selective fishing gear allows fishermen to target a specific species or size of fish and when that fish stock collapses or is not longer allowed to be fished, they have very little flexibility in their choices. Encouraging fishermen to work in other areas part-time or to explore different resources beyond fish may help to ease the lack of flexibility.

Taking into account stakeholder perception is extremely important for the proper and effective management of MPAs. Compliance issues result from misconceptions of the conservational goals and from heavy dependence on fishing as their primary or only income. Being considerate of these issues allows for more effective management of MPAs and a more positive perception from fishermen and the affected community.


Works Cited

Salm, Rodney V., John R. Clark, and Erkki Siirila. Marine and coastal protected areas: a guide for planners and managers. IUCN, 2000.

Silva, Monalisa RO, and Prisicla FM Lopes. “Each fisherman is different: Taking the environmental perception of small-scale fishermen into account to manage marine protected areas.” Marine Policy 51 (2015): 347-355.

Pomeroy, Robert S., et al. “How is your MPA doing? A methodology for evaluating the management effectiveness of marine protected areas.” Ocean & Coastal Management 48.7 (2005): 485-502.


Five Keys to Effective Marine Protected Areas

By Lindsay Jennings, RJD Intern

Marine Protected Areas, or MPAs, are areas of the ocean which have a degree of restricted human use for the purpose of protecting its natural resources as well as its ecosystem. Over the past years, the number of MPAs has grown rapidly as conservation efforts push the need for these critical refuges for vulnerable species. But the threat of overfishing still prevails in both coastal areas and in the open ocean, where these MPAs exist.

Picture 1

Salomon Atoll located in the Chagos Archipelago, the world’s largest marine reserve. Photo courtesy of Wikimedia Commons

Unfortunately, too often, MPAs fall short of reaching their full potential due to a host of problems including illegal harvesting, poor management, and the presence of animals which can move freely across the boundaries to be fished outside of the MPA. But Graham Edgar, from the University of Tasmania, along with 24 other researchers took on the first global study of its kind to identify what key factors produce effective MPAs and allow them to reach their full potential.

 The researchers, along with trained volunteer divers surveyed 964 sites across 87 established MPAs identifying the key indicators of healthy MPAs such as species richness (i.e. how many unique fish species are found) and biomass (i.e. the total number of fish in a survey site). They compared these sites with non-MPA sites that are open to fishing. The results highlight the magnitude of how fishing can affect these species and ecosystems.


Distribution of sites surveyed with colored circles representing NOELI features. Photo courtesy of Edgar et al., 2014

Outside of MPAs (areas where fishing is allowed), Edgar et al. found total fish abundance drastically reduced, with upwards of an 80% reduction in large fish, including sharks, groupers, and jacks as compared to fish abundance within the MPAs. Inside these protected MPAs, the number of unique fish species found was 36% greater than that outside the MPAs in fished waters.

The outcome of the MPAs investigated resulted in the researchers concluding that conservation benefits increased greatly with five key features, which they named NOELI features.

  • No take (no fishing or harvesting allowed)
  • Well-enforced
  • Old (>10 years)
  • Large (> 100 km)
  • Isolated

While not every MPA will meet all five criteria, it is crucial that future MPAs implement better design and management and compliance to ensure that these refuges achieve their full ecological potential and conservation value.

MPAs are remarkable conservation tools, if developed and managed properly. The researchers in this study stress that by removing the threat of fishing coupled with sufficient will among stakeholders, managers, and politicians, there can be increased levels of compliance, ultimately allowing the MPAs to reach their full conservation potential and fulfill their role of safeguarding populations of vulnerable species.

Can MPAs help tropical sharks?

By Christina Marmet,
Marine conservation student

Sharks have been around for 450 million years, and have survived every extinction episode that our Earth has known since then (Litman 1996). However, human beings may be the biggest threat they have ever faced.

Today, there are about 500 species of sharks in the ocean, with more being discovered regularly. However, according to the IUCN Red List, more than one-third of all oceanic shark species are at risk of extinction. They are endangered mostly because of overfishing and the increased loss and degradation of coastal habitats (Stevens et al. 2000, Ferretti et al. 2010).

One of many possible solutions to help protect sharks is to create marine protected areas (MPAs), especially in coastal areas where sharks are most vulnerable to human impacts. However, in most cases, lack of knowledge regarding the movement patterns of sharks hinders the establishment of specific shark protected areas.

The National Oceanic and Atmospheric Administration MPA Center defines marine protected areas as “any area of the marine environment that has been reserved by federal, state, territorial, tribal, or local laws or regulations to provide lasting protection for part or all of the natural and cultural resources therein” (NOAA MPA Center accessed Nov. 1, 2012).

Hypothetical example of a marine protected area, a marine reserve, and a no-take marine reserve. Source: Pacific Fishery Management Council (

Hypothetical example of a marine protected area, a marine reserve, and a no-take marine reserve. Source: Pacific Fishery Management Council (


MPAs are put in place mostly for the protection and conservation of rare and endangered marine species and habitats, as well as to maintain the biodiversity of a specific area (Agardy 1997). MPAs can also help preserve the socio-economic value of a marine area for human use through fisheries or recreation. They are thought to be most effective at protecting sedentary species – animals who have very little movement or are attached to something – as most MPAs are small in size, and the benefits from the protection diminishes once individuals move outside the boundaries (Bonfil 1999).

Many MPAs have been put in place without prior knowledge of how they will function due to the urgent need for protection of marine environments (Roberts, 2000). In Knip et al. (2012), the aim of the study was to evaluate the possible degree to which existing MPAs may shelter shark populations by tracking the movements of two tropical coastal species within two MPA regions in the Great Barrier Reef Marine Park, Australia. Their hypothesis was that coastal sharks received conservation benefits from the MPAs by staying inside the boundaries (Knip et al. 2012).
The research was conducted from 2009 to 2010 in Cleveland Bay, within which there are two Conservation Park (CP) zones with strict fishing restrictions (Knip et al. 2012). During the course of the study, 37 pigeye sharks (Carcharhinus amboinensis) and 20 spottail sharks (Carcharhinus sorrah) were fitted with acoustic transmitters. Receivers were deployed throughout the two CP zones to monitor shark movement and residency inside the MPA (Knip et al 2012).

Acoustic transmitters allow scientists to know the location of tagged animals and time at which they pass within the range of the receivers (Welch 2005). Downloading of receiver data occurred every 6-8 weeks (Knip et al. 2012). The acoustic receivers were placed only inside the CP zones. Consequently, the interval between all detections was calculated for each individual shark to determine the length of time outside the protected area. The scientists concluded that the longer the interval between detections, the more likely the shark had exited the MPA (Knip et al. 2012).
The acoustic tagging led to the findings that pigeye sharks spent a mean of 23% of their time inside the MPA, while spottail spent a mean of 32% (Knip et. Al 2012). They also discovered seasonal variations: pigeye sharks spent twice as long in the MPAs in summer than winter, and the opposite pattern was apparent among spottail sharks (Knip et al. 2012). All individuals made excursions outside of MPAs, but the number and duration of the excursions varied among individuals of both species (Knip et al. 2012).
The authors recognized that these results lead us to believe that these two species of sharks are beneficiaries of the marine protected areas. It undeniably shows a certain degree of protection for the sharks, as they were found spending a noteworthy amount of time in the MPAs. However, the percentages also show that the sharks are out of the reserve 70 to 80% of the time, suggesting that MPAs in this region provide only limited protections for these two species, and potentially for all mobile species.
Indeed, the authors suggested that the degree of MPA effectiveness would in part depend on the seasonality of the nearby fishery industry, with respect to the seasonality and timing of excursions of sharks from MPAs (Knip et al. 2012). It would have been interesting to look at precise bycatch data, such as how many fishermen incidentally catch and release sharks, and where and when exactly they catch them. The authors mention that the location where the sharks exit the MPAs is of critical importance for conservation. Most fishing effort in this region occurs in the intertidal zone, which is where the pigeye sharks prefer to cross out of the CP zones (Knip et al. 2012). The effects of fishing pressure were obvious: fishers in this region removed 21% of the pigeye shark population, while there was no capture of spottail sharks (Knip et al. 2012), thus suggesting the need for fisheries regulations in and around the MPAs. Unfortunately, there was no discussion of fishermen sample size, and it is thus hard to determine the significance of this catch, which may represent only a fraction of total fishing threat.
This paper demonstrates the importance of knowing the movement patterns of sharks and other mobile species in order to create better conservation areas. Undeniably, it would be worth spending more time looking at the reasons for the crossing patterns in and out of the MPAs for these two species of sharks. Besides, if the area adjacent to an MPA boundary is heavily fished, the risk of capture for an individual will remain high even if it spends most of its time inside the MPA (Knip et al. 2012).
This study was among the first to evaluate the efficacy of MPAs for shark conservation (Knip et al. 2012). Consequently, it proved that not only the creation of MPAs could be an important contributor to shark conservation, but also that better knowledge of shark behavior would most likely encourage the development of more specific and effective fisheries-management plans. The authors suggest an ‘onion-ring’ type approach to MPA design, where core areas would be buffered by outer zones that exclude potentially high impact fisheries (Knip et al. 2012). It can be concluded that the effectiveness of MPAs for sharks is dramatically decreased by certain fishing activities nearby, and that there is a need for better MPA regulations in and around protected areas.
The authors came to the conclusion that this study demonstrated that individual MPAs may generate benefits for multiple shark species, and thus did not need to follow a species specific initiative (Knip et al. 2012). Although this study demonstrates that MPAs are a good first step to protecting even highly mobile species, it is crucial to remember the great diversity of shark species. These findings can really only be generalized to other shark species with similar life history and behavioral characteristics. Consequently, more research into the potential for MPAs to contribute to shark conservation is needed in different ecosystems worldwide.


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Wildlife Extra News. 2008

Marine protected areas: a viable conservation approach for wide ranging species?

by Fiona Graham, RJD Intern

Marine protected areas (MPAs) are regions of the ocean that have been zoned off and designated a level of protection. Different levels of protection can be offered by these zones, for example a no take zone, where regulations in that area do not permit fishing of any kind. Another example is a research only area, where recreation and commercial activities are not allowed.

While MPAs are effective at employing ecosystem-based management as a conservation tool, these networks of protected zones must be carefully chosen. MPAs function best as a well-connected group of distinct patches (a spatial network), each working to supplement the benefits of another, rather than as independent zones. Therefore, strategic area placement and size is crucial for the best conservation outcome. MPAs operating as ecologically cohesive networks should perform a variety of functions, including interacting with and supporting the surrounding environment. They should also maintain the processes, functions and structures of the intended protected features across their natural range, and function synergistically as a whole, such that the individual protected sites are able to benefit from each other (Ardron et al. 2008).

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