Fish Biomass, Abundance and Diversity Increases in MPAs
Scientists have repeatedly shown that MPAs can rapidly increase the biomass and diversity of species in both tropical and temperate ecosystems serving as insurance policies against the impacts of fishing.
An overwhelming body of scientific theory and evidence from around the world indicates that effectively managed no-take marine reserves can reverse the effects of overfishing and destructive fishing methods (Lester et al., 2009). In highly protected, well-managed and enforced MPAs diversity and abundance of marine life increases. Fishes reproducing within these areas spill over into surrounding areas and positively benefit surrounding human communities (Gell and Roberts, 2003, Guidetti, 2007, Lester et al., 2009).
MPAs Protect from Climate Change Effects Such as Natural Disasters and Coral Disease
Coral reefs and mangrove forests act as a natural barriers from natural disasters. Coral reefs act like breakwaters breaking down the force of waves before they hit land, while mangrove forests act as shock-absorbers, absorbing extra wave energy. In addition, mangrove forests also buffer against coastal erosion, sequester carbon and filter terrestrial pollution. Protecting these marine ecosystems essentially protects the 3.5 billion people who live in coastal areas.
In a recent study by Lamb et al. 2015, Great Barrier Reef marine played a significant role in reducing the prevalence of coral disease. Coral diseases were found more often in reefs that were not protected, signifying that high levels of injured corals, from fishing and other activities, were more vulnerable to diseases.
MPAs Provide a Big Boost to Ocean Economies
A recent analysis commissioned by WWF on MPAs has shown that investing in the creation of MPAs is expected to triple benefits returned through factors such as fisheries, coastal protection and employment. “The report found that increased protection of critical habitats could result in net benefits of between US$490 billion and US$920 billion accruing over the period 2015-2050.”
These benefits have motivated a number of nations to set goals for MPA coverage of their ocean territories, and international bodies are working to establish MPAs on the high seas. Marine protected areas, if managed properly, can be an effective way of protecting marine ecosystems and their associated cultural and historical heritage for future generations to experience and enjoy.
Summary of MPA Benefits
Although there are many reasons MPA’s are important, some of the best reasons to support them are because:
Lynham J., Nikolaev A., Raynor J., Vilela, T. & Villaseñor-Derbez, J. C.. (2020)
Nature Communications, https://doi.org/10.1038/s41467-020-14588-3
We find that the monument expansions had little, if any, negative impacts on the fishing industry, corroborating ecological models that have predicted minimal impacts from closing large parts of the Pacific Ocean to fishing.
Stewart B. D., Howarth L. M., Wood H., Whiteside K., Carney W., Crimmins É., O’Leary B. C., Hawkins J. P., Roberts C. M. (2020)
Frontiers in Marine Science, https://doi.org/10.3389/fmars.2020.00076
Since protection, biodiversity has increased substantially, along with the size, age and density of commercially important species... Arguably more important, however, is the influence the Lamlash Bay NTZ and COAST have had on UK marine protection in general. Most notably, detailed research has created a case study that clearly demonstrates the benefits of protection in an area where little such evidence is available.
Edgar, G. J., , Ward, T.J., R. D. Stuart-Smith. (2018)
Aquatic Conservation doi.org/10.1002/aqc.2934.
The biomass of large fishes observed on underwater transects decreased significantly over the same period on fished reefs (36% decline) and in marine park zones that allow limited fishing (18% decline), but with a negligible overall change in no‐fishing marine reserves. Populations of exploited fishes generally rose within marine reserves and declined outside the reserves, whereas unexploited species showed little difference in population trends within or outside reserves.
Fidler R.Y., Carroll J., Rynerson K.W., Matthews D.F., Turingan R.G. (2018)
PLoS ONE 13(2): e0193426. https://doi.org/10.1371/journal.pone.0193426
Shifts toward advantageous phenotypes were most common in the oldest and largest MPAs, but occurred in all of the MPAs examined. These results suggest that MPAs may provide protection against the impacts of size-selective harvest on life-history traits in coral-reef fishes.
Mellin, C., Aaron MacNeil, M., Cheal, A. J., Emslie, M. J. and Julian Caley, M. (2016)
Ecol Lett. doi:10.1111/ele.12598
MPAs can increase the resilience of marine communities to natural disturbance possibly through herbivory, trophic cascades and portfolio effects.
Areas: Australia, Global
Advani, S., Rix, L. N., Aherne, D. M., Alwany, M. A. and Bailey, D. M. (2015)
PLoS One, 10(5), e0126098 DOI: 10.1371/journal.pone.0126098
Our findings indicate that due to non-compliance the no-take reserve is no longer functioning effectively, despite its apparent inital successes and instead a gradient of fishing pressure exists with distance from the nearest fishing community.
Caselle, J. E., Rassweiler, A., Hamilton, S.L. & Warner R.R. (2015)
Scientific Reports 5, Article number: 14102
We found that the biomass of targeted (i.e. fished) species has increased consistently inside all MPAs in the network, with an effect of geography on the strength of the response. More interesting, biomass of targeted fish species also increased outside MPAs, although only 27% as rapidly as in the protected areas, indicating that redistribution of fishing effort has not severely affected unprotected populations.
Emslie, M.J., Logan, M., Williamson, D. H., Ayling, A. M., MacNeil, A. M., Ceccarelli, D., Cheal, A. J., Evans, R. D., Johns, K. A., Jonker, M. J., Miller, I. R.,Osborne, K., Russ, G. R., Sweatman H. P. A. (2015)
Current Biology, 25, 1-10 DOI: 10.1016/j.cub.2015.01.073
NTMRs (Networks of no-take marine reserves) may provide greater potential for replenishment after disturbances.
Fernández- Chacón, A., Moland, E., Espeland, S. H., Olsen, E. M. (2015)
Appl Ecol 52: 1206-1215. doi: 10.1111/1365-2664.12477
MPAs that are no-take zones can increase survival, which may result in increases in population density and beneficial spill over to surrounding areas, and are likely to be most effective in areas where local populations are particulary reduced.
Areas: Flødevigen, MPA
Gurney, G. G., Pressey, R. L., Ban, N. C., Alvarez-Romero, J. G., Jupiter, S. and Adams, V. M. (2015)
Conservation Biology DOI: 10.1111/cobi.12514
The efficacy of protected areas varies, partly because socioeconomic factors are not sufficiently considered in planning and management.
Areas: Kubulau, Fiji
Howarth, L. M., Roberts, C.M., Hawkins, J.P., Steadman, D.J., & Beukers-Stewart, B. D. (2015)
Overall, this study is consistent with the hypothesis that marine reserves can encourage the recovery of seafloor habitats, which, in turn, can benefit populations of commercially exploited species, emphasising the importance of marine reserves in the ecosystem-based management of fisheries.
Lamb, J. B., Williamson, D. H., Russ, G. R. and Willis, B. L. (2015)
Ecological Society of America http://dx.doi.org/10.1890/14-1952.1
This is the first study to link disease with recreational use intensity in a park, emphasizing the need to evaluate the placement of closures and their direct relationship to ecosystem health. We found that sites located within reserves had four-fold reductions in coral disease prevalence compared to non-reserve sites (80,466 corals surveyed).
Solar, A. G., Edgar, J. G., Thomson, J. R., Kininmonth, S., Campbell, J. S., Dawson, P. T., et al. (2015)
PLoS ONE 10(10): e0140270 DOI: 10.1371/journal.pone.0140270
The biomass of all major trophic groups (higher carnivores, benthic carnivores, planktivores and harbivores) was significantly greater (by 40% - 200%) in effective no-take MPAs relative to fished open-access areas.
Devillers, R., Pressey, R. L., Grech, A., Kittinger, J. N., Edgar, G. J., Ward, T. and Watson, R. (2014)
Aquatic Conserv: Mar. Freshw. Ecosyst. doi: 10.1002/aqc.2445
A review of global MPAs highlighted a global pattern of established MPAs in areas of little consequence to existing human extractive use.
Areas: Great Barrier Reef
Edgar, G. J., R. D. Stuart-Smith, T. J.Willis, S. Kininmonth, S. C. Baker, S. Banks, N. S. Barrett, M. A. Becerro, A. T. F. Bernard, J. Berkhout, C. D. Buxton, S. J. Campbell, A. T. Cooper, M. Davey, S. C. Edgar, G. Försterra, D. E. Galván, A. J. Irigoyen, D. J. Kushner, R. Moura, P. E. Parnell, N. T. Shears, G. Soler, E. M. A. Strain & Russell J. Thomson. (2014)
Conservation benefits of 87 MPAs investigated worldwide increase exponentially with the accumulation of five key features: no take, well enforced, old (>10 years), large (>100 km2), and isolated by deep water or sand.
Olds, A. D., Pitt, K. A., Maxwell, P. S., Babcock, R. C., Rissik, D. and Connolly, R. M. (2014)
Global Change Biology. doi: 10.1111/gcb.12606
Marine reserves enhanced the capacity of coral reefs to withstand flood impacts. Reserve reefs resisted the impact of perturbation, whilst fished reefs did not. The capacity of reserves to mitigate external disturbances and promote ecological resilience will be critical to resisting an increased frequency of climate-related disturbance.
Pina-Amargos, F., Gonzalez-Sanson, G., Martin-Blanco, F. and Valdvivia, A. (2014)
Peer J 2:e274; DOI: 10.7717/peerj.274
Gardens of the Queen in Cuba, has had a positive effect on the abundance of commercially valuable reef fish species in relation to neighboring unprotected areas.
Rising, J.A. and G.M. Heal (2014)
SSRN 2380445 (2014)
60% of country regions currently have insufficient protected areas to generate economic benefits, where the average break-even point for economic benefits of MPAs is at 8.5% of marine area.
White C, Costello C (2014)
PLoS Biol 12(3): e1001826. doi:10.1371/journal.pbio.1001826
Proposal to close the high seas to fishing was analyzed using a bioeconomic model. Found that closing all high seas to fishing would give rise to large gains in fisheries profit,fisheries yields, and fish stock conservation.
Areas: High Seas
Goetz, J.S., and Fullwood, L.A.F. (2013)
Coral Reefs (2013) 32:121–125 DOI: 10.1007/s00338-012-0970-4
Marine reserves can benefit sharks by offering greater prey availability inside a protected reserve for better foraging and survival.
Areas: Namena reserve, Fiji
Harrison, H. B., Williamson, D. H., Evans, R. D., Almany, G. R., Thorrold, S. R., Russ, G. R., Feldheim, K.A., van Herwerden, L., Planes, S., Srinivasan, M., Berumen, M. L., and Jones, G. P. (2012)
Current Biology, 22(11), 1023-1028 DOI: 10.1016/j.cub.2012.04.008
Effective, no-take reserves can provide a significant amount of recruitment and contribute to the replenishment of populations at both reserved and fished sites on a scale benefiting local stakeholders
Micheli, F., Saenz-Arroyo, A., Greenley, A., Vazquez, L., Montes J.A.E., Rossetto, M., and De Leo, G. (2012)
PLoS ONE 7(7): e40832. DOI:10.1371/journal.pone.0040832
No-take marine reserves can support more resilient marine populations in the face of large scale environmental impacts compared to unprotected areas outside of a reserve.
Areas: Baja California, Mexico
Aburto-Oropeza, O., Erisman, B., Galland, G. R., Mascareñas-Osorio, I., Sala, E., and Ezcurra, E. (2011)
PLoS One, 6(8), e23601 DOI: 10.1371/journal.pone.0023601
Social and ecological factors can aid no-take marine reserves increase fish biomass as well as provide significant economic benefits to the surrounding community.
Howarth, L. M., Wood, H. L., Turner, A. P., & Beukers-Stewart, B. D. (2011)
Marine biology, 158(8), 1767-1780
This study investigated the effects of a fully protected marine reserve on commercially valuable scallops and benthic habitats in Lamlash Bay, Isle of Arran, United Kingdom. Dive surveys found the abundance of juvenile scallops to be greater within the marine reserve than outside.
Pelc, R. A., Warner, R. R., Gaines, S. D., Paris, C. B. (2010)
PNAS, 107 (43). 18266-18271 DOI: Biology, 25, 1-10 DOI: 10.1073/pnas.0907368107
Given the magnitude of increased production typically found in marine reserves, benefits from larval export are nearly always large enough to offset increased mortality outside reserves due to displaced fishing effort.
Areas: Model based
Pichegru, L., Grémillet, D., Crawford, R. J. M., and Ryan, P. G. (2010)
Biology Letters, 6(4), 498-501 DOI: 10.1098/rsbl.2009.0913
No-take marine reserves can immediately benefit marine top predators, like the African penguin that relies on pelagic prey, such as sardines and anchovies, by providing new and protected foraging areas.
Areas: South Africa
Cudney-Bueno, R., Lavin, M. F., Silvio, G. M., Raimondi, P. T. and Shaw, W. W. (2009)
PLoS ONE 4(1): e4140. doi:10.1371/journal.pone. 0004140
Enhancement occurred rapidly (2yrs), with up to a three-fold increase in density juveniles found in fished areas at the downstream edge of the reserve network, but other fishing areas within the network were unaffected
Areas: Gulf of California, Mexico
Lester, S.E., B.S. Halpern, K. Grorud-Colvert, J. Lubchenco, B.I. Ruttenberg, S.D. Gaines, S. Airamé and R. R. Warner. (2009)
Marine Ecology Progress Series 384: 33–46.
Reserve characteristics and context, particular the intensity of fishing outside the reserve and inside the reserve before implementation, play key roles in determining the direction and magnitude of the reserve response and protection.
Stockwell, B., Jadloc, C.R.L., Abesamis, R.A., Alcala, A.C., and Russ, G.R. (2009)
Marine Ecology Progress Series, 389, 1-15 DOI: 10.3354/meps08150
Protection of functionally important fish, such as parrotfish, can lead to decreased algal growth and ultimately increased coral cover and abundance.
Claudet, J., Osenberg, C. W., Benedetti-Cecchi, L., Domenici, P., García-Charton, J.-A., Pérez-Ruzafa, Á., Badalamenti, F., Bayle-Sempere, J., Brito, A., Bulleri, F., Culioli, J.-M., Dimech, M., Falcón, J. M., Guala, I., Milazzo, M., Sánchez-Meca, J., Somerfield, P. J., Stobart, B., Vandeperre, F., Valle, C. and Planes, S. (2008)
Ecology Letters, 11: 481–489. doi: 10.1111/j.1461-0248.2008.01166.x
Reserve size and age do matter: Increasing the size of the no-take zone increases the density of commercial fishes within the reserve compared with outside; whereas the size of the buffer zone has the opposite effect.
Russ, G. R., Cheal, A. J., Dolman, A. M., Emslie, M. J., Evans, R. D., Miller, I., Sweatman, H., and Williamson, D. H. (2008)
Current Biology, 18(12), R514-R515 DOI: 10.1016/j.cub.2008.04.016
Densities of primary fisheries targets, like coral trout in the Great Barrier Reef, significantly increased in just two years due to a no-take management approach vs. in areas where fishing was allowed
Sweatman, H. (2008).
Current Biology, 18(14), R598-R599 DOI: 10.1016/j.cub.2008.05.033
Protection from fishing can have a positive effect on reducing the frequency of outbreaks of the predatory crown-of-thorns starfish. Outbreaks were found to be 7 times lower inside no-take areas vs reefs open to fishing
White C, Kendall, B. E., Gaines, S., Siegel, D. A. and Costello C (2008)
Ecology Letters 11(4): 370-379 doi: 10.11111/j.1461-0248.2007.01151.x
Our results indicate that reserves can still benefit fisheries, even those targeting species that are expensive to harvest. Furthermore, reserve area and harvest intensity can be traded off with little impact on profits, allowing for management flexibility while still providing higher profit than attainable under conventional management
Leisher, C.D., van Beukering, P., and Scherl, L.M. (2007)
Report to the Nature Conservancy, the Australia Government Department of the Environment and Water Resources, and the Poverty Reduction and Environment Management Program at Vrije Universiteit in Amsterdam
Marine protected areas can effectively contribute to poverty reduction by improving fish catches via ‘spillover,’ establishing new jobs in the tourism sector, better health and nutrition from increased protein, and better local governance of reserve management.
Abesamis, R.S., Russ, G.R., Alcala, A.C. (2006)
Aquat Conserv 16:349-371
Apo Reserve had a gradient of abundance of target fish across at least one boundary, a result consistent with spillover.
Areas: Apo Island, Philippines
Shears, N. T., Grace, R. V., Usmar, N. R., Kerr, V., & Babcock, R. C. (2006)
Biological Conservation, 132(2), 222-231
In assessing the efficacy of a no-take vs. partial protection marine reserve, spiny lobster were found to be 11 times more abundant and have 25 times higher biomass than those spiny lobster in the partially-protected marine reserve.
Abesamis, R.S., Russ, G.R. (2005)
Ecol Appl 15: 1798-1812
Both density and modal size increased outside the reserve close to 200-300m), but not father from (300-500m), the reserve boundary over the 20 years of reserve protection.
Areas: Apo Island, Philippines
Alcala, A.C., Russ, G.R., Maypa, A.P., Calumpong, H.P. (2005)
Can J Fish Aquat Sci 62:98-108
These experiments, plus spillover evidence, suggest that marine reserves may help maintain, or even enahnce, local fishery yields in the long-term.
Beukers-Stewart, B. D., Vause, B. J., Mosley, M. W. J., Rossetti, H. L. and Brand, A. R. (2005)
Marine Ecology Progress Series 298:189-204
These patterns of scallop density, age and size structure resulted in the exploitable biomass of scallops being nearly 11 times higher in the closed area than in the fished area by 2003, and the reproductive biomass was 12.5 times higher
Areas: Isle of Man, United Kingdom
Denny, C. M., Willis, T. J., & Babcock, R. C. (2004).
Marine Ecology Progress Series, 272, 183-190.
Post-establishment of a no-take status, snapper populations showed significant increases in abundance (7.4 times higher), biomass (818% higher), and fecundity (11-18 times higher)
Micheli, F., Halpern, B. S., Botsford, L. W., & Warner, R. R. (2004)
Ecological Applications, 14(6), 1709-1723.
Marine reserves are effective in enhancing local abundances of exploited species and restoring the structure of whole communities, though these changes occur through a series of transient states and, for some communities, over long time frames (decades). In contrast with the more predictable increases of aggregate community variables such as total abundance and biomass, individual species and community structure exhibited broad variation in their responses to protection.
Gell, F.R. and Roberts, C.M. (2003)
Trends in Ecology & Evolution 18(9), 448-455 DOI: 10.1016/S0169-5347(03)00189-7
By integrating large-scale marine reserves into fisheries management plans, the decline in global fisheries and destruction of crucial habitats can be reversed.
Halpern, B.S. (2003)
Ecological applications, 13(sp1), 117-137.
Results from 89 studies found that nearly any marine ecosystem, regardless of their size, could benefit from a no-take reserve by increasing key biological measures such as density, biomass, size of marine species, and diversity.
Halpern, B. S. and Warner, R. R. (2003)
Proc Royal Society London Ser B Biol Sci 270:1871-1878
Given the high fecundity of most marine prganisms and recent evidence for limited distance of larval dispersal, it is likely that reserves can both maintain their own biodiversity adn service nearby non-reserve areas
Russ, G.R., Alcala, A.C., and Maypa, A.P. (2003)
Marine Ecology Progress Series, 264, 15-20
Biomass of surgeonfish tripled over 18 years within the reserve and catch per unit effort was 45 times higher, supporting the idea that no-take marine reserves can benefit fisheries through the ‘spillover effect.’
Areas: Apo Island, Philippines
Halpern, B. S. and Warner, R. R. (2002)
Ecology Letters, 5: 361–366. doi: 10.1046/j.1461-0248.2002.00326.x
The higher average values of density, biomass, average organism size, and diversity inside reserves (relative to controls) reach mean levels within a short (1–3 y) period of time and that the values are subsequently consistent across reserves of all ages (up to 40 y). Therefore, biological responses inside marine reserves appear to develop quickly and last through time.
Tawake, A., Gell, F. and Roberts, C.(2002)
WWF US, Washington D.C. pp 59-62
Extensive field research confirms many of these predictions. Reserves worldwide have led to increases in abundance, body size, biomass and reproductive output of exploited species
Manriquez, P. H. and Castilla, J. C. (2001)
Marine Ecology Progress Series 215: 201–211.
We concluded that protected areas may play an important role in the natural replinishment of C. concholepas stocks
Areas: Las Cruces, Chile
Roberts, C. M., Bohnsack, J. A., Gell, F., Hawkins, J. P., and Goodridge, R. (2001)
Science, 294(5548), 1920-1923 DOI: 10.1126/science.294.5548.1920
Marine reserves can enhance fisheries adjacent to the reserves by increasing catches of artisanal fishers by, thus marine reserves have the dual potential to support fisheries and conservation.
Tawake, A., Parks, J., Radikedike, P., Aalbersberg, B., Vuki, V. and Salafsky, N. (2001).
Conservation in Practice, 2: 32-35. doi: 10.1111/j. 1526-4629.2001.tb00020x
Not only can communities do good monitoring, but also, ultimately, involving the cimmunity in monitoring leads to conservation success in all sorts of unanticipated ways
McClanahan, T.R. and Mangi, S. (2000)
Ecological Applications 10:1792-1805 doi.org/10.1890/1051-0761(2000)010
The role of a marine protected area in enhancing local fisheries, through the emigration or spillover of exploitable fishes, was studied in a coral reef park (Mombasa Marine Park, Kenya) and fishery over a seven-year period during a time when the park's border changed and pull seines were eliminated. On the managed side, the park significantly increased the catch per fisher and catch per area by >50%, but even after the park's size was reduces , the total catch was reduced by ~30%
Areas: Mombasa Marine Park, Kenya
Mosquera, I., Côté, I. M., Jennings, S., & Reynolds, J. D. (2000)
Animal Conservation, 3(4), 321-332.
This meta-analysis found fish to be 3.7 time more abundant inside no-take marine reserves than outside reserve boundaries, mainly due to a positive response of species that had been targeted by fisheries.
Carter, J.C., Bustamante, R.H. (1997)
Proc Eighth Int Coral Reef Symp, Balboa 2:1911-1916
In sites where fishing has been halted over time, fishes are more numerous and on average larger relative to unprotected areas.
Stoner, A. W. and Ray, M. (1996)
Fish Bull (Wash D C) 94:551-565
A comparison of population structure of the commercially and culturally significant gastropod Strombus gigas, queen conch, was made between a fished area and an MFR in the Exuna Cays, an island chain in the central Bahamas
Areas: Exuna Cays, Bahamas
Alcala, A.C. (1988)
The data revealed that protection at the ten-year site was responsible for maintaining high fish yields; it was also shown that the reserve exported biomass to the non-reserve (fishing) area.