Evaluating Small-Scale Marine Protected Areas
CCC support a new study that studies the effects of small-scale Marine Protected Areas on the coral reef fish communities in the Philippines
The study, “The Effect of Small-Scale Marine Protected Areas on the Coral Reef Fish Community Assemblage in the Philippines”, produced by Chris Gamlin MSc and supported by CCC, tackles issues caused by the global over-exploitation of coral reef fisheries.
The paper discusses the temporal changes and spatial differences in the coral reef associated fish community at the Napantao reef in Philippines over a six-year time period. By looking at both community and species-specific analysis, Chris was able to demonstrate that the use of a Marine Protected Area (MPA) leads to an increase in reef fish abundance and is an efficient protection technique against the impacts of overfishing.
The study was developed by Chris for his MSci in Marine Biology at the University of Southampton, of which he obtained a distinction.
Overexploitation of fisheries can lead to a decrease in catch per unit effort (CPUE) which results in a drop in overall fishery productivity. This often leads to the use of other destructive fishing techniques (such as utilising dynamite, cyanide, drop rocks, etc.) in an attempt to increase catch. Such practices lead to the destruction of the complex 3-dimensional reef structure that many coral reef associated fish depend upon for habitat, reproduction and feeding. The growing stressors that are affecting the coral reef communities are pushing the world’s reefs towards a point of no return, which consequently is calling for new strategies and approaches when it comes to preserving the functionality of the coral reefs.
The implementation of marine protected areas is increasingly considered in coastal areas to preserve fragile fauna and habitat from the effects of fishing and is one of the most commonly used management techniques in the protection of coral reefs. For the ecological benefit of the protected area, the enactment of the MPAs can range from a complete restriction of activity (e.g. no-take zones), to areas that have limited fishing activities and/or restrictions on specific fishing gear. However, due to the MPA effects being diverse in magnitude and range, their effectiveness is dependent on factors such as species and time with respect to the MPAs establishment.
To address this, the paper assesses and analyses coral reef fish abundance, commercially important fish size class frequency and benthic substratum data over a six year period from 2013 to 2018. Data was collected across 2,000m3 as the surveys were conducted biannually along 6 permanent transect sites that were positioned at a depth of around 12m where topography allowed.
Over the six-year period from 2013-2018, a total of 32,669 fish were recorded from 26 Families and one Superorder. The analysis indicated a 48.6% increase in average abundance of coral reef associated fishes inside the Napantao MPA from 2013 to 2018 whereas outside the MPA saw a 26.2% increase over the allocated study period. The increase in abundance outside the MPA, which was likely due to a spill-over effect, indicate that the MPA is to some extent successfully increasing local fishery production. There was also an overall increase in species richness both inside and outside the MPA across the 6 year time-frame; 1.9% and 10.6% respectively.
The analysis suggests that the coral reef fish community composition was more variable outside the MPA over the duration of the study period, with the fusiliers (Caesionidae) and the cardinalfish (Apogonidae) actively contributing the most to the dissimilarity. This variability in coral reef fish community composition outside the MPA indicates a more stable population inside the MPA, which has been attributed to this area being considered healthier and more resilient to stress. Interestingly, the hard coral cover inside the MPA boundary had decreased by 4% from 2013-2018 whereas in contrast, outside the MPA, hard coral cover has increased by 10.1%.
Overall, the reef fish abundances inside the MPA appear to be increasing in recent years. However, the effects of overfishing that is continued outside the boundaries of the MPA outweigh the spill-over of the reef associated fish, and the MPA has yet to meet its target of increased fishery production. Enforcing stricter laws (e.g. species-specific size catch restrictions) may increase the proportions of exploited fish that reach a stage of sexual maturity which could ultimately lead to long-term sustainability of the fishery.
In summary, the paper demonstrates that the area protected by the MPA in Napantao is host to a more diverse and temporally more viable community, indicating a healthier and more complex reef which is more resilient to local stressors than the surrounding unprotected areas. Therefore, the implementation of MPA systems in tropical marine habitats is achievable, even on a small-scale, and can contribute largely to the preservation of the coral reef fish community assemblage.
If you would like more information about the study, you can contact Chris at c.gamlin@hotmail.co.uk or alternatively, our Head of Science at headofscience@coralcay.org
