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Sewage Pollution: Mitigation Is Key For Coral Reef Stewardship

In this new paper, the authors highlight the importance of addressing sewage, a global stressor affecting coral reefs. The authors note that of 112 coral reef geographies, 104 have documented sewage contamination problems, with the majority documenting direct ocean discharge. Despite this threat, the authors find that scientists and conservationists have paid less attention to understanding and abating sewage impacts on coral reefs, as compared to other stressors like overfishing. They suggest that reasons for this include the challenges of dealing with a large-scale diffuse threat, the diversity of pollutants involved, the high cost of water-treatment facilities, and bureaucracy. The authors explore how sewage discharge is often mischaracterized as a single stressor in coral reef management and suggest that it is important to recognize that sewage is a conglomerate of many potentially toxic and distinct stressors, including freshwater, inorganic nutrients, pathogens, endocrine disrupters, suspended solids, sediments, heavy metals, and other toxins. The authors state that mitigating the threat of sewage pollution will require: 1) understanding tolerance thresholds that corals have to sewage exposure, evaluating individual contaminants, additive, and synergistic combinations of contaminants; 2) quantifying the spatial extent and magnitude of the sewage discharge problems; and, most importantly, (3) testing both proactive and reactive strategies that can be employed to reduce the adverse impacts of human sewage in tropical coastal waters.

Author: Wear, S.L. and R. Vega-Thurber
Year: 2015
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Annuals of the New York Academy of Sciences: 1–16. doi: 10.1111/nyas.12785

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The Intrinsic Vulnerability To Fishing Of Coral Reef Fishes And Their Differential Recovery In Fishery Closures

Coral reef fisheries play a role in livelihoods and local economies around the world, but the impacts of fishing on targeted species of reef fish is poorly understood. The authors of this study examined the vulnerability of different species of coral reef fish to fisheries and evaluated the effectiveness of no-take reserves and periodically-harvested closures. Using life history traits to characterize the vulnerability of fish species to fishing, they found that larger-bodied carnivorous fish have a higher vulnerability compared to smaller-bodied herbivores and detritivores. In no-take areas, moderately to highly vulnerable species take a significantly longer time (decades) to recover than less vulnerable species. Based on these findings, they make the following recommendations for managers:

    • Expand studies of reef fish to improve estimates of vulnerability; Maintain long-term (20-40 year) no-take areas for full population recovery
    • Enforce compliance of no-take areas
    • Control timing and intensity of periodic closures for long-term fishery benefits
    • Use periodic and closures and no-take areas together as fishery management tools

    Author: Abesamis, R.A., A.L. Green, G.R. Russ, and C.R.L. Jadloc
    Year: 2014
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    Email for the full article: resilience@tnc.org

    Reviews in Fish Biology and Fisheries. doi: 10.1007/s11160-014-9362-x

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Recovery Potential Of The World’s Coral Reef Fishes

Fishing is the primary source of reduced reef function globally. Marine reserves are a critical tool to help fish populations recover, however, there are no benchmarks to determine if the protection is effective, or whether a reserve has recovered enough to be fished again. By studying remote and marine protected areas, they estimate how many fish would be on a coral reef without fishing, and how long it should take newly protected areas to recover. This helps to assess the impact of reef fisheries, and make informed management decisions that include timeframes for recovery.

Specifically, this paper presents the first empirical estimate of coral reef fisheries recovery potential, compiling data from 832 coral reefs across 64 localities (countries and territories. The authors estimate the expected density of reef fish on unfished reefs; quantify the rate of reef fish biomass recovery in well-enforced marine reserves; characterize the state of reef fish communities within fished and managed areas; predict the time required to recover biomass and ecosystem functions; and explore the potential returns in biomass and function using off-reserve management throughout the broader reefscape. The research team studied the fish biomass on coral reefs around the world and discovered that near-pristine reefs contain 1,000 kg of fish per hectare. Using this figure as a benchmark, they found that 83% of fished reefs have lost more than half of their fish biomass (volume of fish).

The authors discuss how reef fish populations were better off when fishing activities were restricted (e.g., including limitations on the species that could be caught, the gears that could be used, and controlled access rights). The authors determined that once protected, fished reefs take about 35 years to recover, while heavily depleted reefs take almost 60 years. Although the influence of marine reserves can be detected within several years, this global analysis demonstrated that full recovery of reef fish biomass takes decades to achieve. Importantly, this suggests that most marine reserves implemented in the past 10–20 years, will require many more years to achieve their recovery potential. This has important implications for managing expectations of MPAs and also reinforces the need for continued, effective protection and consideration of other viable management options. The authors also found that in reef areas where MPAs cannot be implemented, a range of fisheries can have substantial effects on fish functional groups that support important reef processes.

Author: MacNeil, M.A., N.A.J. Graham, J.E. Cinner, S.K. Wilson, I.D. Williams, J. Maina, S. Newman, A.M. Friedlander, S. Jupiter, N.V.C. Polunin, and T.R. McClanahan
Year: 2015
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Email for the full article: resilience@tnc.org

Nature 520: 341-344. doi:10.1038/nature14358

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Using Wastewater Treatment Technologies to Reduce Nutrient Pollution Impacts on Coral Reefs

Watch on YouTube

March 11, 2015

Jim Bays, Technology Fellow at CH2M HILL discusses wastewater treatment technologies ranging from low-tech onsite treatment to large system level upgrades that improve public health and mitigate nutrient pollution impact to coral reefs and sensitive marine ecosystems. Case histories from small communities, resorts and large cities in coral reef areas are shared. Click here for resources from the presentation.

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Persistence and Change in Community Composition of Reef Corals through Present, Past and Future Climates

This study looked at long-term data from fossil and modern coral reefs to test for variation among coral genera over time, both in rates and directions of change in abundance. Data was synthesized from seven extant reefs, creating 78 trajectories of changing coral cover by genus in the Caribbean and 153 trajectories in the Indo-Pacific. Fossil records from 70 localities from late Miocene to late Pleistocene were used to understand the temporal nature of changes affecting current coral reef communities. A model was developed to evaluate potential coral reef composition of the future under increased thermal stress predicted by climate change. The model suggested that coral mortality and adult coral growth were the most important ecological indicators of coral persistence; thermal tolerance became increasingly important when looking at severe climate change. Overall, corals most likely to persist in future climate scenarios are characterized by rapid growth and moderate mortality but changes in the genera of coral composition in the future are likely to occur.

Author: Edmunds, P.J., M. Adjeroud, M.L. Baskett, I.B. Baums, A.F. Budd, et al.
Year: 2014
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PLoS ONE 9(10): e107525. doi: 10.1371/journal.pone.0107525

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New and improved Network Forum

The Reef Resilience Network has launched a new and improved online discussion forum!

Now part of the Reef Resilience website, this interactive online community is a place where coral reef managers and practitioners from around the world can connect and share with others to better manage marine resources.

If you work to protect, manage, or promote coral reefs please join the conversation: www.reefresilience.org/network

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New Reef Resilience Online Course Launched

The new online course Advanced Studies in Coral Reef Resilience is designed to provide coral reef managers and practitioners in-depth guidance on managing for resilience. This free course incorporates new science, case studies, and management practices described in the Reef Resilience Toolkit.

The course includes six modules that discuss local and global stressors affecting coral reefs, guidance for identifying coral reef resilience indicators, design principles for resilient MPA networks, methods for implementing resilience assessments, and important communication tools for managers. Course participants can choose to complete any or all lessons within course modules. Read more.

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Meta-Analysis Indicates Habitat-Specific Alterations to Primary Producer and Herbivore Communities in Marine Protected Areas

A recent global quantitative review and meta-analysis was conducted on the effects of MPAs on coral reef herbivores and primary producers to support management decisions. Based on criteria for the meta-analysis, which included only well-enforced no-take MPAs, 41 individual publications representing 57 MPAs worldwide were included in the study. The authors found that within MPAs, macroalgal cover and sea urchin density were significantly lower as compared to fished areas. The relationship between macroalgae cover and herbivores was also explored. MPAs with higher populations of herbivorous fishes had significantly lower macroalgal cover. The authors conclude that the community response to MPAs is highly variable. Management implications include protecting key echinoid predators which appear crucial to the recovery of reefs. Also, actively managing grazers and predators should be an integral component of MPA design.

Author: Gilby, B.L. and T. Stevens
Year: 2014
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Global Ecology and Conservation 2: 289-299. doi: 0.1016/j.gecco.2014.10.005

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Developing Marine Protected Area Networks in the Coral Triangle: Good Practices for Expanding the Coral Triangle Marine Protected Area System

The authors describe six case studies of marine protected area (MPA) networks in the Coral Triangle region that differ in scale and the approach taken to establish the networks. These are:

  • Nusa Penida in Indonesia
  • Tun Mustapha Park in Malaysia
  • Kimbe Bay in Papua New Guinea
  • Verde Island Passage in the Philippines
  • The Lauru Ridges to Reefs Protected Area Network in Choiseul, Solomon Islands
  • Nino Konis Santana Park in Timor Leste

Through a synthesis of these case studies, common themes underlying successful outcomes were generated. These are:

  • Multi-stakeholder and cross-level management institutions: because ecological and institutional boundaries rarely overlap, multi-scale management and governance are needed for effective management
  • Integrated scientific information and local knowledge and traditions: MPA networks designed using scientific information and local knowledge that include stakeholder involvement typically have better compliance and community ownership
  • Building capacity for local responsibility and leadership: while all MPAs in the case studies above had the involvement of nongovernmental organizations (NGOs), technical support should build the capacity for local management and leadership for long-term success
  • Multiple-use zoning to balance objectives: this flexible approach allows multiple objectives of the MPA network to be met for a broad range of stakeholder interests
  • Learning networks: Dissemination of lessons learned and best practices for MPA networks, and support networks are needed to share experiences and facilitate effective management

Author: Weeks, R., P.M. Aliño, S. Atkinson, P. Beldia II, A. Binson, W.L. Campos, R. Djohani, A.L. Green, R. Hamilton, V. Horigue, R. Jumin, K. Kalim, A. Kasasiah, J. Kereseka, C. Klein, L. Laroya, S. Magupin, B. Masike, C. Mohan, R.M. Da Silva Pinto, A. Vave-Karamui, C. Villanoy, M. Welly, and A.T. White
Year: 2014
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Email for the full article: resilience@tnc.org

Coastal Management 42(2): 183-205. doi: 10.1080/08920753.2014.877768

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