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Sediment And Turbidity Associated With Offshore Dredging Increase Coral Disease Prevalence on Nearby Reefs

This study provides the first empirical evidence linking turbidity and sedimentation with elevated levels of coral disease and other indicators of compromised health in situ. The study was conducted in Australia’s Montebello and Barrow Islands, encompassing marine managed areas characterized by low human use, minimal development/industry and strict management. Detailed coral health assessments were conducted following the completion of an 18-month dredging project in 11 sites of varying sedimentation exposure. Every hard coral colony of 5 cm or greater in diameter along transects was surveyed to determine and classify disease presence, as well as other signs of compromised coral health. It was shown that coral reef exposure to the sediment plume was the main driver of higher levels of diseases and other indicators of degraded coral health. White syndromes (WS) disease prevalence strongly corresponded to high sedimentation and turbidity levels indicating the importance of water quality on coral disease and the need to manage coastal development to maintain nearshore reef health.

Author: Pollock, F.J., J.B. Lamb, S.N. Field, S.F. Heron, B. Schaffelke, et al.
Year: 2014
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PLoS ONE 9(7): e102498. doi: 10.1371/journal.pone.0102498

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Relationship Between Phylogeny And Immunity Suggests Older Caribbean Coral Lineages Are More Resistant to Disease

This study looked at the evolutionary importance of coral immune traits, which are related to phylogeny in other organisms. 140 different fragments from healthy coral colonies were sampled, representing 14 of the most common Caribbean hard corals (20% of regional hard coral diversity) to test for the presence of a phylogenetic signal in immune traits. Published disease data was compiled to determine levels of immune-competence by a number of diseases affecting each species and its mean prevalence in the population. Results showed that disease resistance varies significantly among coral taxa for some immune-related process; species with older lineages demonstrated less disease prevalence compared to modern lineages of corals. Older coral lineages (including Porites, Siderastrea radians and Meandrinidae) may be more resilient to conditions of the present and future.

Author: Pinzon, C J.H., J. Beach-Letendre, E. Weil, and L.D. Mydlarz
Year: 2014
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PLoS ONE 9(8): e104787. doi: 10.1371/journal.pone.0104787

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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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Status and Trends of Caribbean Coral Reefs: 1970-2012, Executive Summary

Since the early 1980s Caribbean coral reefs have suffered massive losses of corals. Impacts from human population growth, overfishing, coastal pollution, global warming and invasive species have resulted in decrease of coral populations, increases of seaweeds, outbreaks of coral bleaching and disease, and failure of corals to recover from natural disturbances. This study analyses the status and trends of reef communities throughout the wider Caribbean. Metadata on the nature of the reef environment, depth and history of human population growth, fishing, hurricanes, coral bleaching and disease was compiled and analyzed. In some cases, biological information for coral and macroalgal cover, abundance of grazing sea urchin Diadema antillarum, and biomass of fishes such as grazing parrotfish was also obtained. Results imply that the three best predictors of the decline in Caribbean coral cover over the past 30 or more years are: (a) outbreaks of Acropora and Diadema diseases (1970s and early 1980s); (b) overpopulation, including increase in tourism; and (c) overfishing of herbivores, particularly parrotfish. Coastal pollution is also significant and increasingly warming seas is also a threat but so far, extreme heating events have had only localized effects.

In summary, the degradation of Caribbean reefs has occurred in three distinct phases: (1) Massive losses of Acropora (mid-1970s to early 1980s) due to White Band Disease; (2) Increase in macroalgal cover and decrease in coral cover following the mass mortality of Diadema (1983) and (3) Continuation of the patterns established in Phase 2 worsened by more overfishing, coastal pollution, tourism, and extreme warming events. Four major recommendations for management emerge from this report:

  1. Adopt conservation and fisheries management strategies to restore parrotfish populations;
  2. Simplify and standardize monitoring of Caribbean reefs and make the results available on an annual basis;
  3. Foster communication and exchange of information;
  4. Develop and implement adaptive legislation and regulations to ensure that threats to coral reefs are systematically addressed.

Author: Jackson, J.B.C.
Year: 2014
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Global Coral Reef Monitoring Network, IUCN, Gland, Switzerland.

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Chronic Nutrient Enrichment Increases Prevalence and Severity of Coral Disease and Bleaching

After exposing test plots in the Florida Keys, USA to increased nutrients (at levels equivalent to nutrient input from onshore sources), researchers found that increased nutrient levels led to increased prevalence and severity of coral diseases and coral bleaching. However, one year after nutrient enrichment stopped, there were no differences in bleaching or disease, indicating that coastal nutrients are increasing prevalence of bleaching and disease. Local scale nutrient input may worsen the effects of global stressors, so limiting nutrient input may be an important management tool for reducing threats to corals. This study is the first to show that nutrients can cause an increase of prevalence of disease or bleaching in the field. 

Author:
Vega Thurber, R.L., D.E. Burkepile, C. Fuchs, A.A. Shantz, R. McMinds, and J.R. Zaneveld
Year: 2013
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Email for the full article: resilience@tnc.org

Global Change Biology 20(2): 544–554. doi:10.1111/gcb.12450

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A Framework for Responding to Coral Disease Outbreaks that Facilitates Adaptive Management

In this study, investigators develop and present a framework for responding to coral disease outbreaks with implications for reef ecosystem health. The framework contains four components, including an early warning system, a tiered impact assessment program, scaled management actions, and a communication plan.

A combination of predictive tools with in situ observations of areas at risk for disease outbreak constitute the early warning system, while reports of increasing disease prevalence triggers a tiered response of assessment, research, or management actions. Response to the disease outbreak risk is scaled based on the severity and spatial extent of impacts incurred by a disease outbreak to coral species.

Additionally, the study reviews potential management actions to mitigate coral disease impacts and facilitate recovery of the reef ecosystem, and considers coral disease-specific strategies as well as strategies already used in reef resilience.

Author: Beeden R., J.A. Maynard, P.A. Marshall, S.F. Heron, and B.L. Willis
Year: 2012
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Environmental Management 49:1–13. doi:10.1007/s00267-011-9770-9

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