Coral disease prevalence estimation and sampling design

Area of Science:

• Marine Biology
• Ecology
• Conservation Science

Background:

• Coral reef ecosystems face significant threats from diseases, altering their structure and function globally.
• Existing studies on coral diseases often adapt sampling designs not optimized for disease ecology.

Purpose of the Study:

• To evaluate the efficiency of common coral disease sampling protocols.
• To assess the impact of coral colony distribution and disease transmission patterns on sampling accuracy.
• To determine the statistical confidence in disease prevalence estimates derived from current methods.

Main Methods:

• Generated virtual coral population data for *Orbicella faveolata* in the Mexican Caribbean.
• Simulated six scenarios with varying coral distribution patterns (random, clustered, over-dispersed) and disease transmission (random, contagious).
• Employed standard belt-transect sampling with diverse sample-unit sizes (10x1m to 50x2m).

Main Results:

• Low probability (11-48%) of achieving a mean coral disease prevalence estimate within ±5% of the true value.
• Low statistical power for two-sample comparisons, requiring very large effect sizes.
• Identified insufficient sample size, neglecting local coral density and spatial distribution, as a key limitation.

Conclusions:

• Commonly used coral disease sampling protocols exhibit low efficiency and statistical power.
• Current methods provide low confidence for assessing changes in coral disease prevalence.
• Sampling protocols require adjustment to incorporate local coral species' characteristics for accurate disease monitoring.