Project completed by Izzy Nikazy

Research Questions / Objectives

This project aimed to establish accurate baseline data on coral disease prevalence, incidence, and mortality across two heavily impacted reef systems on O’ahu’s southern shore: Maunalua Bay and Kewalo Basin. The primary research questions included:

1. What is the current prevalence of key coral diseases (White Syndrome, Tissue Loss Diseases, Growth Anomalies, Pigmentation Responses)?
2. How do prevalence and incidence vary between sites subject to differing anthropogenic pressures (urban runoff, coastal development, restoration activity)?
3. What role can photogrammetry and time-series monitoring play in improving accuracy and tracking lesion progression?
4. Inform the scientific community on the current/evolving state of O’ahu’s reefs.

Methods

Weekly surveys were conducted along 30 × 2 m belt transects at both sites.

• Buddy Team 1 recorded coral colony counts by genus, focusing on Porites, Montipora, Pocillopora, Pavona, Leptastrea, and Fungia.
• Buddy Team 2 documented visible signs of disease (White Syndrome, Tissue Loss, Growth Anomalies, Pigmentation Responses).
• Photogrammetry was performed on the same transects and on four permanent 5 × 5 m plots (DHSE, SHSW, TC1, TC2). Using structure-from-motion software, orthomosaics were generated and analyzed in TagLab for live tissue area and lesion progression. This approach provided more precise and replicable counts, reducing human error and bias. 

Results

Preliminary surveys revealed site-specific variation in disease prevalence.

• Pocillopora Tissue Loss Disease was highest at Kewalo Basin SHSW (31.4%), indicating strong site-specific disease presence.
• Montipora White Syndrome and Growth Anomalies were most prevalent at Maunalua Bay TC1-S, with 11.8% and 19.7%, respectively.
• Several sites, including TC4-S and SHSE, showed 0% disease, suggesting localized reef resilience.

Significance
By comparing prevalence, incidence, and mortality across sites, this project highlights the ecological consequences of coastal development and urban runoff. Coral disease addresses a critical gap in reef monitoring and management literature on O’ahu, making these baseline datasets a critical step in filling that void. These findings are directly relevant to local restoration initiatives and inform state management priorities by providing quantitative baselines against which future disease progression can be measured. This work also represents a publishable collaboration with DAR, providing urgently needed insight into O’ahu’s coral health.