Identification of coral disease within the high-latitude reef, Lord Howe Island Marine Park

Coral disease prevalence has significantly increased under a changing climate, impacting coral community structure and functionality. The impacts and ecology of coral diseases are unclear in most high-latitude reefs (coral reefs above 28 degrees north and below 28 degrees south). High-latitude locations are vulnerable to climate change; therefore, identifying diseases and developing region-specific baselines are important for local management. We report the first coral disease findings at the UNESCO World Heritage listed Lord Howe Island Marine Park (31.5 degrees S, 159 degrees E), the southernmost coral reef system. This study assessed coral disease prevalence during November 2018, March 2019 and October 2019. Surveys from three lagoonal reefs identified four coral diseases: white syndrome, skeletal eroding band, growth anomalies and endolithic hypermycosis impacting six coral taxa (Acropora, Isopora, Montipora, Pocillopora, Porites and Seriatopora). Overall, disease prevalence was 5 +/- 1% and significantly differed between time and site. Disease prevalence was highest in November 2018 (10 +/- 1%) and significantly lower during March 2019 (5 +/- 1%), coinciding with a bleaching event. White syndrome was the most prevalent disease (4 +/- 1%) with 83 colonies of six taxa affected, predominately Isopora. Acroporids recorded the highest disease susceptibility, with three of the four diseases observed. Documenting baseline coral disease prevalence and monitoring throughout a bleaching event assists our understanding of disease ecology dynamics under current climate change impacts at high-latitude reefs.

Automated summary

The prevalence of coral disease has increased significantly under climate change, affecting coral community structure and functionality. The impacts and ecology of coral diseases in high-latitude reefs remain unclear. This study reports the first findings of coral diseases in Lord Howe Island Marine Park, the southernmost coral reef system. Four coral diseases were identified, with a prevalence of 5% and significant variations between time and site.