Monitoring coral bleaching using a colour reference card

• DOI: 10.1007/s00338-006-0123-8
• Publication Date: 2006-06-12T09:04:51Z
• Authors: U. E. Siebeck; N. J. Marshall; A. Klüter; Ove Hoegh-Guldberg
• Keywords: Ocean; 0106 biological sciences; Monitoring; Algae; Zooxanthellae; 01 natural sciences; 333; C1; Reef Condition; Irradiance; Marine & Freshwater Biology; 14. Life underwater; Mortality; Patterns; 770307 Marine protected areas; Future; Coral Colour; Coral Bleaching; Pigmentation; Coral Condition Assessment; Temperature; 13. Climate action; Reefs; Global Climate Change

Assessment of the extent of coral bleaching has become an important part of studies that aim to understand the condition of coral reefs. In this study a reference card that uses differences in coral colour was developed as an inexpensive, rapid and non-invasive method for the assessment of bleaching. The card uses a 6 point brightness/saturation scale within four colour hues to record changes in bleaching state. Changes on the scale of 2 units or more reflect a change in symbiont density and chlorophyll a content, and therefore the bleaching state of the coral. When used by non-specialist observers in the field (here on an intertidal reef flat), there was an inter-observer error of ± 1 colour score. This technique improves on existing subjective assessment of bleaching state by visual observation and offers the potential for rapid, wide-area assessment of changing coral condition.