A New Non-Invasive Technique for Temporarily Tagging Coral Reef Fishes

Abstract

The ability to identify individuals is important for the success of many behavioral and ecological studies. In fishes, there is a lot of variation in body size, shape, skin thickness, behavior, and ecology, which means that any given marking/ tagging method may not work well for all species. For the Humbug Damselfish Dascyllus aruanus, a widely used model species of coral-reef fish, we found that standard tagging methodologies (e.g., phenotypic variation, beads and PVC tags, fluorescent elastomer injections) were ineffective as they could not be applied to the fish or easily detected by observers or from videos. In response, we developed a new method to temporarily tag D. aruanus using colored plastic films and topical surgical glue. These films were easily detectable both directly by human observers and indirectly by video/photo-cameras. We tested the efficacy of this new method by examining the survival time of the tags at various positions on the body. Our results showed that the optimal tag locations were dorsal anterior (with a median attachment time of 53 hours) and dorsal middle (with a median attachment time of 49 hours). Total length of fish was not a significant predictor of tag life. In sum, we demonstrate an effective new method for temporarily tagging a widely studied coral reef fish. This method could be applied to other fishes and aquatic organisms (e.g., amphibians) in both marine and freshwater ecosystems.