Abstract

Nassau groupers, Epinephelus striatus, have patterns of dark spots around their eyes. This study investigated whether these spots could be used as natural markers to identify individuals from digital photographs taken in situ. In order to serve as useful natural tags, markings need to be unique, to persist over time and to be distinguishable from photographs without the need to capture individuals. Photographs were taken of juvenile Nassau groupers ranging in size from an estimated 9 to 40 cm TL in a seagrass area in South Caicos, Turks and Caicos Islands. Individuals appeared to display unique patterns of spots. Individuals were recognisable by the spots around their eyes which persisted over the study period. These natural markers were recognizable from photographs taken with an unsophisticated underwater digital camera whilst SCUBA diving and snorkelling. The use of natural markings of Nassau groupers has the potential to enhance information collected during underwater visual census of this species.

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