Fluorescence census techniques for the early detection of coral recruits
Many coral recruits are very small and often cryptic at settlement making them difficult to detect with normal census techniques. Here we show that fluorescence census techniques can increase the accuracy of juvenile coral counts in highly fluorescent taxa. Using fluorescent filters at night, counts of coral recruits were 20–50% higher than during the day. Acropora abundances were up to 300% higher, the difference being made up of cryptic individuals, and individuals that were too small to see during the day. Fluorescence techniques will be particularly useful in regions where fluorescent taxa are dominant, such as most Indo-Pacific reefs. The technique offers particular promise to determine the influence of early post-settlement mortality on the ecology of fluorescent taxa, because corals can be detected at the size at which they settle.
KeywordsCoral reefs Acropora Fluorescence Recruitment Settlement Mortality
This work was supported by ARC Fellowships to A. Baird and A. Salih and Undersea Explorer (UE). We thank UE crew and sponsors (Carl Zeiss Pty Ltd. & Varian) of the Coral Light and Life Workshop, and C. Mazel for comments on the manuscript.
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