The effect of a large artificial reef on fish abundance was tested using drop cameras. This novel method involves deploying drop cameras quickly, many times, at a range of distances from the reef, and the observed fish abundance is analysed using regression. Distance from the artificial reef was a significant predictor of fish abundance and species diversity. Fish abundance declined exponentially with distance, halving approximately every 20 m from the reef. Eight species could be tested individually; four of these associated positively with the artificial reef, two were predicted better by microhabitat, and two benthic species showed no association with the reef. Two pelagic species, kingfish and yellow-tail scad, were among the species associated with the reef, which shows that offshore artificial reefs can be successful as recreational fishing targets.

This approach to quantifying spatial relationships shows promise as a tool for aquatic environments. Drop cameras can be time-expensive and provide sparse coverage compared to traditional sonar methods, but can identify species accurately, yield detailed bottom-type information, and observe reef and benthic species (which are difficult or impossible to resolve with sonar). Using regression to examine spatially-explicit associations and distributions is a recent development in terrestrial vegetation modelling. Its use here shows it can be a powerful tool for understanding aquatic environments as well.