Most biological data for coral reef monitoring are collected by human observers. This could be resource-intensive for long-term studies and thus hard to maintain consistency on large spatial scale. While remote sensing can be applied on a macro scale, are there any automated observational platforms that are available to look at events on a smaller scale such as behavior of fish colonies around reefs?
There are several researchers I know, including myself and others in my former grad school lab that are collecting acoustic data, or video data, for monitoring coral reefs using deployed underwater microphones and/or cameras that run for days to months at a time.
There are some papers exploring how reef sounds can be measured to monitor health, e.g., some have found healthier reefs to be 'louder' and have more fish calls, and sometimes these correlate positively with metrics usually obtained from visual surveys, such as coral cover and fish abundance.
For some examples of different sensing platforms, I recommend looking at the following papers and others by these authors. Some are in habitats other than coral reefs, but utilize methods that could be applied to coral reefs:
Some camera or acoustic systems were custom built for these studies. Others, like SoundTraps, are commercially available.