Optimization of video monitoring of fish for reef assessment and management

Underwater video recordings provide a panoramic window into aquatic ecosystems. Camera technologies are rapidly advancing and become increasingly popular in ecological studies. However, to allow optimal use of these techniques, scientifically underbuilt methodologies are key. To this end, during a sampling campaign in 2017, reef fish were monitored via different setups of GoPro cameras at 10 sites in Santa Cruz and Floreana islands of the Galapagos Archipelago. The objective of this study was to determine the effect of scale, tides, camera setups, duration, repetitions as well as (number of) persons involved in snorkeling. Based on numerical analysis, an optimal approach was developed in order to maximize the reliability, repeatability and efficiency of fish monitoring.