Comparison of video and traps for detecting reef fishes and quantifying species richness in the continental shelf waters of the southeast USA

Abstract

The management of reef-associated fish species is challenging due to their life history characteristics and occurrence in rocky reef habitats that are difficult to sample using traditional sampling gears. We compared 2 common sampling gears for reef fish species, chevron traps and underwater video, using 5 yr of comprehensive paired sampling data (N = 7034) collected at reef habitats between North Carolina and Florida along the southeast United States Atlantic continental shelf. Most fish families (80%) and species (85%) were observed significantly more often on video than caught in traps, and only 2 species out of 40 (5%)—black sea bass Centropristis striata and bank sea bass C.ocyurus—were caught significantly more often in traps than observed on video. Moreover, site-specific species richness was approximately 3-4 times higher on average for video compared to traps. We also used a generalized additive model to show that the ratio of trap-caught species to video-observed species was higher in shallower waters off North and South Carolina, especially when water clarity was low. Results demonstrate that video can be an efficient gear to sample most reef fishes around the world but may provide even greater benefits when paired with traditional sampling gears like traps to leverage the strengths of each gear for estimating relative abundance and species richness with more certainty.