Evaluating the effectiveness of baited video and traps for quantifying the mobile fauna on artificial reefs in northern China

Abstract

Baited remote underwater video (BRUV), with its non-destructive nature and ease of replication, is an effective and widely used method to record the relative abundance and behavior of aquatic fauna. However, the effectiveness of BRUVs for investigating the structural and functional diversity of mobile fauna on artificial reefs has not been fully evaluated. In China artificial reefs form an important component of very extensive marine ranching systems along the coast. This study used BRUVs and baited fish traps (traps), a traditional and popular fishing gear in the coastal waters of northern China, over six months to quantify the mobile fauna around artificial reefs and adjacent natural substrate (“control”) and compared the richness, abundance, community composition and functional diversity of reefs and control areas and BRUVs and traps. A significantly greater number of species and relative abundance was recorded using BRUVs than traps. Significant differences in faunal composition were detected between the two methods (BRUVs, traps), the two habitats (artificial reef, control) and the seven sampling occasions. Measures of functional diversity were also all significantly higher using data derived from BRUVs than traps. The weighted average analysis of functional traits revealed that those related to feeding and space use were more diverse from BRUVs. These results indicate that BRUVs provided a more complete representation of the mobile fauna than traps and show great potential for fishery-independent monitoring of marine ranching in China.