Comparison of Cuban coral and reef fish assemblages recorded by visual census and underwater stereo-video technique

Abstract

Visual census techniques have been used worldwide for the documentation of indicators on coral reefs condition, and its outcomes have helped to validate other techniques such as the use of video recording. Among them, those that use video are recommended to increase reef coverage in less time. This work aimed at verifying whether indicators of coral reefs condition documented with visual census (VC) and stereo-video operated by a diver (SV) offer comparable results when monitoring methodologies implemented in Cuba are followed. The estimates of diversity and structure of the corals and reef fish associations (species composition, abundance and size) obtained from the simultaneous data collection with VC and SV were compared. Samples were carried out with linear transects: 10 m for coral associations, 50 × 2 m for fish associations, and 800 × 10 m for commercially important fish species. The estimates of coral and fish associations obtained were similar with both techniques. The lower number of species identified and the higher proportion of individuals classified at the genus level obtained with SV were the main source of variation between the techniques, mainly for fish. The work corroborated the efficacy of SV in obtaining accurate measurements of Caribbean reef fish associations and demonstrated for the first time, that SV can be used to characterize coral associations. According to these results, spatial or temporal comparisons may be valid regardless of the sampling technique used. This has application in Cuba, where VC have predominated in the characterization of reefs and where it is necessary to increase the surface of monitored reefs. Therefore, the introduction of SV is recommended as a complement to VC or as an alternative when VC cannot be implemented.

Keywords

• Indicators of condition
• Sample techniques
• Coral reef
• Caribbean