Evaluation of an underwater solid state memory video system with application to fish abundance and diversity studies in southeast Australia

This paper describes a solid state memory (SSM) video camera system designed for extended deployment as a remote underwater video device with applications for measuring fish abundance and diversity. The video camera was evaluated in a series of lab-based trials to establish performance parameters (power consumption, data accumulation rates and maximum continuous recording time). The system performed reliably with a mean maximum continuous recording time of 13.3 (±0.3) h. Field trials were carried out to (a) compare results of video parameters, number of species identified (Nsp), maximum number of each species (MaxN) and time at first appearance of each species (TFAP) to a conventional standard definition video system and (b) examine the effect that a reduction in image resolution has on these parameters. Results indicated no significant differences between the standard definition camera and the test system at the highest resolution stetting (640 × 480). However, the total number of species identified by the reader was significantly less at the low resolution setting (176 × 144) and a significant reduction in relative abundance (MaxN) and TFAP were identified for both the mid (320 × 240) and lowest resolution (176 × 144) settings. Results indicate the solid state camera system is useful for extending recording time above that of standard definition cameras. However, there is limited potential to extend deployment times of BRUV systems via a reduction in video resolution without significant compromises to the accuracy and precision of the key indicators for diversity and abundance of fishes.

► We test a remote solid state memory (SSM) video system designed for extended deployments in the marine environment.
► Reduction in resolution resulted in significant differences in estimates of relative abundance and the number of species observed.
► Results indicate limited potential to extend deployment times of remote video observations through a reduction in video resolution.