Baited camera to identify macro-fauna species and their abundance in close proximity to seaweed farms : technical report

The ambitions for large scale cultivation of seaweed has been gaining in popularity, good ecological monitoring of these newly introduced habitats is necessary to assess the impact of these new habitats. Naturally occurring seaweed habitats provide a nursery for juvenile fish and have a high biodiversity. It is therefore expected that seaweed cultivation site will increase the local biodiversity. To be able to monitor this baited camera systems were selected as a potential solution for mobile species. Monitoring with a camera is the least intrusive method of monitoring and provided the additional advantage of video footage or pictures, which can be used in presentation of public outreach campaigns. In this study an infra-red camera was tested and compared with an action camera, using a baited camera setup. The setup proved to attract both omnivorous as carnivorous fish. However the time of day in which the monitoring was conducted proved important, in early afternoon recordings there is more activity recorded than in the early evening. Also a difference in season was found, as expected November showed different types of fish than July. Additionally the ability to taxonomically identify the fish was studied by comparing the footage of the infra-red camera with footage of the action cams. The footage of the infra-red camera was more difficult to identify fish on than the action camera’s. Additionally having multiple camera’s aimed at the bait from different angles provides better identification options. Identification proved to result in more difficulties, due to the nursery function of seaweed habitat most fish found where in their juvenile stage. It is expected that having a seaweed cultivation system will attract more biodiversity over time, a long scale monitoring over different seasons is therefore advised. To provide a wider range of identification options, automated visual recognition should be considered for future development.