| dc.description.abstract | This research investigates the effects of reefs on fish communities in the southern North Sea and indicates whether there could be spillover of fish species of commercial interest. Knowledge on these effects is important to provide background information for projects on oyster reef restoration and can be used in the design of offshore wind farms, which is a relevant topic with various of such projects being executed. To answer the research questions, video footage was analysed from cameras on baited remote underwater video systems placed on sampling stations inside and outside the Voordelta shellfish reef and the Borkum stones area. For each station the number of different species and the maximum number of individuals per species present on the footage was noted. The stations inside the reef were then compared to the stations outside of the reef. In the Voordelta, the species richness and the total abundance was greater inside the reef than outside of the reef. In the Borkum area the species richness and abundance were slightly higher outside of the reef compared to inside of the reef, but not significantly. However, the results of the PERMANOVA of both areas demonstrate that there is a clear distinction between the stations located inside of the reef and outside of the reef. This study concludes that shellfish reefs, like the one in the Voordelta, enhance species richness and abundance, and provide nursery or foraging areas for juvenile horse mackerel and seabass, which are commercial species. In a rocky reef like the Borkum stones area the difference between inside and outside of the reef is less pronounced, but the rocky reef still provides a higher diversity in the entire area and attracts species such as cod and whiting. | |
