Wind farms and their influence on the occurrence of ichthyoplankton and squid larvae

Changes in the seafloor structure induced by the introduction of wind farms are expected to influence fish populations depositing their eggs on the seafloor, since they are known to require a specific substrate for spawning. Hard substrate creation can also influence egg deposition opportunities for invertebrates, such as the commercially important cuttlefish and different species of squids. So, wind farm construction is expected to have positive effects on fish and invertebrate species that require hard substrates for spawning, and this is expected to manifest as higher densities of early life stages at the hard substrates (eggs) and in the water column (larvae) at the wind farms. This was investigated at the Thorntonbank wind farm by repeatedly sampling three impact stations and three reference stations with a Bongo net from 2010 to 2013. The results do not show significant effects of the wind farm on fish eggs, fish larvae and squid larvae. Nevertheless, the data provide good baseline information about ichthyoplankton and squid larvae at offshore stations that can be used in future monitoring. When planning future monitoring activities at this site, adaptations to the design should be incorporated and alternative methods for quantifying squid larvae should be considered