Influence of Offshore Wind Farm on Shore Crab Carcinus maenas Population Dynamics

Abstract

Many governments have initiated programs of energy production from renewable sources in response to climate changes induced by gases from burning fossil fuels. Use of wind energy is considered a sustainable way of reducing the carbon emission, and offshore wind power generation capacity is expected to grow significantly as the world is trying to make a transition to a lower carbon economy. Though the advantages of renewable energy on a global scale are not in doubt, the effects on the local environment must also be carefully considered. The aim of this study was to investigate the influence of offshore windfarm on shore crab (Carcinus maenas) population dynamics. Data were collected in the Öresund strait in Southern Sweden at Lillgrund offshore windfarm and in to adjacent control areas, Sjollen and Bredgrund. The mark-recapture method was applied to make population size estimation, and the catch per unit effort index was calculated as a measure of abundance. Data on catch per unit effort were also calculated for 8 previous years with data collected from earlier studies in the areas. In addition, size, sex ratio, condition and color were recorded. Due to few recaptures, reliable population size estimations could not be achieved. The population of shore crab within the windfarm was found to be significantly more abundant than those in the control areas in 2012. However, analysis of catch per unit effort in a long term perspective of 10 years, show no effect of the offshore windfarm on shore crab abundance. There was not found any effect of the presence of wind farm on shore crabs regarding size, sex ratio, condition or color.