Onderwatergeluid als stressor voor mariene vissen
Offshore wind energy contributes to achieve that 13% of Belgian primary energy use is produced by renewable energy sources by 2020. Intense impulse sound is generated during pile-driving of monopiles and less intense, continuous sound is generated during the operational phase. Underwater noise can disturb the natural behaviour and cause physical injuries in sea mammals and fish. Recent research hypothesizes reduced growth rates and viability for fish eggs and larvae, or even direct mortality in the vicinity of the construction zones.
The 11th descriptor to maintain a good environmental status (GES), defined by the Marine Strategy Framework Directive (MSFD), states that underwater noise is at levels that do not adversely affect the marine environment. The opportunity to research the effects of underwater noise on the different life stages of marine, commercially important fish species (European seabass Dicentrarchus labrax, sole Solea solea, cod Gadus morhua), presents itself during the construction and operation of the offshore wind farms at the Belgian coast.
The research focuses on the acute and chronic effects that both noise phases exercise on fish eggs, larvae and juveniles. The field experiments are limited to the cage experiments with juveniles during pile-driving. During several time periods and at different distances from the construction zone, juveniles are exposed to the sound source (pile-driving). The lab experiments consist of the playback of the recorded noise of both phases, while the different embryonic and larval developmental stages will be exposed to the recordings. The effects can be divided into (1) disturbance of development of fish eggs, (2) reduced growth rates and viability of fish larvae, (3) disturbance of natural behaviour, (4) inner ear damage, (5) tissue damage and/or mortality. The effects of the fish species will be compared and the importance of the sound parameters will be determined.
This PhD will provide information about the impact of underwater noise. Advice will be provided to the economic activities which produce underwater noise, in order to reduce their impact on the marine ecosystem. Furthermore, the results of this research will assist in the process of establishing GES noise boundaries.