Sound impact on fish populations
The first of April was the official start of Phase II of the collaborative “PCAD4Cod”-project on the effect of sound on fish populations. Hans Slabbekoorn, associate professor at the IBL, is the principal investigator and collaborates with three PhD-students, Dr. Erwin Winter, (Wageningen Marine Research), Dr. Jan Reubens (Flandres Marine Institute) and several international experts. The Joint Industry Programme on E&P Sound and Marine Life invested € 2.000.000 into the project for the coming two years.
Seismic survey sound pollution
Seismic surveys are necessary to explore the floor of seas and oceans but yield potential conflict with aquatic life. Seismic surveys involve a sound source and produce long series of loud sounds, with a seismic pulse about every 10 seconds, for hours in a row, potentially 24/7, over periods from several days to months. These acoustic exercises are essential for extracting geological information about what is under the seabed, for example to get insight into the size and location of oil and gas resources.
Acoustic conflict with hearing fish
However, humans are not alone in the exploitation of sonic information. Visibility in the marine environment is typically low and water is an excellent medium for sound propagation. Consequently, many aquatic animals can hear well and rely on sound for many daily activities that are critical for survival and reproduction. Hence there is potential for acoustic conflict and there may be detrimental effects on aquatic life, including many species of fish.
Four project components
The project includes an integrated set of studies. Existing and new field data will be used in models of energy-flow, individual behaviour and population dynamics (component I). Field data will be collected on tagged, free-ranging fish in the North Sea exposed to an experimental but real-size seismic survey in open water (component II) and on behavioural and physiological responses of adult and juvenile, captive fish in an outdoor floating pen (component III). Sound field properties will be measured and modelled in terms of sound pressure and particle motion for both types of field studies (component IV).
The project components are shaped by the insights of the phase I theoretical study as conducted in the context of request for proposals on Establishing the Sensitivity of Fish to Seismic Activities from the Joint Industry Programme. One of the main outcomes of the theoretical study was the notion that the most effective way to make progress in understanding potential effects of seismic surveys would be through complementary efforts in modelling and data collection. The impact on behaviour and physiology will be investigated for a single model species, Atlantic cod (Gadus morhua) using a Population Consequences of Acoustic Disturbance (PCAD)-framework, hence the name PCAD4Cod.