What is the impact of seismic surveys on spawning and nursery grounds?
Seismic surveys, using air-guns to create a sound wave that gets reflected back off substrate rock layers, are employed as part of the suite of geophysical surveys. Unlike seismic surveys carried out by oil or gas exploration companies, the Saoirse project team only needs to know the nature of the seabed to a shallow depth. This allows them to carry out the surveys using much less impactful soundwaves.
Laboratory studies have shown limited effects on juvenile seabass as a result of exposure to seismic noise*. Other studies on the effects of seismic disturbance on the development of lobster larvae in Australia have shown no measurable negative effects with noises of up to 227 dB**.
*Radford, A. N., Lèbre, L., Lecaillon, G., Nedelec, S. L. & Simpson, S. D. (2016). Repeated exposure reduces the response to impulsive noise in European seabass. Global Change Biology, 22, 3349-3360.
**Day, R.D., McCauley, R.D., Fitzgibbon, Q.P. & Semmens, J.M. (2016). Seismic air gun exposure during early-stage embryonic development does not negatively affect spiny lobster (Jasus edwardsii) larvae. Scientific Reports, 6(1).