The effect of seismic surveys on catch rates of rock lobsters in western Victoria, Australia

The effect of seismic discharges on rock lobsters was investigated through statistical analysis of the coincidence between seismic surveys and changes in commercial catch rates in western Victoria between 1978 and 2004. In 12 depth-stratified regions, the number of acoustic pulses during seismic surveys was correlated with catch per unit effort (CPUE) of rock lobsters to determine whether catch rates were affected in the years following seismic surveys. In three regions subject to intensive seismic surveys two-way analysis of variance was used to detect short-term (weekly) changes in CPUE before, during and after these seismic surveys.There was no evidence that catch rates of rock lobsters in western Victoria were affected by seismic surveys in the weeks or years following the surveys. However, most seismic surveys occurred in deep water, where impacts would be expected to be minimal. The sensitivity of analyses in shallow water was generally limited by low levels of seismic surveying, but in one region where there was intensive seismic activity, the sensitivity was limited by the low abundance of rock lobsters. The apparent lack of impact of seismic surveys on catch rates of rock lobsters is consistent with the limited information available on the physiological effects of seismic surveys on invertebrates, including rock lobsters.