Research Technical Report

Environmental Impact of a Submarine Cable: Case Study of the ATOC/Pioneer Seamount Cable

Kogan, I., C.K. Paull, L. Kuhnz, S. von Thun, E. Burton, H.G. Greene, and J.P. Barry (March 2004)

Poster presentation at the Sanctuary Currents Symposium, Seaside, CA

ABSTRACT

To better understand the potential impacts of cables on the seabed, a study of the environmental impacts of the ATOC/Pioneer Seamount cable was conducted. The condition of the cable, its effect on the seafloor, and its effect on benthic megafauna and infauna were determined. The 95 km long cable extends between Pioneer Seamount and Half Moon Bay, California. Most of the cable has become buried in continental shelf sediment substrates whereas much of the cable remains exposed in deeper depths. The cable is also exposed in nearshore rocky environments and on Pioneer Seamount. Evidence of cable and rock abrasion was seen in the nearshore rocky region. Neither the rocks nor the cable appeared damaged on Pioneer Seamount. Several sharp kinks in the cable were seen in an area subjected to intense trawling activity. The main biological features associated with the cable were organisms utilizing it as substrate and occasionally as shelter. Few differences were found between cable and control sites at the 95% confidence level. The cable may have a subtle local hydrodynamic effect. Coarse extrapolation of the transect data suggest that ~500,000 organisms may live on or near the cable.