Coded acoustic tags and an array with moored receivers were used to study the effect of a sub‐sea AC power cable on migrating European eel, Anguilla anguilla (L.) in the Baltic Sea. Sixty eels were tagged and the migration speed was measured in a strait with a 130 kV AC power cable. Observed swimming speed over the ground was corrected for advection by the water current. Eel swimming speed was significantly lower around the cable than both north and south of the cable. No details on the behaviour during passage over the cable were possible and possible physiological mechanisms explaining the phenomenon are unknown. Further work is needed to understand the nature of the effect.
Location of Research
Bass Strait, Australia
To assess the predictions made by the Bass Strait Environment Committee:
- The species of epibiota that colonise the disturbed area over the cable are the same as those occurring in the adjacent, undisturbed habitats.
- Within two years, the epibiota that colonise the disturbed area have a composition and area of coverage similar to that of the adjacent areas.
- The magnetic fields and induced electric fields resulting from the cable during operation reflect predicted field strengths.
We conclude that the ecological effects of the cable installation on epibiota have been transient and minor for soft sediments where the cable is buried. On hard substrate the armoured cable provides a colonisable surface similar to bedrock and is quickly utilised by reef species as new habitat. Magnetic and electric fields generated by the operating cable do not appear to affect this process and within 3.5 years the armoured surface is covered with species comparable to the surrounding reef. These conclusions are consistent with other similar studies of submarine cable systems. The findings should allay some of the community concerns concerning the environmental effects of installation and operation of HVDC monopole cables with metallic return.
Sherwood, J.; Chidgey, S.; Crockett, P.; Gwyther, D.; Ho, P.; Stewart, S.; Strong, D.; Whitely, B.; Williams, A. (2016). Installation and operational effects of a HVDC submarine cable in a continental shelf setting: Bass Strait, Australia. Journal of Ocean Engineering and Sciences, 1(4), 337-353.