Potential impacts to the marine environment have been extensively considered as part of the approval process for the project.
Bait will not be intentionally applied to the marine environment however when Brodifacoum pellets are applied aerially to islands in attempts to eradicate rodents, all terrestrial habitats which may harbour rodents must receive bait. In achieving this it is often the case that a small quantity of bait enters the marine environment near the shore. On LHI it will be impossible to collect these baits. Bait entry into the lagoon will be minimised by hand baiting along the lagoon foreshore, only baiting above the high water mark and the use of a deflector arm on the spreader bucket to minimise bait entry into the water.
Studies for other island eradications, have shown that the small amounts of bait that enter the water disintegrate quickly particularly in areas with high wave action. The low-moderate application rate of Brodifacoum (0.4 g/ ha) for the LHI REP, low solubility, high dilution factor in the marine environment and one off eradication mean that any sea water contamination would be of a sufficiently low magnitude as to not present a significant risk to marine life or humans through any activity (including swimming or snorkelling).
A recent study undertaken by the University of Technology Sydney on LHI showed that even where baits enter the water, it was highly unlikely that would fish consume the pellets. The study tested fish attraction to bait at many locations around the island and found that at all sites (except for the hand feeding site at Ned’s beach) no fish consumed pellets. Even at Ned’s a very small number of individual fish consumed a pellet.