 Coastal surveillance cameras are also fitted along these fences to observe any suspicious or illegal movement.By the end of December in 2003, the total length of coastal fencing had reached 24.7 kilometres, although there were some protests over the potential environmental hazards the fencing may pose to natural amphibious species, particularly on Pulau Ubin and Singapore's northwestern shoreline.The PCG attempted to allay these fears by informing that the fencing is constructed in such a manner to allow small animals to pass below it safely.