Planning for Underwater Anthropogenic Noise in New Zealand's Coastal Marine Area

Human activities in the marine environment, such as shipping, mineral and petroleum exploration, dredging and construction are known to produce underwater noise. Underwater anthropogenic noise can cause behavioural changes, injury and mortality in marine mammals, fish and marine invertebrates and is likely to have long-term impacts on marine animal populations. To reduce environmental effects, spatial planning for underwater noise has been proposed but has only rarely occurred. In New Zealand, regional councils are responsible for planning for underwater noise in the Coastal Marine Area. However, regional coastal plans have been criticised for not considering underwater noise. Therefore, this research aimed to: (1) discern the current approaches of regional councils to underwater anthropogenic noise and to ascertain the reasons for those approaches, and (2) identify areas of both high marine biodiversity and high underwater noise to inform spatial planning for underwater noise. Results revealed that 14 of 17 regional coastal plans do not refer to underwater noise and that general noise provisions in these plans were intended to manage above-water noise, not underwater noise. Only Auckland Council has underwater noise provisions with rules and a permitted underwater noise limit. The main factors for the absence of provisions appear to be the age of regional coastal plans and a lack of awareness of underwater noise as an issue. Results also indicated that without underwater noise provisions councils can still manage the effects of underwater noise through unrelated, high-level provisions or through the Resource Management Act, however only a small number (38%) are doing so. Some councils expressed an interest in developing underwater noise provisions including permitted noise limits but a lack of expertise and resources in councils were considered obstacles to provision development. It is concluded that central government guidance and assistance from external agencies is needed to overcome these obstacles. However, a permitted noise limit of 180 dB re 1 μPa is proposed for inclusion in provisions. To inform spatial planning for underwater noise, regions with high regional biodiversity and with localised biodiversity 'hotspots' for seven marine taxa were identified. Eleven regions were also identified as either high or low underwater noise environments. Areas with both high underwater noise and high biodiversity for the taxa were then identified. Provisions, including rules, for these areas are suggested. It is argued that provisions and spatial zones based on these results could be included in regional coastal plans to manage underwater anthropogenic noise