Ocean Science Consulting NZ (Asia-Pacific) Limited (OSC-NZ) recently collaborated with colleagues at JASCO Applied Sciences (JASCO) and Cawthron Institute (New Zealand) to write a detailed literature review (Lucke et al., 2019) of potential non-fishing threats faced by Hector’s (Cephalorhynchus hectori hectori) and Māui dolphin (C. h. maui). The review was commissioned by Department of Conservation (DOC) and Fisheries New Zealand (FNZ) which are currently in the process of updating their Threat Management Plan (TMP).
This literature review focussed on the ‘knowns and unknowns’ of potential impacts from Oil and Gas (O&G) production and mineral exploration on Hector’s and Māui dolphins in New Zealand waters. Overall, assessment of potential impacts on these animals was hampered by lack of information, specifically regarding effects of acoustic emissions. To fill these knowledge gaps, OSC’s review primarily consulted information from studies conducted overseas, applying knowledge from the harbour porpoise (Phocoena phocoena), a well-studied, similarly-sized, anatomically, physiologically, and ecologically-comparable species as a proxy for Hector’s and Māui dolphins.
Harbour porpoises face many potential threats in the northern hemisphere, similar to those affecting Hector’s and Māui dolphins in New Zealand waters. Particularly sounds emitted during seismic surveys and offshore pile-driving have extremely loud source levels; however, auditory information has indicated this risk to be relatively low. Other major activities, such as drilling, dredging, and vessel traffic might only pose minor risks for auditory impairment, but can have ecological implications, such as exclusion from areas where activities are occurring, and habitat destruction.
The optimal techniques to mitigate physical or behavioural effects of anthropogenic activities on Hector’s and Māui dolphins are avoidance of areas and implementation of additional buffer zones during biologically important activities, coupled with strict adherence to existing, or activity-specific monitoring and mitigation schemes when activities are permitted to occur.
DOC and FNZ need your feedback on the proposed plan to protect Hector’s and Māui dolphins. If you would like to have a say in the conservation of these animals, you’ll need to act fast as the submission deadline for responses closes at 10:00am on Monday 19th August 2019 New Zealand time.
If you would like to learn more about these sub-species, also have a look at our news article on Maui’s dolphins (here).