Marine biosecurity risks arising from activities/stressors within the Waikato coastal marine area

Report: TR2020/09

Authors: Lauren Fletcher and Oliva Johnston (Cawthron Institute)

Introductions of harmful marine organisms (HMOs) may have irreversible effects, including biodiversity loss and the alteration of ecosystem function. In addition, introductions may result in considerable direct economic costs, particularly with reference to high-value industries such as aquaculture and fisheries. Negative impacts to key social/cultural, amenity and public health values are also possible (i.e. impacts on food harvesting, tourism, etc.).
While most risk organisms can spread through natural dispersal mechanisms, human activities in the marine environment (e.g. vessel and equipment movements, marine farm stock transfers) can increase invasive species’ ranges by transporting them across barriers to their natural dispersal and may greatly accelerate rates of spread. A thorough understanding of all transport pathways and mechanisms of spread is critical, as unmanaged vectors have the potential to compromise the overall effectiveness of other biosecurity initiatives.

Regional councils are required to manage risks from harmful aquatic organisms through their responsibilities under the Biosecurity Act 1993, the Resource Management Act 1991 and the New Zealand Coastal Policy Statement 2010. A wide range of activities within the Waikato Coastal Marine Area (CMA) have implications for marine biosecurity. In managing these
activities, it is important that biosecurity risks are recognised and mitigated at the earliest stage possible. In order to implement appropriate management responses, the context and magnitude of biosecurity risk associated with human activities need to be understood. This includes whether the activity introduces biosecurity risks that arise from outside the region, is likely to lead to novel biosecurity risks to the region, and the likely importance of the activity in the context of other controlled and uncontrolled activities. This report provides an overview of marine biosecurity issues relevant to a range of coastal activities, with specific appraisal of risks to the Waikato CMA. This report is intended as a resource that WRC staff can utilise for assessing marine biosecurity risks by linking certain activities with potential impacts and mitigation options.