Identifying Reefs at Risk: Modelling Local Ecological Knowledge of a range-extending sea urchin

This project will map and model the climate driven range extension of the sea urchin Centrostephanus rodgersii along Tasmania’s east coast by utilising local ecological knowledge (LEK) obtained from commercial, recreational and research divers. With mounting pressure for more effective measures to control urchin populations due to their increasing impact on lucrative commercial species (worth over $185 million to Tasmania per annum), detailed knowledge on the extent of impact is required (Johnson et al. 2005). Assessing the impact is limited by significant temporal and spatial data gaps on the distribution and abundance of urchins; this knowledge gap being highlighted as the top research priority by multiple stakeholder groups (Tracey et al. 2014). Here we conducted semi-structured face-to-face interviews to document diver observations of urchin distribution and the extent of associated barrens in 5 m depth bands. The data will be combined with Wave Exposure Indices, environmental data and research survey data to map and model urchin distribution, abundance and barren class along Tasmania’s entire east coast. The outputs generated from this project can be utilised by management and government to implement spatial based management of various urchin control measures, with the ultimate aim of restoring reefs effected by Centrostephanus as well as preserving un-impacted reefs. Integrating LEK into marine resource management will allow a fine-scale understanding of the impact of urchins, reefs that are at future risk of degradation, and create collaborative co-management opportunities for all stakeholders implicated by the urchins in Tasmania (Worthington 2006, Stephenson et al. 2016).