Collaborative approaches to accessing and utilising historical citizen science data: a case-study with spearfishers from eastern Australia

Scientists are increasingly utilising non-traditional data to assist with defining biological baselines and for monitoring environmental change. These data present challenges not encountered with traditional, fit-for-purpose scientific data, including engaging with data owners, building trust and maintaining relationships, analysing and interpreting data collected under varying methodologies, and the possibility that data may not suit an intended purpose. Here we describe engagement activities undertaken with recreational spearfishers to collate and examine spearfishing club data collected from competitions held throughout south-eastern Australia from the 1960s until the present, representing one of the most extensive citizen science datasets for marine species in the region. The data proved suitable for demonstrating change in coastal fish communities, some of which were consistent with expectations given a warming climate over the period considered. With an attitudinal survey of divers we also asked about their experience of environmental change, and interaction with management over recent decades. Mutually beneficial outcomes include: collating and archiving significant data that may otherwise have been lost; improved understanding of spearfisher concerns and experiences; improved engagement between collaborators; and recognition of spearfishers' desire for better engagement in science and management. Lessons learnt may be broadly applicable to improving collaboration between recreational fishers, citizen science groups, researchers and managers.