Motivation and harvesting behaviour of fishers in a specialized fishery targeting a top predator species at risk

Effective management of wildlife resources depends on understanding and cooperating with the human users of the resource, particularly as policies may be rejected if user satisfactions are not met. In Australia, recreational anglers can legally target a migratory top predator, the shortfin mako shark (Isurus oxyrinchus), that is also a species at risk. It is assumed that most of the sharks are released and population remains minimally impacted; yet, the actual release rate of this species is unknown and little information is available on the motivations and satisfactions of anglers that participate in this fishery. The rate of catch-and-release fishing was ascertained by a web survey of recreational shark anglers from three south-eastern Australian states. Respondents reported that ~70% of the captured makos were released, with significant geographic variation in release rates between states. Differences in harvesting behaviour between states could be attributed to the varying value assigned to shortfin mako as a sport fish and table fish among regions. Additionally, higher rates of release among anglers from New South Wales may be linked to increased opportunity for resource substitution (i.e. greater diversity of game fish species) and established norms driven by current catch-and-release fisheries in that region. Increased participation in catch-and-release fishing may be achieved by establishing behavioural norms by the provision of more desirable incentives to release sharks during fishing competitions. Data on regional variation in release rates yields important information for managers to target specialized fishers to incentivize catch-and-release fishing with an objective of changing behaviour. Information on natural resource user motivations and satisfactions, such as studied here, has the potential to guide management actions and the ways in which managers interact with resource users.