Top shelf bottom feeders: food provisioning in stingrays

Recreational anglers often discard fish waste back into waterways, yet the effects of incidental provisioning as a result of this activity have not yet been assessed, and are not considered in management. At the Woollamia boat ramp in Jervis Bay, Australia, anglers have provisioned short-tail stingrays since 1985. In Chapter 1, we compared stingray visitation with provisioning activity, which indicated their movements are strongly linked to provisioning. Observations also suggest the area may have reproductive significance to this species. Short-tail stingrays may be capable of complex social behaviours, yet no assessment of their sociality exists. Aggregation at the provisioning site provided an opportunity to study their social behaviour. In Chapter 2, we assessed dyadic agonistic interactions and observed a dominance hierarchy and social network that was reflective of a despotic society, indicating this species is capable of highly complex social behaviour. These stingrays may be at risk of experiencing further negative impacts from provisioning, such as dependency, resulting in reduced fitness. The results of these studies highlight that management of recreational fisheries, with respect to appropriately handling waste and its potential impacts on wildlife, needs to be revised. Our data provide a baseline of effects on which monitoring and management programs can be built.