Recreational fishery discard practices influence use of tidal estuary by a large marine mesopredator

Abstract

Context. It is common for recreational anglers to discard waste produced from filleting catches back into the water, which results in a highly spatio-temporally predictable food subsidy for wildlife to scavenge. However, the behavioural responses of these scavengers has received little attention. Aims. We aimed to assess the visitation of a common mesopredatory scavenger in relation to temporal patterns in waste discarding at a boat ramp in south-eastern Australia. Methods. Using passive acoustic telemetry, the movements of 13 adult female smooth stingrays (Bathytoshia brevicaudata) were tracked, and patterns in their acoustic detections and duration of time spent in different sections within the study area were compared. Key results. Use of the study area was strongly focused around the boat ramp, and peaked during periods of increased provisioning activity (i.e. afternoons and weekends). Environmental variables had limited influence on visitation, suggesting that the use of the area was not likely to be linked to natural behaviours. Conclusions. The observed patterns indicated that the movements of smooth stingrays were linked to waste-discard practices by recreational anglers. Implications. This study has implications for the management of discard practices for recreational fishing.

Diving into the diet of provisioned smooth stingrays using stable isotope analysis

“…Similarly, at Bendalong, approximately 25 km south of Jervis Bay, smooth stingrays forage recreational fish cleaning scraps but have also become the target of an unregulated tourism attraction where tourists hand‐feed the stingrays either scraps from recreational anglers or purchased baits (usually pelagic pilchards). Research has indicated that the stingrays use of these sites is strongly linked to fish cleaning activity (Pini‐Fitzsimmons et al ., 2018, 2023; Pini‐Fitzsimmons, unpub. data.).…”