Standard Presentation Australian Marine Sciences Association Annual Meeting 2023

Could stingrays be effective ecological indicators for coastal environments? (#247)

Jaelen N Myers 1 , Michael Bradley 1 , Adam Barnett 2 , Carlo Mattone 1 , Marcus Sheaves 1
  1. James Cook University, Douglas, QLD, Australia
  2. James Cook University, Cairns, QLD, Australia

Coastal habitats are valuable nursery grounds for several elasmobranch taxa but are increasingly threatened by anthropogenic activities. Coastal rays are one of the fastest declining vertebrate groups in the world. With vital trophic roles as mesopredators, declining populations or localised extinctions may cause reduced ecosystem function and stability. There is a growing need to manage at-risk species and identify indicators of broader ecosystem health, but only a few species have been labelled as indicators due to insufficient data. Identifying which habitats support high ray abundances and understanding how these spaces are used is necessary for bridging this gap. Drones can cover large areas while minimising cost and effort, making them ideal tools for investigating habitat use in biologically valuable areas. Results from my drone surveys of intertidal flats of North Queensland has shown rays are abundant in these environments, and some species are tightly associated with specific habitats. For instance, juvenile Urogymnus granulatus (IUCN listing vulnerable), were found exclusively near mangroves, suggesting their presence could be an indicator of mangrove ecosystem health. Drone surveys also allow for direct observations of behaviour to provide insights on real-time habitat use. My results support that intertidal habitats are profitable feeding grounds for juvenile rays. Thus, abundances are likely dependent on benthic prey distributions, and in turn, habitats that provide these resources. Adopting remote sensing technology for short and long-term monitoring of elasmobranchs will continue to be valuable for understanding factors that influence species abundances and assessing their potential as ecological indicators.