Unique Sequence of Events Triggers Manta Ray Feeding Frenzy in the Southern Great Barrier Reef, Australia

Remote Sensing

Scarla J. Weeks⁴  Marites M. Magno-Canto⁴  Fabrice R. A. Jaine⁴  Jon Brodie³  Anthony J. Richardson¹  Raphael M. Kudela² 

[1] Oceans and Atmosphere Flagship, CSIRO Marine and Atmospheric Research, EcoSciences Precinct, Dutton Park, Brisbane, QLD 4102, Australia; E-Mail:Biophysical Oceanography Group, School of Geography, Planning and Environmental Management, The University of Queensland, St Lucia, QLD 4072, Australia;;Centre for Tropical Water and Aquatic Ecosystem Research, James Cook University, Townsville, QLD 4811, Australia; E-Mail:;Biophysical Oceanography Group, School of Geography, Planning and Environmental Management, The University of Queensland, St Lucia, QLD 4072, Australia; E-Mails:

关键词: remote sensing;    manta rays;    frontal zones;    sea surface temperature;    chlorophyll;    photic depth;    eddy dynamics;    river discharge;    upwelling;    Great Barrier Reef;   

DOI  :  10.3390/rs70303138

来源: mdpi

【 摘 要 】

Manta rays are classified as Vulnerable to Extinction on the IUCN Red List for Threatened Species. In Australia, a key aggregation site for reef manta rays is Lady Elliot Island (LEI) on the Great Barrier Reef, ~7 km from the shelf edge. Here, we investigate the environmental processes that triggered the largest manta ray feeding aggregation yet observed in Australia, in early 2013. We use MODIS sea surface temperature (SST), chlorophyll-a concentration and photic depth data, together with in situ data, to show that anomalous river discharges led to high chlorophyll (anomalies: 10–15 mg∙m⁻³) and turbid (photic depth anomalies: −15 m) river plumes extending out to LEI, and that these became entrained offshore around the periphery of an active cyclonic eddy. Eddy dynamics led to cold bottom intrusions along the shelf edge (6 °C temperature decrease), and at LEI (5 °C temperature decrease). Strongest SST gradients (>1 °C∙km⁻¹) were at the convergent frontal zone between the shelf and eddy-influenced waters, directly overlying LEI. Here, the front intensified on the spring ebb tide to attract and shape the aggregation pattern of foraging manta rays. Future research could focus on mapping the probability and persistence of these ecologically significant frontal zones via remote sensing to aid the management and conservation of marine species.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.