First tracking of the oceanic spawning migrations of Australasian short-finned eels (Anguilla australis)

Wayne M. Koster*, Kim Aarestrup, Kim Birnie-Gauvin, Ben Church, David Dawson, Jarod Lyon, Justin O'Connor, David Righton, Denis Rose, Håkan Westerberg, Ivor Stuart

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

2 Downloads (Pure)

Abstract

Anguillid eel populations have declined dramatically over the last 50 years in many regions of the world, and numerous species are now under threat. A critical life-history phase is migration from freshwater to distant oceans, culminating in a single life-time spawning event. For many anguillids, especially those in the southern hemisphere, mystery still shrouds their oceanic spawning migrations. We investigated the oceanic spawning migrations of the Australasian short-finned eel (Anguilla australis) using pop-up satellite archival tags. Eels were collected from river estuaries (38° S, 142° E) in south-eastern temperate Australia. In 2019, 16 eels were tracked for up to about 5 months, ~ 2620 km from release, and as far north as the tropical Coral Sea (22° S, 155° E) off the north-east coast of Australia. Eels from southern Australia appeared to access deep water off the Australian coast via two main routes: (i) directly east via Bass Strait, or (ii) south-east around Tasmania, which is the shortest route to deep water. Tagged eels exhibited strong diel vertical migrations, alternating between the warm euphotic zone (~ 100-300 m, 15-20 °C) at night and the mesopelagic zone (~ 700-900 m, 6-8 °C) during the day. Marine predators, probably lamnid sharks, tuna, or marine mammals, ended many eel migrations (at least ~ 30%), largely before the eels had left the Australian continental shelf. The long and risky marine migrations of Australasian eels highlight the need for better information on the processes contributing to eel mortality throughout the life cycle, including the impacts of future changes to oceanic currents, predator abundance and direct anthropogenic disturbances.
Original languageEnglish
Article number22976
JournalScientific Reports
Volume11
Number of pages13
ISSN2045-2322
DOIs
Publication statusPublished - 2021

Fingerprint

Dive into the research topics of 'First tracking of the oceanic spawning migrations of Australasian short-finned eels (<i>Anguilla australis</i>)'. Together they form a unique fingerprint.

Cite this