Permanent Network of Innovasea Receivers Reveals COVID-19’s Impact on Fish Behavior in Australia 

For more than 15 years, researchers at Australia’s Integrated Marine Observing System (IMOS) Animal Tracking Facility have monitored large-scale movement of marine species using a permanent, nationwide array of Innovasea acoustic receivers. In 2020 they devised a new use for this network to examine COVID-19’s effect on fish behavior.

Challenge

When COVID-19 restrictions were put in place in March of 2020, researchers at IMOS wondered how the mandatory shutdown might affect marine animals. Specifically, they wanted to know if the cessation of tourist cage diving at the Neptune Islands Group Marine Park affected the behavior and space use of two resident species, white sharks and yellowtail kingfish. Typically, this type of study is best accomplished using a “before/during/after” design over a long period of time.

Solution

Enter the nationwide network of Innovasea receivers around Australia that has been collecting data on a wide variety of aquatic species for well over a decade. Specifically designed to detect changes in animal movement over time and space, the IMOS Animal Tracking Facility network provided researchers with the ideal data needed to achieve their new objective.

The team was able to examine data collected over several years from an array of Innovasea VR2AR receivers deployed at the Neptune Islands. The detections from the receivers came from 130 white sharks and 16 yellowtail kingfish that had been tagged with Innovasea’s long-lasting V16 or V13 acoustic transmitters as part of the South Australian cage diving industry monitoring program.

Result

Years after being installed, the Innovasea network provided a unique and unprecedented research opportunity. Researchers discovered that despite the significant reduction in boat visitation and associated use of food-based and sound attractants during the COVID shutdown period, the residency and weekly space use of tagged white sharks remained unchanged. There was also no change in the behavior of tagged yellowtail kingfish.

They did discover, however, that the weekly space use of yellowtail kingfish was greater when cage diving operations were active, suggesting that the fish are attracted to the boats and increase their activity by moving around and between vessels.

Australia’s Integrated Marine Observing System is enabled by the National Collaborative Research Infrastructure Strategy.