Killer whales are diving to record depths to pinch expensive catch from commercial fishing lines, expanding their role as an apex predator to the very depths of the ocean, Deakin researchers have found.

December 3, 2018

Dr Paul Tixier, a research fellow at Deakin’s Centre for Integrative Ecologywithin the School of Life and Environmental Sciences, is part of the research team that made the discovery while monitoring the dive behaviour of a killer whale (Orcinus orca) in subantarctic waters in South Georgia.

Researchers used satellite-linked location and dive-profile tags on the killer whale, which was taking Patagonian toothfish from commercial longlines – a fishing technique using a long line with baited hooks to capture target fish.

Patagonian toothfish are a deep-water fish and are considered a delicacy, with the majority of the fish caught legally by Australian boats sold overseas to Japanese, Chinese and US markets.

Dr Tixier said the results were striking, with the killer whale diving to 1087 metres – the greatest depth ever recorded for that species and around 300 metres deeper than previously recorded.

“The diving ability of the species has been underestimated, but we found the whales were diving significantly deeper and faster when taking from fishing lines compared to when foraging naturally,” he said . . . 

To read the FULL article please visit the Source Deakin.edu.au

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