No matter what the size, shape or means of propulsion of a marine animal, from whale to seabird they all travel through or above the ocean following similar patterns, according to a “first-of-its-kind” Australian study.
Researchers from the University of Western Australia and Australian Institute of Marine Science have analysed results of a worldwide collaborative project called the Marine Megafauna Movement Analytical Program (MMMAP).
This looked at the speed and movement patterns of more than 2500 tagged marine animals from 50 species, tracked by satellite during the past 30 years.
Among terrestrial species, movement tends to be linked to body size; but the team was surprised to find that unrelated marine species such as whales, sharks, polar bears and seabirds all displayed similar movement patterns.
What differences there were across all species were linked to their destinations, and thought to be related to the way in which they used various marine habitats.
Movement in open ocean among these “fellow-travellers” was usually directed straight towards a key location, whereas animals close to shore, potentially in search of food or protection, were more likely to adapt their behaviour.
“Inshore habitats such as reefs and seagrass are generally more complex compared to open-ocean habitats offshore, and are therefore stimulating more complex movement patterns in these animals,” said report co-author Dr Michele Thums.
The animals’ shared ability to suit behaviour to habitat offered hope that they would be more resilient to rapidly changing coastal environments than might have been expected, say the researchers.
While the results of the study suggested that marine species had adapted to different properties of both the inshore and offshore marine environment, it remained important to understand how, and how fast, they were able to adapt, said lead author Dr Ana Sequeira.
“This is particularly important to guide conservation-management, in view of the forecast severe ocean changes, including sea-level rise and reduced Arctic sea-ice cover,” she said.
The report is published in PNAS, and the team now plan to investigate global interactions between marine megafauna and shipping.
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02-Mar-18
