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10.07.2015 04:17 Age: 2 yrs
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Marine animal tracking featured in ‘Science’

Hi-tech tracking tags are redefining how we discover, understand and manage ocean life.

Weddell seals. Image: Rob Harcourt

Researchers have long attempted to follow animals as they move through their environment. Until relatively recently, however, such efforts were limited to short distances and times in species large enough to carry large batteries and transmitters. New technologies have opened up new frontiers in animal tracking remote data collection.

A new paper, published in Science, details the explosion in aquatic animal tracking research over the past 30 years and its impact on discoveries about the movements, migrations, interactions and survival of both common and elusive aquatic species.

The review describes a profound revolution, including over 20 examples of scientific breakthroughs, in global ocean observation science achieved through advancements in acoustic and satellite telemetry—tracking via electronic tags placed on organisms ranging from tiny neonate fish to large whales, which transmit data to fixed or mobile receiver stations or orbiting satellites.

Electronic tags can now weigh less than a penny, can transmit for more than 10 years, and can be attached to almost any species, at any life stage, to collect high-resolution data in four dimensions (2D-horizontal, depth and time).

“The vastness and impenetrability of the ocean has historically limited our ability to acquire and process information on animal movements. Telemetry has significantly enhanced our capacity to predict and plan in the face of climate change and human influence,” said Sara Iverson, scientific director of the Ocean Tracking Network and corresponding author on the paper.

Professor Rob Harcourt from Macquarie University, leader of the IMOS Animal Tracking Facility and one of the authors of the study said: “Telemetry has truly opened a window into the underwater world. The information transmitted by a suite of aquatic animals from tiny jellyfish weighing only grams, to the largest animals ever to have roamed the earth, the blue whale, has completely rewritten the textbooks. We now know they dive deeper, for longer, swim further and exploit seemingly impenetrable depths.”

The IMOS Animal Tracking and Monitoring System was featured as an array that monitors across an entire country coastline. IMOS leads the Southern Hemisphere section of an internationally coordinated Ocean Tracking Network (OTN) Marine Animal Tracking program.

Telemetry data have revealed the often-mysterious migrations of endangered marine animals like leatherback turtles, basking sharks, European eels and Pacific bluefin tuna. These discoveries, and the increasingly sophisticated technology behind them, generate critical knowledge towards conservation recommendations. Tracking studies also pinpoint successes and limitations of current management plans. For example, acoustically tagged reef fish were shown to regularly move outside their Marine Protected Area, putting them at risk.

“In the future, we could be looking at spatially dynamic MPAs, which move annually with predictions of animals’ response to their environments,” said Nigel Hussey, lead author and researcher at the University of Windsor with the Ocean Tracking Network.

Acoustic and satellite telemetry studies are being combined with other biological measurements like genetic analysis or physiological status. These data help determine drivers behind animal behaviour to forecast how anthropogenic and climate changes will affect species and populations.

Aquatic animal movements and migrations transcend geopolitical, economic, and management boundaries. Telemetry studies in the last decade have documented movement over transoceanic scales, to regions unreachable by humans, and into some of the harshest parts of the ocean, providing the groundwork for “next-generation aquatic governance frameworks.”

“The ocean will continue to change,” said Hussey. “Global collaboration—among industry and science sectors, and researchers themselves—is imperative to get ahead of these changes before they catch up to us.”

Ocean Tracking Network is a $168-million research and technology development platform headquartered at Dalhousie University, in Halifax, Nova Scotia. Starting in 2008, OTN began deploying Canadian state of the art acoustic receivers and oceanographic monitoring equipment in key ocean locations. These are being used to document the movements and survival of marine animals carrying acoustic tags and to document how both are influenced by oceanographic conditions.

OTN is funded by the Canada Foundation for Innovation and the Natural Sciences and Engineering Research Council of Canada, with additional support from the Social Sciences and Humanities Research Council of Canada and the Nova Scotia Research and Innovation Trust.