A global network of marine scientists is pooling research efforts to learn more about the mysterious lives of underwater creatures. The OTN will electronically tag and track thousands of marine animals with the aim of demystifying their migration patterns and providing answers to global problems such as disappearing fish stocks and climate change.
The OTN project is a Canadian initiative based at Dalhousie University in Halifax and involves scientists working in all five of the world’s oceans. This $168-million conservation mega-project is funded by the Canada Foundation for Innovation-International Joint Ventures Fund, the Natural Sciences and Engineering Research Council of Canada and the Social Sciences and Humanities Research Council of Canada.
The OTN has partnered with Australia’s Integrated Marine Observing System (IMOS) to implement the global network in this region. The OTN receivers are part of IMOS’s fully integrated national array of observing equipment which covers physical, chemical and biological variables. IMOS is responsible for deploying and servicing the OTN receivers and providing administrative and data management services.
“Canada has a leadership position in this kind of marine science,” says Tim Moltmann, Director of IMOS, the Australian partner in the project. “Canada traditionally has had a strong focus on marine technology, and the receiver technology for tracking tagged animals was developed there.”
Australian researchers have already benefited from the collaboration. In 2009, OTN funded its first acoustic sensing line outside of Canadian waters, a “listening curtain” running 60 km from Perth’s shoreline to the western edge of Australia’s continental shelf, and the first line to fully capture animal movements along the shelf.
A second 50-km line running from Tasmania’s east coast to the eastern edge of the continental shelf was installed earlier this year, and a third curtain, running 50 km east from Flinders Island in Bass Strait, will soon complete the OTN installations in Australia.
Prof Harcourt says the OTN lines “are placed at critical junctures for animal movement, at places where the mixing of water masses can act like barriers to animals.”
The IMOS Animal Tagging and Monitoring System facility, which Prof Harcourt heads up, is a collaborative network across many Australian institutions. The network has an array that detects tags from hundreds of marine animals in Australian waters each year and monitors their movements.
“The Perth line is detecting a lot of white sharks, which is one reason the line was placed where it is,” Prof Harcourt says.
“Sharks tagged in Victoria and Tasmania have been detected on the Perth line, while white sharks tagged in New Zealand have been picked up along Australia’s east coast”.
But tagging and tracking sharks is just one of many projects benefitting from the new collaboration. The grey nurse shark and the southern bluefin tuna have also been tagged as both species are listed as vulnerable, the latter being commercially harvested by Australia and Japan.
Many fish species have been tagged including snapper, blue groper and the harlequin fish as well as marine invertebrates. Giant cuttlefish and crayfish or rock lobsters are being tagged, and the data shows they migrate long distances.
IMOS’s lines pick up details about animal movements—things like the directions animals are swimming, how deep they are in the water, and the timing of their migrations. The OTN curtains are a critical component of this network and have been strategically placed to improve our understanding of animal movements around Australia’s shores.
“Oceans in the southern hemisphere are generally poorly observed compared to those in the northern hemisphere. As Australia is quite advanced in animal tracking technologies, the collaboration will benefit both IMOS and OTN through major research programs, the sharing of data, and high-level publications,” says Mr Moltmann.