There was a time when researchers wanting to track the pathways or favored places of migratory marine species, particularly those that traveled far offshore, had little to go on but intuition and scattered observations at various points along those species' migration routes. Over the last couple of decades, however, that has changed with the growth of satellite telemetry, otherwise known as biologging - or, as Sara Maxwell of the Marine Conservation Institute describes it, "the science of attaching things to animals and seeing where they go."
Speaking at the second International Marine Conservation Congress in Victoria, British Columbia, Maxwell described a study in which she and several colleagues searched a total of 93 conservation and ecology journals for articles that detailed biologging research on marine wildlife. They found that the majority of the research articles described satellite tagging of sea turtles - understandably so, given the vast distances that sea turtles travel out in to the open ocean, and the great lengths of time they spend there. The next largest subset was devoted to seabirds, and the remainder to marine mammals.
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However, Maxwell observed, relatively few of those studies truly quantified their findings in a way that could be of direct use in management purposes - for example, in determining the overlay between turtle hotspots and regions of heavy fishing. Eighty percent of the papers in the ecology journals were "pure" science, with little or no management or conservation perspective at all. Which is not to say, she emphasized, that there is anything inherently wrong with science for science's sake; however, she encouraged researchers to take several steps to help their biologging studies have more practical, real-world applications, including combining telemetry datasets with other researchers and communicating their findings with managers, stakeholders and non-governmental organizations.
Hoyt Peckham of the Grupo Tortuguero de las Californias was more direct.
Peckham noted that affixing satellite transmitters to wildlife was costly, in terms of the dollar amounts involved and also the potential stress and other impacts on the animals concerned; in the case of rare and endangered animals, the process could be negatively affecting a high proportion of vulnerable populations, he pointed out.
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"We need to think through: 'Is it justifiable?' If you can't fully justify telemetry, don't do it," he said.
Peckham, nowadays a reluctant tagger, nonetheless did use the technique recently to demonstrate the existence of a loggerhead turtle hot spot off Baja California Sur; he did so, he pointed out, in conjunction with local fishermen whose fleets were catching thousands of turtles a year, and although his technique could be seen as particularly invasive - it involved fishermen participating in the tagging and even keeping tagged turtles in their homes overnight before releasing them - it succeeded in its aim of creating a kind of kinship with the turtles on the locals' part and resulted in a dramatic change of fishing practices that eliminated the turtle bycatch.
Matthew Witt of the University of Exeter told IMCC about a project that, while less obviously dramatic in its impacts than Peckham's, did clearly show the potential conservation benefits of biologging. By affixing transmitters to female leatherback turtles as they set out into the Atlantic after nesting on the beaches of Gabon in central west Africa, Witt and colleagues were able to ascertain that the turtles spend the subsequent several years at sea in one of three areas: the central equatorial Atlantic; off the Atlantic coast of South America; and off the waters off South Africa, where they mingle with turtles from the Indian Ocean. By overlaying that information with data of anthropogenic threats including fisheries, Witt and colleagues are able to devise management plans that involve limiting human activity in those areas that are turtle hot spots.
More immediately, Witt described tagging nesting females as they nested on beaches, and spent several days in coastal waters between nesting spells, in adjoining marine reserves in Gabon and Congo. The satellite data showed a far greater occurrence of turtles off Gabon - where the reserve was strictly enforced - and directly across the border line in Congolese waters, where restrictions were looser, enforcement less strict, and fishing prevalent. As a direct result of the findings, the two governments agreed to create a trans-boundary marine protected area that provides greater protection for turtles and is more biologically relevant for other marine species, and which shows, said Witt, "that telemetry can link species and threats" in a way that can provide strong conservation benefits.
Photograph of leatherback turtle, laying eggs prior to being tagged, by Steve Garvie, via Wikimedia Commons.
Tags: Amphibians and Reptiles, Animal Breeding, Animal Science, Conservation, Scientific Discoveries
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