Iain C. Field

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In highly dynamic and unpredictable environments such as the Southern Ocean, species that have evolved behaviors that reduce the effects of intra-specific competition may have a selective advantage. This is particularly true when juveniles face disadvantages when foraging due to morphological or physiological limitation, which is the case for many marine(More)
The behaviour of southern elephant seals from Kerguelen Island (4950′S, 7030′E) was investigated in relation to the oceanographic regions of the Southern Ocean. The oceanographic and the seal behaviour data, including location and diving activity, were collected using a new generation of satellite-relayed devices measuring and transmitting pressure,(More)
Declines in marine predator populations have been attributed to anthropogenic activity and environmental change. Southern elephant seals Mirounga leonina are major consumers of biomass in the eastern region of the Southern Ocean and have been declining in numbers since the 1960s. Previous studies have identified evidence for habitat and diet partitioning(More)
Reproductive philopatry in bull sharks Carcharhinus leucas was investigated by comparing mitochondrial (NADH dehydrogenase subunit 4, 797 base pairs and control region genes 837 base pairs) and nuclear (three microsatellite loci) DNA of juveniles sampled from 13 river systems across northern Australia. High mitochondrial and low microsatellite genetic(More)
When resources are limited or patchy, a species may develop some degree of resource partitioning to reduce intra-specific competition. Development of intra-specific resource partitioning is more pronounced in species with clear phenotypic variation among individuals (e.g. age or sex). Southern elephant seals Mirounga leonina have pronounced sexual(More)
Marine biodiversity worldwide is under increasing threat, primarily as a result of over-harvesting, pollution and climate change. Chondrichthyan fishes (sharks, rays and chimaeras) have a perceived higher intrinsic risk of extinction compared to other fish. Direct fishing mortality has driven many declines, even though some smaller fisheries persist without(More)
We examine the structure and phylogeography of the pig-eye shark (Carcharhinus amboinensis) common in shallow coastal environments in northern Australia using two types of genetic markers, two mitochondrial (control region and NADH hydrogenase 4) and two nuclear (microsatellite and Rag 1) DNA. Two populations were defined within northern Australia on the(More)
The foraging distribution of marine predator populations is important for effective modelling and management of pelagic marine systems. We tracked 31 juvenile southern elephant seals from Macquarie Island (158°57′E, 54°30′S) over their annual post-moult and mid-year trips to sea. We calculated the amount of time spent in regional fisheries management areas(More)
Grey reef sharks (Carcharhinus amblyrhynchos) are apex predators found on many Indo-Pacific coral reefs, but little is known about their movement patterns and habitat requirements. We used acoustic telemetry to determine movements and habitat use of these sharks at the isolated Rowley Shoals atolls, 250 km off the coast of north-western Australia. We(More)
Fabien Roquet, Carl Wunsch, Gael Forget, Patrick Heimbach, Christophe Guinet, Gilles Reverdin, Jean-Benoit Charrassin, Frederic Bailleul, Daniel P. Costa, Luis A. Huckstadt, Kimberly T. Goetz, Kit M. Kovacs, Christian Lydersen, Martin Biuw, Ole A. Nøst, Horst Bornemann, Joachim Ploetz, Marthan N. Bester, Trevor McIntyre, Monica C. Muelbert, Mark A. Hindell,(More)