Given the interest by both the lay and scientific communities, it is surprising how little is known about the open ocean ecology of marine mammals. Their patchy distribution and low abundance leads to infrequent encounters at sea. Most of our information on marine mammals has been obtained from shipboard or aerial observations, which provide a very limited perspective on their life at or near the surface, with little insight into their behavior under the water where they spend up to 90% of their time. Recent advances in technology are providing an opportunity to gain new insights into the underwater lives of marine mammals. Preliminary information indicates that marine mammal distribution and abundance is highly correlated with oceanic features like frontal systems, thermocline depth, bathymetry, eddies, jets, and warm core rings. These features concentrate or aggregate prey, permitting effective predation. The technologies now available or under development will enable an examination of how oceanic features and processes affect marine mammal biology. This article summarizes some of the novel technologies that are currently available or under development. It is hoped that an increased awareness of the research potential of these approaches will stimulate interdisciplinary collaborations between marine mammal biologists, fisheries biologists, and physical and biological oceanographers.

Costa, D.P. 1993. The secret life of marine mammals: Novel tools for studying their behavior and biology at sea. Oceanography 6(3):120–128, https://doi.org/10.5670/oceanog.1993.07.

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