Dear MARMAMers, We are pleased to announce the publication of the following paper in Current Biology:
Ultra-High Foraging Rates of Harbor Porpoises Make Them Vulnerable to Anthropogenic Disturbance Danuta Maria Wisniewska, Mark Johnson, Jonas Teilmann, Laia Rojano-Doñate, Jeanne Shearer, Signe Sveegaard, Lee A. Miller, Ursula Siebert, and Peter Teglberg Madsen URL: http://www.cell.com/current-biology/fulltext/S0960-9822(16)30314-1 DOI: http://dx.doi.org/10.1016/j.cub.2016.03.069 Highlights: · Harbor porpoises forage nearly continuously day and night to meet energy needs · Porpoises hunt up to 550 small fish prey per hour with a >90% capture success rate · Targeted sizes of fish overlap little with commercial fisheries · Even moderate disturbance may have severe fitness consequences for porpoises Summary The question of how individuals acquire and allocate resources to maximize fitness is central in evolutionary ecology. Basic information on prey selection, search effort, and capture rates are critical for understanding a predator's role in its ecosystem and for predicting its response to natural and anthropogenic disturbance. Yet, for most marine species, foraging interactions cannot be observed directly. The high costs of thermoregulation in water require that small marine mammals have elevated energy intakes compared to similar-sized terrestrial mammals. The combination of high food requirements and their position at the apex of most marine food webs may make small marine mammals particularly vulnerable to changes within the ecosystem, but the lack of detailed information about their foraging behavior often precludes an informed conservation effort. Here, we use high-resolution movement and prey echo recording tags on five wild harbor porpoises to examine foraging interactions in one of the most metabolically challenged cetacean species. We report that porpoises forage nearly continuously day and night, attempting to capture up to 550 small (3-10 cm) fish prey per hour with a remarkable prey capture success rate of >90%. Porpoises therefore target fish that are smaller than those of commercial interest, but must forage almost continually to meet their metabolic demands with such small prey, leaving little margin for compensation. Thus, for these "aquatic shrews," even a moderate level of anthropogenic disturbance in the busy shallow waters they share with humans may have severe fitness consequences at individual and population levels. For those interested in reading more, this paper and other interesting papers from our Marine Bioacoustics Lab can be downloaded from: www.marinebioacoustics.com/pub.php<http://www.marinebioacoustics.com/pub.php> Best regards, Danuta Maria Wisniewska
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