51. Drivers of concentrated predation in an Antarctic marginal-ice-zone food web
- Author
-
Benjamin Saenz, Erin Conlisk, Kendra L. Daly, David G. Ainley, Grant Ballard, Megan Elrod, and Stacy Kim
- Subjects
0106 biological sciences ,Krill ,Food Chain ,010504 meteorology & atmospheric sciences ,Euphausia ,Ecosystem ecology ,Antarctic Regions ,lcsh:Medicine ,01 natural sciences ,Models, Biological ,Article ,Predation ,Animals ,lcsh:Science ,0105 earth and related environmental sciences ,Trophic level ,Marine biology ,Multidisciplinary ,biology ,010604 marine biology & hydrobiology ,Fur Seals ,lcsh:R ,Whales ,Food webs ,biology.organism_classification ,Spheniscidae ,Food web ,Perciformes ,Oceanography ,Fast ice ,Habitat ,Predatory Behavior ,Antarctic silverfish ,Environmental science ,lcsh:Q ,Euphausiacea - Abstract
Predators impact preyscapes (3-D distribution of forage species) by consuming prey according to their abilities or by altering prey behavior as they avoid being consumed. We elucidate prey (Antarctic silverfish[Pleuragramma antarctica] and crystal krill[Euphausia chrystallorophias]) responses to predation associated with the marginal ice zone (MIZ) of the McMurdo Sound, Antarctica, polynya. Prey abundance and habitat was sampled across a 30 × 15 km area by remotely-operated vehicle, and included locations that were accessible (ice edge) or inaccessible (solid fast ice) to air-breathing predators. Prey and habitat sampling coincided with bio-logging of Adélie penguins and observations of other air-breathing predators (penguins, seals, and whales), all of which were competing for the same prey. Adélie penguins dived deeper, and more frequently, near the ice edge. Lowered abundance of krill at the ice edge indicated they were depleted or were responding to increased predation and/or higher light levels along the ice edge. Penguin diet shifted increasingly to silverfish from krill during sampling, and was correlated with the arrival of krill-eating whales. Behaviorally-mediated, high trophic transfer characterizes the McMurdo Sound MIZ, and likely other MIZs, warranting more specific consideration in food web models and conservation efforts.
- Published
- 2020