01745nas a2200205   4500008004100000022001400041245012000055210006900175260001600244300001600260490000800276520107300284100003001357700002601387700001501413700001901428700002001447700002101467856005101488       2018                        eng d  a0001-496600aRelationship between cetacean presence, their prey, and oceanographic conditions at an offshore pelagic environment0 aRelationship between cetacean presence their prey and oceanograp  cJan-09-2018  a1921 - 19210 v1443 a<p>Large mobile predators take advantage of offshore pelagic environments that tend to be surveyed at a low temporal scale. We present results from a one-year observation of passive and active acoustics, as well as oceanographic measures, taken at a moored location 150 nmi offshore southern California in 4000 m deep pelagic waters. The passive acoustic data shows presence of delphinids and baleen, sperm, and beaked whales throughout the recording period with species-specific seasonal occurrence. Variability in small pelagics, krill, and diel vertical migrators is evident from the active acoustic data. Multiple upwelling events and associated changes in dissolved oxygen at 500 m water depth, as well as in surface waters, were also recorded over the year. We will present results on the relationships among oceanographic variability, presence of pelagic species, and top predator presence. This study will provide valuable information on ecosystem processes in meso- and epipelagic waters on a relatively small spatial scale but very fine temporal scale.</p>
1 aBaumann-Pickering, Simone1 aTrickey, Jennifer, S.1 aRice, Ally1 aŠirović, Ana1 aRenfree, Josiah1 aDemer, David, A.  uhttp://asa.scitation.org/doi/10.1121/1.506841301815nas a2200169   4500008004100000022001400041245006400055210006300119260001600182300001600198490000800214520130400222100001901526700003001545700001901575856005101594       2018                        eng d  a0001-496600aPredator-prey interactions in the Southern California Bight0 aPredatorprey interactions in the Southern California Bight  cJan-09-2018  a1921 - 19210 v1443 a<p>The Southern California Bight (SCB) is an important foraging area for a variety of cetacean species, including blue whales and beaked whales. However, the interactions of these species with their prey (krill and deep-water squid, respectively) can be very difficult to observe. Moorings combining passive and active acoustics were deployed at two locations in the SCB in two consecutive fall and winter seasons. A High-frequency Acoustic Recording Package sampling at 200 kHz recorded the full range of baleen and beaked whale signals. The active acoustic system on each mooring included two Simrad Wide Band Acoustic Transceivers (WBAT). A bottom-mounted WBAT had an upward looking 70 kHz transducer and the one at 300 m depth had upward looking 70 kHz and 200 kHz transducers. Over the course of four months, blue whale songs and social calls were recorded on both moorings. Beaked whale echolocation clicks were commonly detected on the mooring deployed offshore, with only rare beaked whale encounters on the coastal mooring. Backscatter data indicated overlap in the presence of cetacean predators and their prey. Scattering layer dynamics were dominated by regular diel migration, with differences in scatterer abundance between mooring sites, as well as on 2&ndash;5 day time scales.</p>
1 aŠirović, Ana1 aBaumann-Pickering, Simone1 aWarren, Joseph  uhttp://asa.scitation.org/doi/10.1121/1.5068414