FRIDAY MORNING, 2 DECEMBER 2016 CORAL 2, 8:00 A.M. TO 11:45 A.M. Session 5aAB Animal Bioacoustics: Marine Acoustic Ecology Jennifer L. Miksis-Olds, Chair Center for Coastal and Ocean Mapping, Univ. of New Hampshire, 24 Colovos Rd., Durham, NC 03824 Contributed Papers 8:00 8:30 5aAB1. A multi-year time series of marine mammal distribution in the 5aAB3. Did humpback whales go missing off Maui, Hawaii? A compari- Alaskan Arctic. Jessica Crance and Catherine Berchok (AFSC/NMFS/ son of song activity between the 2014/15 and 2015/16 breeding seasons. NOAA, National Marine Mammal Lab., 7600 Sand Point Way NE, Seattle, Anke Kugler€ (Marine Biology Graduate Program, Univ. of Hawaii at WA 98115, [email protected]) Manoa, 2525 Correa Rd. HIG 132, Honolulu, HI 96822, akuegler@hawaii. edu), Marc O. Lammers (Hawaii Inst. of Marine Biology, Univ. of Hawaii The Marine Mammal Laboratory has deployed long-term, moored, pas- at Manoa, Kaneohe, HI), Eden J. Zang (Oceanwide Sci. Inst., Honolulu, sive acoustic recorders at numerous locations in the Alaskan Arctic since HI), Maxwell B. Kaplan, and T A. Mooney (Woods Hole Oceanographic the BOEM-funded Chukchi Acoustics, Oceanography, and Zooplankton Inst., Woods Hole, MA) (CHAOZ) study began in 2010. These instruments, often collocated with oceanographic instruments, collect year-round passive acoustic data (16 Each winter, thousands of humpback whales (Megaptera novaeangliae) kHz sampling rate, ~30% duty cycle). All acoustic recordings (100%) were migrate from their high latitude feeding grounds in Alaska to mate and calve analyzed using an in-house Matlab-based manual analysis program for 12 in the shallow tropical waters around the Main Hawaiian Islands. Population different Arctic and sub-Arctic cetacean and pinniped species, as well as for estimates suggest that up to 10,000 animals winter in Hawaiian waters, vessel, seismic airgun, and ice noise. Bowhead and beluga distributions making up more than half of the total North Pacific stock. However, in the showed similar patterns, with bimodal temporal distributions representing 2015/16 season, anecdotal reports from commercial operators and researchers the fall and spring migrations. Infrequent gray whale detections (isolated on tell of an unusually low number of whales compared to previous years off the nearshore recorders) followed a similar, albeit less defined, bimodal distri- island of Maui. To examine this issue, data from long-term passive acoustic bution. Walrus and bearded seal calls were detected almost year-round, with monitoring with autonomous Ecological Acoustic Recorders (EARs) during peak bearded seal calling from April through June. Detections of sub-Arctic the 2014/15 and 2015/16 seasons off the west coast of Maui were analyzed species (e.g., humpback, fin, killer, and minke whales) were rare north of using male chorusing levels as a proxy for relative whale abundance. Root- 70 N. Correlation of marine mammal distribution with concurrent oceano- mean-square sound pressure levels (SPLs) were calculated to compare low graphic parameters revealed strong associations with oceanographic and frequency acoustic energy (0-1.56 kHz) between both seasons. The data prey variables, more specifically, ice concentration and thickness, chloro- showed that chorusing levels dropped in early January 2016. Although levels phyll, wind speed, and currents. This study illustrates the importance of col- subsequently increased again until they peaked in February as expected, SPLs lecting concurrent long-term passive acoustic and oceanographic data in a remained lower than in 2014/15 throughout the remaining season. These rapidly changing environment. results suggest that the number of singing males was indeed lower during the 2015/16 season off west Maui and that future monitoring is warranted. 8:15 8:45 5aAB2. A preliminary acoustic survey of echolocating marine mammals in the Bering Sea. Kerri Seger (CCOM, Univ. of New Hampshire, 9331 5aAB4. How reliable is song as a cue for acoustic surveys of humpback Discovery Way, Apt. C, La Jolla, CA 92037, [email protected]), Jennifer whales (Megaptera novaeangliae) with changing population size and Miksis-Olds (CCOM, Univ. of New Hampshire, Durham, NH), and Bruce density? Michael J. Noad, Rebecca A. Dunlop, and Amelia Mack (School Martin (JASCO Res., Ltd., Victoria, BC, Canada) of Veterinary Sci., The Univ. of Queensland, Gatton, QLD 4343, Australia, [email protected]) As the Arctic seas rapidly change with increased ocean temperatures and decreased sea ice extent, traditional Arctic marine mammal distributions Acoustic surveys of marine mammals have several advantages over tra- will be altered, and non-traditionally Arctic species may shift poleward. ditional visual surveys. For an acoustic survey to be accurate, however, Arctic species typically include sperm, bowhead, humpback, right, gray, fin, there needs to be a predictable relationship between vocal behavior and den- and blue whales; odontocetes, specifically killer and beluga whales; and sev- sity. Humpback whale’s song, produced by males primarily during the eral pinnipeds species. Their acoustic presence has been documented breeding season, is potentially a good candidate for such surveys. The func- because they produce relatively low-frequency sounds that are detectable by tion of song, however, remains enigmatic and so its usefulness as a predictor many common, remotely-deployed recording platforms. Until recently, of population density is still not known, particularly when population den- however, recording constraints of power and storage limited higher sam- sity changes. We examined aspects of singing behavior during migration off pling rates and prevented the detection of many high-frequency-producing eastern Australia between 1997 and 2015 including the proportion of whales species in the Arctic seas. Such species likely include Baird’s, Cuvier’s, and that sang, the spacing between singers, and the use of song by males when Stejneger’s beaked whales, as well as Northern right whale and Pacific joining other whales. Over this period, there was a six-fold increase in the white-sided dolphins. Using one of the first long-term data sets to record rel- population but this had little effect on the proportion of whales singing, and atively high frequencies in the Bering Sea, signal types similar to those of singers spaced randomly, implying that it could be useful as a survey tool. 5a FRI. AM Baird’s and Cuvier’s beaked whales, and Pacific white-sided and Northern However, the proportion of singers that continued to sing while joining right whale dolphins have been detected. Their relative acoustic presence other whales decreased, showing some density effects on singing behavior. from the last several years will be presented, as well as the acoustic presence Altogether, while singing behavior can be used as a reasonable proxy of of other species, like Risso’s dolphin, that may be shifting northward into population size at the densities observed, behavioral strategies may start to the Arctic seas. [Work supported by ONR.] confound this relationship at higher densities. 3359 J. Acoust. Soc. Am., Vol. 140, No. 4, Pt. 2, October 2016 5th Joint Meeting ASA/ASJ 3359 9:00 a source at one or more underwater hydrophones. This estimation task can be difficult for non-impulsive sources (e.g., humpback whales) due to early 5aAB5. The correlation between the local environment and gray whale arrivals masking later ones. In linear system analysis, the impulse response behavior as tracked using a sparse hydrophone array in Monterey Bay (IR) of a system is the system output when the input is an impulse (i.e., a Regina A. Guazzo, John A. Hildebrand, Sean National Marine Sanctuary. short duration, large bandwidth signal), and expresses how a source signal M. Wiggins, Gerald L. D’Spain (Scripps Inst. of Oceanogr., Univ. of Cali- interacts with the environment to yield the output waveform (e.g., that fornia, San Diego, UCSD/SIO/0205, 9500 Gilman Dr., La Jolla, CA 92093- recorded by a hydrophone). Recordings of a relatively impulsive vocaliza- 0205, [email protected]), and David W. Weller (Southwest Fisheries Sci. tion (e.g., a walrus knock), given that they approximate the IR between the Ctr., NOAA, La Jolla, CA) walrus and hydrophone, may facilitate arrival time estimation. IR estimation Gray whales (Eschrichtius robustus) make one of the longest annual for unknown, non-impulsive calls is more challenging, particularly for time- migrations of any marine mammal. While the seasonal periodicity of the varying channels. Blind channel estimation is the process of estimating the migration and related travel corridors have been well-studied, little is known set of IRs between a single (unknown) source and multiple receivers, and about how these whales use acoustics while migrating. Acoustic array proc- can potentially help estimate direct and interface-reflected arrival times for essing is a powerful tool to localize and track vocalizing whales without dis- non-impulsive marine mammal vocalizations since the IRs can be analyzed rupting their behavior. Concurrent with the NOAA Southwest Fisheries rather than waveforms/spectra. In this paper, we use simulations to explore Science Center visual and infrared gray whale census, four hydrophone-re- the importance of ocean surface gravity waves on blind estimation of acous- corder packages with sites separated by approximately 2 km in 58 to 110 m tic IRs. water in Monterey Bay National Marine Sanctuary offshore of Granite Can- 9:45–10:00 Break yon, California, recorded from November 2014 to June 2015. An automatic call detector identified gray whale M3 calls in the dataset. Spectrogram cross-correlation was used to measure the time-difference-of-arrival of these 10:00 calls and estimate the location of the calling animal. These localizations pro- 5aAB8. Low-frequency propagation and noise in the intertidal zone. vide gray whale swimming and calling behavior and indicate changes on James S. Martin, Peter H. Rogers (School of Mech. Eng., Georgia Inst. of diel and seasonal time scales. Results from 15 high-quality tracks show call- Technol., 771 Ferst Dr., Love Bldg., Rm.