@article {57987, title = {The use of seal scarers as a protective mitigation measure can induce hearing impairment in harbour porpoises}, journal = {The Journal of the Acoustical Society of America}, volume = {146}, year = {2019}, month = {Jan-12-2019}, pages = {4288 - 4298}, abstract = {

Acoustic deterrent devices (ADDs) are used to deter seals from aquacultures but exposure of harbour porpoises (Phocoena phocoena) occurs as a side-effect. At construction sites, by contrast, ADDs are used to deter harbour porpoises from the zone in which pile driving noise can induce temporary threshold shifts (TTSs). ADDs emit such high pressure levels that there is concern that ADDs themselves may induce a TTS. A harbour porpoise in human care was exposed to an artificial ADD signal with a peak frequency of 14\ kHz. A significant TTS was found, measured by auditory evoked potentials, with an onset of 142\ dB re 1\ \μPa2s at 20\ kHz and 147\ dB re 1\ \μPa2s at 28\ kHz. The authors therefore strongly recommend to gradually increase and down regulate source levels of ADDs to the desired deterrence range. However, further research is needed to develop a reliable relationship between received levels and deterrence.

}, issn = {0001-4966}, doi = {10.1121/1.5135303}, url = {http://asa.scitation.org/doi/10.1121/1.5135303}, author = {Schaffeld, Tobias and Ruser, Andreas and Woelfing, Benno and Baltzer, Johannes and Kristensen, Jakob H. and Larsson, Josefin and Schnitzler, Joseph G. and Siebert, Ursula} } @article {57615, title = {Time of arrival difference estimation for narrow band high frequency echolocation clicks}, year = {2019}, doi = {10.1121/1.5129678}, url = {http://asa.scitation.org/doi/10.1121/1.5129678}, author = {Gillespie, Douglas and Macaulay, Jamie} } @article {53323, title = {Acoustic monitoring reveals the times and tides of harbor porpoise (Phocoena phocoena) distribution off central Oregon, U.S.A.}, journal = {Marine Mammal Science}, year = {2018}, month = {Jan-10-2020}, abstract = {

Harbor porpoises (Phocoena phocoena) are commonly observed in Oregon\’s nearshore marine environment yet knowledge of their eco- system use and behavior remains limited, generating concerns for potential impacts on this species from future coastal development. Pas- sive acoustic monitoring was used to investigate spatial and temporal variations in the presence and foraging activity of harbor porpoises off the Oregon coast from May through October 2014. Digital monitoring devices (DMONs) were deployed to record acoustic data (320 kHz sam- ple rate) in two neighboring but bathymetrically different locations off the Oregon coast: (1) a site on the 30 m isobath in close proximity (\<50 m) to a rocky reef, and (2) a site on the 60 m isobath in an open sandy environment. Data were analyzed with respect to two dynamic cyclic variables: diel and tidal phase. Porpoise presence at the rocky reef site was aligned with the ebb phase of the tidal forcing, while, har- bor porpoise presence and foraging at the offshore, sandy bottom site was associated with night-time foraging. The spatial and temporal pat- terns identified in this study suggest harbor porpoise habitat use is\ modulated by specific environmental conditions particular to each site that maximize foraging efficiency.

}, keywords = {distribution, foraging behavior, habitat use, harbor porpoise, Oregon, passive acoustics, Phocoena phocoena, temporal patterns}, doi = {10.1111/mms.12537}, url = {http://doi.wiley.com/10.1111/mms.12537}, author = {Holdman, Amanda K. and Haxel, Joseph H. and Klinck, Holger and Torres, Leigh G.} } @article {52578, title = {Silent porpoise: potential sleeping behaviour identified in wild harbour porpoises}, journal = {Animal Behaviour}, volume = {133}, year = {2017}, month = {Jan-11-2017}, pages = {211 - 222}, abstract = {

All animals sleep and it is essential for maintaining optimal brain function. However, cetaceans engage in the unusual practice of unihemispherical sleep, where only half of their brain sleeps at a time, due to their constant need for movement and breathing. Most studies of sleep in cetaceans have occurred in captivity. However, tagging devices have now developed to the point where the data collected from wild animals can be assessed against published criteria for defining sleep behaviourally. Seven acoustic and behavioural data loggers were deployed on harbour porpoises, Phocoena phocoena, in Danish waters between May 2010 and August 2011 and stayed on the animals between 53 and 72 h, recording 1884 to 2755 valid dives per animal. Parabolic dives with significantly reduced bioacoustic activity and a ste- reotyped behavioural pattern were identified as potential sleeping periods. The recordings for nearly half of the parabolic dives were found to contain no vocalization (echolocation clicks), significantly more than other dive types. Of the remaining parabolic dives, the click rate was, when normalized to their indi- vidual means, also significantly lower than detected in other dive types. Additionally, parabolic dives were shallow compared to all other dive types, and found to have a stereotypic low-energy profile. They were also found to contain fewer rolls and incorporate a lower vertical descent rate than most other dive types. If the data are representative, harbour porpoises spend a small, but meaningful amount of their diving time engaged in parabolic dives and thus potentially sleeping. All animals have a fundamental need for undisturbed sleep. These quiet periods thus need to be considered in studies of anthropogenic effects, but also those employing passive acoustic monitoring techniques, as well as in efforts to reduce incidental bycatch in fisheries, given the associated periods of reduced environmental awareness.

}, keywords = {A-tag, acoustic tags, data storage, e Phocoena, echolocation, harbour porpois, satellite telemetry, sleeping behaviour, tags}, issn = {00033472}, doi = {10.1016/j.anbehav.2017.09.015}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0003347217303020}, author = {Wright, Andrew J. and Akamatsu, Tomonari and Mouritsen, Kim N. and Sveegaard, Signe and Dietz, Rune and Teilmann, Jonas} }