01974nas a2200181 4500008004100000022001400041245007800055210006900133260001600202300001400218490000800232520142600240100002301666700001901689700002101708700002201729856004101751 2022 eng d a0001-496600aAcoustic scaling in the European spiny lobster (Palinurus elephas)0 aAcoustic scaling in the European spiny lobster iPalinurus elepha cDec-01-2022 a3235-32440 v1523 a

Sound is an important cue for arthropods. In insects, sound features and sound-producing apparatus are tightly correlated to enhance signal emission in larger individuals. In contrast, acoustic scaling in marine arthropods is poorly described even if they possess similar sound-producing apparatus. Here, the acoustic scaling of the European spiny lobster is analyzed by recording sounds in situ at 1 m from a wide range of body sizes. The dimensions of associated sound-producing apparatus increased with body size, indicating sound features would also be influenced by spiny lobster size. Indeed, temporal sound features changed with body size, suggesting differences in calling songs could be used for spiny lobster acoustic communication. Source levels (peak–peak) ranged from 131 to 164 dB re 1 μPa for smaller and larger lobsters, respectively, which could be explained by more efficient resonating structures in larger animals. In addition, dominant frequencies were highly constrained by ambient noise levels, masking the low-frequency content of low intensity sounds from smaller spiny lobsters. Although the ecological function of spiny lobster sounds is not clear yet, these results suggest larger body sizes benefit because louder calls increase the broadcast area and potential interactions with conspecifics, as shown in the insect bioacoustic literature.

1 aJézéquel, Youenn1 aBonnel, Julien1 aEliès, Phillipe1 aChauvaud, Laurent uhttp://dx.doi.org/10.1121/10.001636301975nas a2200145 4500008004100000245009400041210006900135260001600204520147800220100002601698700002101724700001901745700001901764856004601783 2018 eng d00aLong-Term and Seasonal Changes of Large Whale Call Frequency in the Southern Indian Ocean0 aLongTerm and Seasonal Changes of Large Whale Call Frequency in t cMar-11-20203 a

In the past decades, in the context of a changing ocean submitted to an increasing human activity, a progressive decrease in the frequencies (pitch) of blue whale vocalizations has been observed worldwide. Its causes, of natural or anthropogenic nature, are still unclear. Based on 7 years of continuous acoustic recordings at widespread sites in the southern Indian Ocean, we show that this observation stands for five populations of large whales. The frequency of selected units of vocalizations of fin, Antarctic, and pygmy blue whales has steadily decreased at a rate of a few tenths of hertz per year since 2002. In addition to this interannual frequency decrease, blue whale vocalizations display seasonal frequency shifts. We show that these intra‐annual shifts correlate with seasonal changes in the ambient noise near their call frequency. This ambient noise level, in turn, shows a strong correlation with the seasonal presence of icebergs, which are one of the main sources of oceanic noise in the Southern Hemisphere. Although cause‐and‐effect relationships are difficult to ascertain, wide‐ranging changes in the acoustic environment seem to have a strong impact on the vocal behavior of large baleen whales. Seasonal frequency shifts may be due to short‐term changes in the ambient noise, and the interannual frequency decline to long‐term changes in the acoustic properties of the ocean and/or in postwhaling changes in whale abundances.

1 aLeroy, Emmanuelle, C.1 aRoyer, Jean-Yves1 aBonnel, Julien1 aSamaran, Flore uhttp://doi.wiley.com/10.1029/2018JC01435202069nas a2200217 4500008004100000022001400041245010400055210006900159260001600228300001600244490000800260520139900268100001701667700001901684700002101703700001801724700002101742700001701763700002001780856005101800 2017 eng d a0001-496600aUsing nonlinear time warping to estimate North Pacific right whale calling depths in the Bering Sea0 aUsing nonlinear time warping to estimate North Pacific right wha cJan-05-2017 a3059 - 30690 v1413 a

Calling depth distributions are estimated for two types of calls produced by critically endangered eastern North Pacific right whales (NPRWs) in the Bering Sea, using passive acoustic data collected with bottom-mounted hydrophone recorders. Nonlinear time resampling of 12 NPRW “upcalls” and 20 “gunshots” recorded in a critical NPRW habitat isolated individual normal mode arrivals from each call. The relative modal arrival times permitted range estimates between 1 and 40 km, while the relative modal amplitudes permitted call depth estimates, provided that environmental inversions were obtained from high signal-to-noise ratio calls. Gunshot sounds were generally only produced at a few meters depth, while upcall depths clustered between 10 and 25 m, consistent with previously published bioacoustic tagging results from North Atlantic right whales. A Wilcoxon rank sum test rejected the null hypothesis that the mean calling depths of the two call types were the same (p = 2.9 × 10−5); the null hypothesis was still rejected if the sample set was restricted to one call per acoustic encounter (p = 0.02). Propagation modeling demonstrates that deeper depths enhance acoustic propagation and that source depth estimates impact both NPRW upcall source level and detection range estimates.

1 aThode, Aaron1 aBonnel, Julien1 aThieury, Margaux1 aFagan, Aileen1 aVerlinden, Chris1 aWright, Dana1 aCrance, Jessica uhttp://asa.scitation.org/doi/10.1121/1.4982200