Acoustic communication is an important aspect of reproductive, foraging and social behaviours for many marine species. Northeast Pacific blue whales (Balaenoptera musculus) produce three different call types—A, B and D calls. All may be produced as singular calls, but A and B calls also occur in phrases to form songs. To evaluate the behavioural context of singular call and phrase production in blue whales, the acoustic and dive profile data from tags deployed on individuals off southern California were assessed using generalized estimating equations. Only 22% of all deployments contained sounds attributed to the tagged animal. A larger proportion of tagged animals were female (47%) than male (13%), with 40% of unknown sex. Fifty per cent of tags deployed on males contained sounds attributed to the tagged whale, while only a few (5%) deployed on females did. Most calls were produced at shallow depths (less than 30 m). Repetitive phrasing (singing) and production of singular calls were most common during shallow, non-lunging dives, with the latter also common during surface behaviour. Higher sound production rates occurred during autumn than summer and they varied with time-of-day: singular call rates were higher at dawn and dusk, while phrase production rates were highest at dusk and night.

Abstract-The data collected through ichthyoplankton monitoring surveys provide valuable insight into the spawning dynamics of multiple species. Fish eggs, more than larvae, offer a more precise evaluation of species-specific spawning characteristics; however, egg collections are greatly underused because of the limitations associated with morphology-based identifications.

To evaluate the acoustic behavior of blue whales (Balaenoptera musculus) located inshore and offshore of southern California, singular A and B calls, D calls, and AB phrases were analyzed from 12 mo of passive acoustic data collected at four locations within the Southern California Bight. The relative proportions of singular calls and phrases were used to evaluate spatial and temporal patterns in sound and song type usage, and singular call and phrase production rates were calculated to investigate spatial and temporal variability in call abundance. Blue whale sounds were recorded from spring through early winter, with the majority of all detections occurring between September and December. The proportions and production rates of singular calls and phrases varied between the inshore and offshore sites. In addition, the percentage of A units within repetitive song phrases was greater inshore than offshore, resulting from a higher proportion of AB song type inshore, in which A and B phrase units were alternating. The ABB song type, in which a single A unit was followed by multiple B units, was more common offshore. The observed differences in calling and singing behaviors may identify distinct and variable acoustic behavioral settings for blue whales off southern California.

Background: Acceptance of background noise serves as a means to predict likelihood of hearing aidsuccess. Individuals that are able to accept background noise are more likely to be successful with hearingaids.Purpose: The aim of the study was to assess the impact of sound enrichment on the acceptable noiselevel (ANL).Study Sample: Nineteen young adult participants served as listeners. Participants were randomlyassigned to the experimental or control group.Research Design: An experimental design with random assignment to experimental or control groupwas used.Data Collection and Analysis: One group used sound enrichment procedures for 2 weeks, whereas theother group served as a control group. Sound enrichment procedures required that participants add lowlevelbackground sound to any quiet environment encountered during the study. Most comfortable listeninglevel (MCL) and background noise level (BNL) were measured at three sessions, each 1 weekapart (baseline, after 1 week of treatment, and after 2 weeks of treatment).Results: Analytical statistics revealed that ANL improved for the sound enrichment group but remainedthe same for the control group. For both groups, there was no significant change in MCL across sessions.However, for the experimental group, BNL improved (increased) over the 2-week period while usingsound enrichment.Conclusions: Results of this study indicate that ANL can be improved with the use of sound enrichmentprocedures over a 2-week period. Future work should examine the use of sound enrichment proceduresfor older adults with hearing loss.