Male Humpback Whale Chorusing in Hawai‘i and Its Relationship With Whale Abundance and Density

Passive acoustic monitoring (PAM) with autonomous bottom-moored recorders is widely used to study cetacean occurrence, distribution and behaviors, as it is less affected by factors that limit other observation methods (e.g., vessel, land and aerial-based surveys) such as inclement weather, sighting conditions, or remoteness of study sites. During the winter months in Hawai‘i, humpback whale male song chorusing becomes the predominant contributor to the local soundscape and previous studies showed a strong seasonal pattern, suggesting a correlation with relative whale abundance. However, the relationship between chorusing levels and abundance, including non-singing whales, is still poorly understood. To investigate how accurately acoustic monitoring of singing humpback whales tracks their abundance, and therefore is a viable tool for studying whale ecology and population trends, we collected long-term PAM data from three bottom-moored Ecological Acoustic Recorders off west Maui, Hawaii during the winter and spring months of 2016–2021. We calculated daily medians of root-mean-square sound pressure levels (RMS SPL) of the low frequency acoustic energy (0–1.5 kHz) as a measure of cumulative chorusing intensity. In addition, between December and April we conducted a total of 26 vessel-based line-transect surveys during the 2018/19 through 2020/21 seasons and weekly visual surveys (n = 74) from a land-based station between 2016 and 2020, in which the location of sighted whale pods was determined with a theodolite. Combining the visual and acoustic data, we found a strong positive second-order polynomial correlation between SPLs and abundance (land: 0.72 ≤ R2 ≤ 0.75, vessel: 0.81 ≤ R2 ≤ 0.85 for three different PAM locations; Generalized Linear Model: pland ≪ 0.001, pvessel ≪ 0.001) that was independent from recording location (pland = 0.23, pvessel = 0.9880). Our findings demonstrate that PAM is a relatively low-cost, robust complement and alternative for studying and monitoring humpback whales in their breeding grounds that is able to capture small-scale fluctuations during the season and can inform managers about population trends in a timely manner. It also has the potential to be adapted for use in other regions that have previously presented challenges due to their remoteness or other limitations for conducting traditional surveys.

Integrated approach to reducing drinking water losses in the distribution networks in the city of Sebastopol

Природный дефицит водных ресурсов в сочетании с высокой степенью износа систем водоснабжения обусловливает напряженную ситуацию с обеспечением питьевой водой в Крыму. За последние несколько лет для решения проблемы на региональном и федеральном уровне были разработаны и реализуются программы модернизации водного хозяйства полуострова. Одной из ключевых задач этих программ является снижение потерь воды, которые в настоящее время достигают 40–60%. Описан комплекс мероприятий, направленных на снижение потерь воды в г. Севастополе. Комплекс мер, разработанный в соответствии с международным опытом и российскими рекомендациями, учитывает существующее состояние системы водоснабжения Крыма. Мероприятия включают в себя создание современного комплекса управления сетями, зонирование водопроводной сети, регулирование давления, мониторинг и устранение утечек. По результатам анализа производственных показателей определено, что первоочередным мероприятием для Севастополя является внедрение современной системы акустического мониторинга на распределительных сетях, которая позволит эффективно обнаруживать скрытые утечки и сэкономить городу тысячи кубометров дефицитной питьевой воды. Описаны результаты пилотного проекта по обследованию 5 км водопроводных сетей системой акустического мониторинга. The natural scarcity of water resources coupled with a high degree of deterioration of water supply systems result in a tense situation with the drinking water supply in Crimea. Over the past few years, a number of programs of upgrading the peninsula's water industry have been developed and are being implemented in order to solve the problem at the regional and federal levels. One of the key objectives of these programs is to reduce water losses that currently reach 40–60%. A set of measures aimed at reducing water losses in Sebastopol is described. The set of measures developed in accordance with the international experience and Russian recommendations takes into account the current condition of the Crimean water supply system. The activities include designing an advanced network management complex, zoning of the water supply network, pressure regulation, monitoring and elimination of leaks. Based on the results of the analysis of the performance indicators, it was determined that the priority measure for Sebastopol was the introduction of an advanced acoustic monitoring system in the water distribution networks that would provide for detecting effectively latent leaks and saving the city thousands of cubic meters of scarce drinking water. The results of a pilot project on the inspection of 5 km of the water supply networks using the acoustic monitoring system are described.

Marine soundscape and fish biophony of a Mediterranean marine protected area

Background Marine soundscape is the aggregation of sound sources known as geophony, biophony, and anthrophony. The soundscape analysis, in terms of collection and analysis of acoustic signals, has been proposed as a tool to evaluate the specific features of ecological assemblages and to estimate their acoustic variability over space and time. This study aimed to characterise the Capo Caccia-Isola Piana Marine Protected Area (Italy, Western Mediterranean Sea) soundscape over short temporal (few days) and spatial scales (few km) and to quantify the main anthropogenic and biological components, with a focus on fish biophonies. Methods Within the MPA, three sites were chosen each in a different protection zone (A for the integral protection, B as the partial protection, and C as the general protection). In each site, two underwater autonomous acoustic recorders were deployed in July 2020 at a depth of about 10 m on rocky bottoms. To characterise the contribution of both biophonies and anthrophonies, sea ambient noise (SAN) levels were measured as sound pressure level (SPL dB re: 1 μ Pa-rms) at eight 1/3 octave bands, centred from 125 Hz to 16 kHz, and biological and anthropogenic sounds were noted. Fish sounds were classified and counted following a catalogue of known fish sounds from the Mediterranean Sea based on the acoustic characteristic of sound types. A contemporary fish visual census had been carried out at the test sites. Results SPL were different by site, time (day vs. night), and hour. SPLs bands centred at 125, 250, and 500 Hz were significantly higher in the daytime, due to the high number of boats per minute whose noise dominated the soundscapes. The loudest man-made noise was found in the A zone, followed by the B and the C zone, confirming that MPA current regulations do not provide protection from acoustic pollution. The dominant biological components of the MPA soundscape were the impulsive sounds generated by some invertebrates, snapping shrimps and fish. The vast majority of fish sounds were recorded at the MPA site characterized by the highest sound richness, abundance, and Shannon-Wiener index, coherently with the results of a fish visual census. Moreover, the acoustic monitoring detected a sound associated with a cryptic species (Ophidion spp.) never reported in the study area before, further demonstrating the usefulness of passive acoustic monitoring as a complementary technique to species census. This study provides baseline data to detect future changes of the marine soundscapes and some suggestions to reduce the impact of noise on marine biodiversity.

Real-Time Continuous Acoustic Monitoring of Marine Mammals in the Mediterranean Sea

The passive acoustic monitoring of cetaceans is a research method that can provide unique information on the animal’s behaviour since the animals can be studied at great depths and at a long-range without interference. Nevertheless, the real-time data collection, transfer, and analysis using these techniques are difficult to implement and maintain. In this paper, a review of several experiments that have used this approach will be provided. The first class of detectors consists of hydrophone systems housed under buoys on the sea surface with wireless data transmission, while the second type comprises several acoustic detector networks integrated within submarine neutrino telescopes cabled to the shore.

Fault detection of contactor using acoustic monitoring

Recently, condition monitoring methods using the sound of the machine have attracted attention. Since approaching high voltage equipment increases the risk of electrocuting, non-contact data acquisition is desirable. Most of the research targets of acoustic monitoring are rotating machines and it is not clear whether it is effective for machines that switch between two states, such as contactors and circuit breakers. In this work, several investigations have been carried out on the acoustic condition monitoring of contactor. The Mel-frequency cepstrum coefficients (MFCCs) were obtained from the sound data of the contactors under normal and simulated fault conditions. Support Vector Machine (SVM) was trained with MFCCs and found that it could detect and diagnose contactor faults with high accuracy.

Beluga whale (Delphinapterus leucas) acoustic foraging behavior and applications for long term monitoring

Cook Inlet, Alaska, is home to an endangered and declining population of 279 belugas (Delphinapterus leucas). Recovery efforts highlight a paucity of basic ecological knowledge, impeding the correct assessment of threats and the development of recovery actions. In particular, information on diet and foraging habitat is very limited for this population. Passive acoustic monitoring has proven to be an efficient approach to monitor beluga distribution and seasonal occurrence. Identifying acoustic foraging behavior could help address the current gap in information on diet and foraging habitat. To address this conservation challenge, eight belugas from a comparative, healthy population in Bristol Bay, Alaska, were instrumented with a multi-sensor tag (DTAG), a satellite tag, and a stomach temperature transmitter in August 2014 and May 2016. DTAG deployments provided 129.6 hours of data including foraging and social behavioral states. A total of 68 echolocation click trains ending in terminal buzzes were identified during successful prey chasing and capture, as well as during social interactions. Of these, 37 click trains were successfully processed to measure inter-click intervals (ICI) and ICI trend in their buzzing section. Terminal buzzes with short ICI (minimum ICI <8.98 ms) and consistently decreasing ICI trend (ICI increment range <1.49 ms) were exclusively associated with feeding behavior. This dual metric was applied to acoustic data from one acoustic mooring within the Cook Inlet beluga critical habitat as an example of the application of detecting feeding in long-term passive acoustic monitoring data. This approach allowed description of the relationship between beluga presence, feeding occurrence, and the timing of spawning runs by different species of anadromous fish. Results reflected a clear preference for the Susitna River delta during eulachon (Thaleichthys pacificus), Chinook (Oncorhynchus tshawytscha), pink (Oncorhynchus gorbuscha), and coho (Oncorhynchus kisutch) salmon spawning run periods, with increased feeding occurrence at the peak of the Chinook and pink salmon runs.