Ann Warde

Low frequency vocalizations attributed to sei whales (Balaenoptera borealis)

Low frequency (<100 Hz) downsweep vocalizations were repeatedly recorded from ocean gliders east of Cape Cod, MA in May 2005. To identify the species responsible for this call, arrays of acoustic recorders were deployed in this same area during 2006 and 2007. 70 h of collocated visual observations at the center of each array were used to compare the localized occurrence of this call to the occurrence of three baleen whale species: right, humpback, and sei whales. The low frequency call was significantly associated only with the occurrence of sei whales. On average, the call swept from 82 to 34 Hz over 1.4 s and was most often produced as a single call, although pairs and (more rarely) triplets were occasionally detected. Individual calls comprising the pairs were localized to within tens of meters of one another and were more similar to one another than to contemporaneous calls by other whales, suggesting that paired calls may be produced by the same animal. A synthetic kernel was developed to facilitate automatic detection of this call using spectrogram-correlation methods. The optimal kernel missed 14% of calls, and of all the calls that were automatically detected, 15% were false positives.

An autonomous, near‐real‐time buoy system for automatic detection of North Atlantic right whale calls.

A moored buoy system for automatic detection of endangered North Atlantic right whale (NARW) upcalls was developed to provide near‐real‐time information on the presence of whales. The marine components include the WHOI buoy platform (mooring, hydrophone, power system, surface expression, and antennae) and Cornell buoy electronics (housing, analog interface hardware, GPS, embedded computer, detection engine, and telemetry hardware). Shore‐side Cornell components include telemetry equipment, server hardware and processing software, database, and interfaces for data annotation, access, and visualization. The buoy hardware/software system is capable of capturing and ranking NARW upcall candidates as 2 s, 2000 Hz sampled audio clips. GPS location, timestamp, and other metadata associated with each audio clip are bundled together and uploaded via satellite for processing. Human analysts regularly annotate incoming data, resulting in a curated database of NARW detections. Periodic “health and status” data allow ...

SEDNA - Bioacoustic analysis toolbox

The possible effects of anthropogenic noise on the marine environment is becoming an important topic in the oceanic community. The exploration for fossil-fuel or alternative energy and the construction of facilities to support these endeavors often requires sizable construction efforts; which usually require permitting to study the impact of noise on the environment. Of particular interest is the variety of data products used to influence environmental impact reports and the processing time required to generate these data from large amounts of passive acoustic recordings. This paper outlines work being done by the Bioacoustics Research Program at Cornell University and the Lab of Ornithology, (BRP) for developing MATLAB tools in support of environmental compliance reporting. Due to the success of acoustic monitoring, understanding acoustic signatures is now becoming part of environmental impact assessment and required compliance for permitting. BRP has leveraged various existing tools and capabilities which result in integrated special purpose software tools within a MATLAB toolbox called SEDNA1. SEDNA incorporates various tools to measure acute and chronic noise levels, detect and classify marine mammal vocalizations, and compute various metrics such as receive levels, signal excess, masking and communication space. This work will summarize the high performance computing strategy used in the SEDNA Toolbox along with the capability to integrate various layers of data within a modeling framework that incorporates ambient noise, vessel and animal data. Finally, the work will demonstrate the power of this approach through animated data visualization, showing animal, vessel and ambient noise integrated over relatively large temporal and spatial scales.

Bowhead whale acoustic activity in the southeast Beaufort Sea during late summer 2008–2010

Autonomous passive acoustic recorders were deployed to record sounds of bowhead whales (Balaena mysticetus) in the southeast Beaufort Sea for periods of 30-55 days during the late summer, open-water seasons of 2008-2010. Recordings were made in three areas licensed for hydrocarbon exploration, spanning the continental slope and adjacent outer shelf, and in a shallow inner-shelf area where bowheads have been observed congregating to feed in recent decades. Bowhead sounds were counted in samples comprising 10% of each recorded hour. In mid-August and September in all 3 years, the rate of bowhead calling at outer shelf sites exceeded that at adjacent continental slope sites by one to two orders of magnitude. Higher rates of calling occurred on the slope in late July and early August than at later dates. Calling rates varied by an order of magnitude between years in the one area that was monitored in different years. The highest rates of calling occurred on the inner shelf, offshore of the northern Tuktoyaktuk Peninsula. These trends are consistent with patterns of habitat use previously reported from aerial surveys in this and nearby areas of the Beaufort Sea and with the results of satellite tagging studies.

Results and insights from operational acoustic monitoring networks.

Data from two acoustic monitoring networks operating off New England in an area frequented by whales reveal acoustic features of those habitats. These seafloor and moored systems continuously sample the acoustic environment, and resultant data provide mechanisms for mapping, quantifying, and describing the spatio‐spectral‐temporal variability of the acoustic habitat over ecologically meaningful scales. By focusing on species‐specific frequency bands used by fin, humpback, and right whales for long‐range communication, we are beginning to measure the acoustic dynamics of their primary communication channels. Results reveal the extent to which different sources of sound in the ocean, both natural and man‐made, influence the probability of whale communication. In some habitats with high rates of vessel traffic and high levels of vessel noise, the predicted area over which animals can communicate is reduced to a small proportion of what it would be under quiet conditions. The dynamics of this masking effect a...

Autonomous seafloor recorders and autodetection buoys to monitor whale activity for long‐term and near‐real‐time applications.

Biologists and engineers from Cornell have installed arrays of autonomous seafloor recorders in multiple ocean habitats. These systems are designed to continuously monitor for the occurrence of endangered whales, particularly right whales; provide critical data on whale seasonal occurrence, distribution and relative numbers; and evaluate potential noise impacts from manmade activities and commercial shipping. Recent studies have been conducted in Massachusetts Bay around commercial LNG ports, the Arctic Ocean at seismic study locations, and in New York waters extending to the shelf edge. In combination with Cornell‐developed MATLAB‐ and JAVA‐based software applications, these seafloor recorders have been utilized to evaluate seasonal whale presence, calculate levels of commercial shipping and construction noise, and locate and track the movements and behaviors of individual whales under different acoustic conditions. Cornell and ocean engineers from the Woods Hole Oceanographic Institution have installed ...

Long-term passive acoustic recordings track the changing distribution of North Atlantic right whales (Eubalaena glacialis) from 2004 to 2014

Given new distribution patterns of the endangered North Atlantic right whale (NARW; Eubalaena glacialis) population in recent years, an improved understanding of spatio-temporal movements are imperative for the conservation of this species. While so far visual data have provided most information on NARW movements, passive acoustic monitoring (PAM) was used in this study in order to better capture year-round NARW presence. This project used PAM data from 2004 to 2014 collected by 19 organizations throughout the western North Atlantic Ocean. Overall, data from 324 recorders (35,600 days) were processed and analyzed using a classification and detection system. Results highlight almost year-round habitat use of the western North Atlantic Ocean, with a decrease in detections in waters off Cape Hatteras, North Carolina in summer and fall. Data collected post 2010 showed an increased NARW presence in the mid-Atlantic region and a simultaneous decrease in the northern Gulf of Maine. In addition, NARWs were widely distributed across most regions throughout winter months. This study demonstrates that a large-scale analysis of PAM data provides significant value to understanding and tracking shifts in large whale movements over long time scales.

Results and insights from operational acoustic monitoring networks in the Chukchi Sea, Summer‐Fall 2006 and 2008.

Recordings for marine mammals were collected in the Chukchi Sea in the 2006 and 2008 summer‐fall seasons in proximity to seismic exploration activities. 2006 data were from MARUs off Cape Lisburne, Pt. Lay, Wainwright, and Pt. Barrow, AK. 2008 data were from MARUs in the Burger and Klondike areas. In 2006, belugas, but no bowheads, were rarely detected off Cape Lisburne in July–September. Bowheads, but no belugas, were detected off Wainwright, Lay, and Barrow in September–October, with bowheads very common off Barrow. Seismic airgun sounds were common on distant MARUs off Cape Lisburne, Lay, and Wainwright. There were very few seismic events detected off Barrow and those few were all close to 0‐dB SNR. In 2008, bowheads were more common at Burger than Klondike and occurred mostly during the latter part of the September–October period; belugas were not detected at Burger and only on 6 days early in the period at Klondike; walrus were more common at Burger than at Klondike. In both areas bowhead densities w...

Monitoring, measuring and describing ocean noise over ecologically viable scales with applications to impacts on large whales

Large whales communicate primarily in the low (<1000 Hz) frequency bands; the same frequency range within which anthropogenic ocean noise has been increasing over the last half century at approximately 3‐5 dB/decade. The working assumption and hypothesis hold that rising ambient noise levels negatively impact whales by interfering with communication, navigation and predator detection, and that over the long‐term such effects could reduce breeding success and population size. There is a lack of empirical data on the spatial‐temporal dynamics of ambient noise by which to assess potential impacts. One year of continuous acoustic data from an ongoing distributed array of 19 continuous seafloor recorders covering a 1000 km2 area in Massachusetts Bay, USA were analyzed for ambient noise statistics and the occurrences, locations and vocal behaviors of fin, humpback and right whales. Noise levels were greater than 120 dB rms re 1 μPa in the 10‐1000 Hz band throughout the 1000 km2 area for ⩾50% of the season when ...