Marine Mammal Monitoring Research Articles

Bayesian spatial modeling of cetacean sightings during a seismic acquisition survey

A visual monitoring of marine mammals was carried out during a seismic acquisition survey performed in waters south of Portugal with the aim of assessing the likelihood of encountering Mysticeti species in this region as well as to determine the impact of the seismic activity upon encounter.Sightings and effort data were assembled with a range of environmental variables at different lags, and a Bayesian site-occupancy modeling approach was used to develop prediction maps and evaluate how species-specific habitat conditions evolved throughout the presence or not of seismic activity.No statistical evidence of a decrease in the sighting rates of Mysticeti by comparison to source activity was found. Indeed, it was found how Mysticeti distribution during the survey period was driven solely by environmental variables.Although further research is needed, possible explanations may include anthropogenic noise habituation and zone of seismic activity coincident with a naturally low density area.

Effect of construction-related activities and vessel traffic on marine mammals

During the construction of a gas pipeline from an offshore gas field in northwest Ireland, a year-round shore-based marine mammal monitoring programme was undertaken. Using 6 yr of data, generalised estimating equations-generalised additive models (GEE-GAMs) were used to investigate if construction-related activity and vessel traffic influenced the occurrence of common dolphin, minke whale, harbour porpoise and grey seal within the area where the pipeline made landfall. Construction-related activity reduced harbour porpoise and minke whale presence, whilst an increase in vessel numbers (independent of construction-related activity) reduced common dolphin presence. All species showed some degree of annual and seasonal variation in occurrence. For common dolphins and harbour porpoises, we found similar seasonal patterns to those reported in broader Irish waters, which tentatively suggests that seasonal patterns persisted irrespective of construction-related activity or vessel traffic, indicating that any impact might have been only short-term. Multiple construction-related activities occurred simultaneously in different areas, and the inter-annual variation may, in part, be an indication of variation in species’ re sponse to particular activities, their intensity and their location. However, the precise location of the activities was not regularly recorded, limiting our ability to investigate the fine-scale spatio−temporal impact of the diverse range of construction-related activities. Improved communication and coordination between developers, regulators and scientists will help ensure that monitoring programmes are effective and efficient, to better inform our understanding of potential impacts and to mitigate effectively against them for future developments.

Non‐lethal management of carnivore predation: long‐term tests with a startle reflex‐based deterrence system on a fish farm

AbstractCarnivore depredation on human livestock is a worldwide problem with few viable solutions. Non‐lethal management tools such as acoustic devices show highly varying success and often pose a conservation risk due to noise pollution and habitat degradation. We tested the long‐term effectiveness of a deterrence system which harnesses an autonomous reflex (startle) to selectively inflict avoidance responses in a target species (phocid seals) by emitting band‐limited noise pulses with sharp onset times. Seal predation was monitored at a marine salmon farm (test site) over a full production cycle (19 month) with a multi‐transducer deterrent system deployed for the final year. Predation was also monitored for several months at two control sites and additional short‐term tests were carried out at sites which suffered higher predation rates. Generalized linear (mixed) models revealed that sound exposure caused a 91% reduction in lost fish when comparing predation levels within the test site and 97% when comparing the test site against both control sites. Similarly, sound exposure led to a 93% reduction in the number of fish lost due to seal damage at a short‐term test site. Visual monitoring of marine mammals around the long‐term test site showed that the number of seal surfacings within 100 m from the loudspeakers was only slightly lower during sound exposure. Harbour porpoise and otter distribution around the farm was not affected by sound exposure. By adjusting the frequency composition of startle stimuli, our method has the potential to provide solutions for managing human–wildlife conflicts in terrestrial and marine habitats by selectively deterring target species.

Active Acoustic Monitoring of Aquatic Life.

Active acoustic monitoring (AAM) can be used to study the behavioral response of marine life and to mitigate harm during high-danger anthropogenic activities. This has been done in fish studies for many decades, and there are now case studies in which AAM has been used for marine mammal monitoring as well. This includes monitoring where the ranges, AAM frequency of operation, and species are such that the AAM operation is completely outside the hearing range of the animals. However, it also includes AAM operations within the hearing range of marine life, although this does not necessarily that imply AAM is not a suitable tool. It is just not always possible to have a sufficient detection and tracking range and operate at a frequency outside the marine life hearing range. Likely, the best and most important application of AAM is when the anthropogenic activity to be conducted is temporary and presents a clear danger to aquatic life.

Remote passive acoustic monitoring: Listening for whales and dolphins from the safety of land

Remote passive acoustic monitoring (RPAM) is a new technology that enables the acoustic monitoring of marine mammals from an onshore location. Acoustic data are transferred in real time via satellite link from an at-sea passive acoustic monitoring (PAM) system. From anywhere in the world, an RPAM operator can detect, listen to, and track vocalizing whales and dolphins, potentially reducing the number of operators at sea.

Eight years of passive acoustic monitoring in the Alaskan Beaufort Sea: Lessons learned

Every year during open-water season in 2007–2014, up to 40 passive acoustic recorders with directional capability (DASARs) were deployed in the Beaufort Sea, as part of Shell’s Marine Mammal Monitoring and Mitigation Program. The overarching goal of these deployments was to collect information on the effects of industrial operations, such as seismic exploration and drilling activities, on the behavior of bowhead whales during their fall migration. Recorders were placed on the continental shelf at depths of <55 m, offshore of the North Slope of Alaska, between Barter Island and Harrison Bay. Over the eight-year period, more than 3.1 million bowhead calls were localized. Concurrently, various types of industrial sounds were detected and quantified, such as airgun pulses or the tones produced by machinery. Analyses were then performed by matching—for each recorder—the number of calls localized with the amount of industrial sound detected. These analyses have shown that changes in calling behavior happen at low received levels of anthropogenic sound and lead to complex changes in calling behavior, that are governed by received sound levels, but also other factors, such as distance to the industrial activity or type of industrial sound. [Work sponsored by Shell Exploration and Production Company.]

Acoustic detection of biosonar activity of deep diving odontocetes at Josephine Seamount High Seas Marine Protected Area.

The temporal occurrence of deep diving cetaceans in the Josephine Seamount High Seas Marine Protected Area (JSHSMPA), south-west Portugal, was monitored using a passive acoustic recorder. The recorder was deployed on 13 May 2010 at a depth of 814 m during the North Atlantic Treaty Organization Centre for Maritime Research and Experimentation cruise "Sirena10" and recovered on 6 June 2010. The recorder was programmed to record 40 s of data every 2 min. Acoustic data analysis, for the detection and classification of echolocation clicks, was performed using automatic detector/classification systems: M3R (Marine Mammal Monitoring on Navy Ranges), a custom matlab program, and an operator-supervised custom matlab program to assess the classification performance of the detector/classification systems. M3R CS-SVM algorithm contains templates to detect beaked whales, sperm whales, blackfish (pilot and false killer whales), and Risso's dolphins. The detections of each group of odontocetes was monitored as a function of time. Blackfish and Risso's dolphins were detected every day, while beaked whales and sperm whales were detected almost every day. The hourly distribution of detections reveals that blackfish and Risso's dolphins were more active at night, while beaked whales and sperm whales were more active during daylight hours.

Strawman outline for a standard on the use of passive acoustic towed arrays for marine mammal monitoring and mitigation

There is a perceived need from several U.S. federal agencies and departments to develop consistent standards for how passive acoustic monitoring (PAM) for marine mammals is implemented for mitigation and regulatory monitoring purposes. The use of towed array technology is already being required for geophysical exploration activities in the Atlantic Ocean and the Gulf of Mexico. However, to date no specific standards have been developed or implemented for towed arrays. Here, a strawman outline for a ANSI standard is presented (http://wp.me/P4j34t-a) to cover requirements and recommendations for the following aspects of towed array operations: initial planning (including guidelines for when PAM is not appropriate), hardware, software, and operator training requirements, real-time mitigation and monitoring procedures, and required steps for performance validation. The outline scope, at present, does not cover operational shutdown decision criteria, sound source verification, or defining the required detection range of the system. Instead of specifying details of towed array systems, the current strategy is to focus on the process of defining the required system performance for a given application, and then stepping through how the system hardware, software, and operations should be selected and validated to meet or exceed these requirements. [Work supported by BSEE.]

Chemical analysis of whale breath volatiles: a case study for non-invasive field health diagnostics of marine mammals.

We explored the feasibility of collecting exhaled breath from a moribund gray whale (Eschrichtius robustus) for potential non-invasive health monitoring of marine mammals. Biogenic volatile organic compound (VOC) profiling is a relatively new field of research, in which the chemical composition of breath is used to non-invasively assess the health and physiological processes on-going within an animal or human. In this study, two telescopic sampling poles were designed and tested with the primary aim of collecting whale breath exhalations (WBEs). Once the WBEs were successfully collected, they were immediately transferred onto a stable matrix sorbent through a custom manifold system. A total of two large volume WBEs were successfully captured and pre-concentrated onto two Tenax®-TA traps (one exhalation per trap). The samples were then returned to the laboratory where they were analyzed using solid phase micro extraction (SPME) and gas chromatography/mass spectrometry (GC/MS). A total of 70 chemicals were identified (58 positively identified) in the whale breath samples. These chemicals were also matched against a database of VOCs found in humans, and 44% of chemicals found in the whale breath are also released by healthy humans. The exhaled gray whale breath showed a rich diversity of chemicals, indicating the analysis of whale breath exhalations is a promising new field of research.

Near real-time detection, beam-forming, and telemetry of marine mammal acoustic data on a wave glider autonomous vehicle

Impacts of anthropogenic noise on marine mammals are becoming increasingly important for regulatory and research study, yet assessing and mitigating these impacts is hindered by current technology: archival underwater acoustic recorders have their data analyzed months after the activity of interest, and towed hydrophone arrays suffer from nearby ship and seismic air gun noise. This work addresses these drawbacks by developing an acoustic data acquisition and transmission system for use with a Wave Glider, to provide near real-time data for marine mammal monitoring and mitigation. The goal of the system is to be capable of months of autonomous monitoring in areas that would otherwise not be surveyed, and to transmit acoustic data within minutes of acquisition to enable rapid mitigation. Sea tests have demonstrated the proof-of-concept with the system recording four channels of acoustic data and transmitting portions of those data via satellite. Ongoing work is integrating a detection-classification algorithm on-board the Wave Glider and a beam-forming algorithm in the shore-side user interface, to provide the user with a topographic view of the Wave Glider; a sound source direction estimate; and aural and visual review of the detected sounds.

Marine Mammal Monitoring on Navy Ranges (M3R): A Toolset for Automated Detection, Localization, and Monitoring of Marine Mammals in Open Ocean Environments

AbstractNavy sonar has been associated with a number of marine mammal stranding events worldwide. As a result, determining the effects of anthropogenic noise on marine mammals is currently an active area of research. The development of methods to detect and localize the animals in their native environments is key to advancing this research and our understanding. This paper presents a collection of algorithms for automated passive acoustic detection, classification, and localization of vocalizing marine mammals in open ocean environments. The tool set known as M3R (Marine Mammal Monitoring on Navy Ranges) uses the large fields of wide-bandwidth bottom-mounted hydrophones that are part of the U.S. Navy’s undersea ranges to listen for vocalizing whales. M3R employs time-frequency analysis to passively detect whale vocalizations; it then aligns detections among neighboring hydrophones to determine the difference in times of arrival (TDOA) of each vocalization. Sets of TDOA are then used to determine 2-D or 3-D position points using hyperbolic localization techniques. An M3R system is capable of continuous, automated, real-time monitoring of over 200 wide-bandwidth hydrophones covering 2,000+ km2of open ocean. M3R is typically used in a collaborative fashion to localize animals in support of tagging exercises, visual surveys, and behavioral response experiments.

Using drifting passive echolocation loggers to study harbour porpoises in tidal-stream habitats

Moored passive acoustic detectors (e.g. C-PODs) are widely used to study harbour porpoise Phocoena phocoena distribution and relative abundance, but their use in tidal-stream habitats is complicated by the need for retrievable flow-resistant seabed fixings and the occur- rence of flow-induced noise in the resultant data. In this study, we explored the use of a new method aimed at tidal-stream habitats, which are of increasing interest for marine renewable energy generation. Porpoise detectors (C-PODs) were attached to multiple drifters and repeatedly set adrift at a tidal-stream site in western Scotland during May 2010 and August 2011. Porpoise vocalisations were successfully detected under varying tidal conditions during approximately 63 h of drifting. Harbour porpoise distribution, as determined by the drifting detectors, was similar to that found using the traditional, yet more logistically intensive, visual and acoustic boat-based sur- veys and to an extent that found by moored C-PODs. Drifting detectors also mapped tidally driven spatiotemporal variability in ambient noise levels which could influence porpoise detection. In summary, drifters equipped with passive acoustic detectors offer a new, rapid and inexpensive tool for investigating porpoise occurrence and behaviour in tidal-stream habitats, and should be considered as part of a comprehensive marine mammal monitoring approach of these energetic environments in the context of marine renewable energy development and other industries.

Long term passive acoustics monitoring reveals differences in deep diving Odontocetes foraging strategies

Beaked whales, sperm whales, pilot whales, and Risso's dolphins perform deep dives to feed on prey in the deep sea. They use echolocation to detect prey, and echolocation can be monitor as a proxy of their foraging activities. Ecological acoustic recorders were deployed to monitor in time the echolocation signals of pilot whales, Risso's dolphins, beaked whales, and sperm whales near Josephine Seamount (Portugal), in the Ligurian Sea (Italy), and along the Kona coast of the island of Hawaii. Data analysis was performed using two automatic detector/classification systems: Marine Mammal Monitoring on Navy Ranges (M3R), developed at the Naval Undersea Warfare Center Division in Newport, USA, and a custom MATLAB program. An operator-supervised custom MATLAB program was used to validate the classification performance, which was higher than 85% for each category. Results show that pilot whales and Risso's dolphins concentrate their feeding effort mainly during the night. The foraging activity of beaked and sperm whales is variable, and different patterns are observed at different locations. Prey behavior might play a central role in driving the foraging activity of deep divers, but to date, the reasons why such activity varies between species that might feed on similar food resources remains unknown.

Highlighting pros and cons of abundance estimation using passive acoustic data: monitoring fin whales (Balaenoptera physalus) off the southern Portuguese coast using seismometers

Monitoring marine mammals using passive acoustic sensors is increasingly popular. Generating abundance estimates from acoustic data would be extremely useful for marine environment stakeholders. To achieve accurate abundance estimates, there are three broad areas to consider: (1) survey design, (2) data collection and processing, and (3) data analysis. Here, we use an analysis of fin whale (Balaenoptera physalus) calls recorded on ocean bottom seismometers (OBSs) to discuss the main advantages, disadvantages and considerations of abundance estimation using acoustic data. The OBS array was deployed for one year (2007–2008) and demonstrates how an opportunistic dataset can meet survey design requirements. Ranges to detected calls (detected with a matched filter) were estimated using the seismological three-component method. Point transect sampling, an abundance estimation method, was then used to estimate average call density. Animal density or abundance could not be estimated because the appropriate average calling rate was unknown. Finally, spatiotemporal patterns of call density were modeled. This dataset has also allowed new methods development—a method that estimates abundance as a function of total energy in a species’ frequency band has been developed. In summary, abundance estimation using acoustic data is possible but challenging, and improved knowledge of vocal behavior is essential.

Comparison of remote ranging techniques for bowhead whale calls in a dispersive underwater sound channel

Locating and monitoring marine mammals near anthropogenic sound sources are important tasks with both environmental and operational consequences. This presentation describes how mode filtering (MF) or a blind-deconvolution technique (synthetic time reversal, STR) can be used to determine the range of bowhead whale calls from a single linear vertical array in a dispersive underwater sound channel. The results are based on environmental parameters at the array location, and simulations and ocean recordings of natural whale calls with a nominal bandwidth from 50 to 500 Hz. The passive listening experiments were conducted in the coastal waters near Kaktovik, Alaska, with a 12-element vertical array nominally spanning the middle 60% of the water column. It was deployed in 55-m-deep water alongside distributed arrays of Directional Autonomous Seafloor Acoustics Recorders (DASARs) arranged in triangular grids used to horizontally localize whale calls. A total of 18 naturally occurring whale calls were considered. The estimated call-to-array ranges determined from mode filtering and STR are compared with reference triangulation results from the DASARs. The vertical-array ranging results are generally within ±10% of the DASARs results with the STR results being slightly more accurate than those from mode filtering. [Sponsored by ONR and Shell.]

Errata: Aquatic Mammals, 39(1), 2013, pp. 23-53 A Review and Inventory of Fixed Autonomous Recorders for Passive Acoustic Monitoring of Marine Mammals

Errata: Aquatic Mammals, 39(1), 2013, pp. 23-53 A Review and Inventory of Fixed Autonomous Recorders for Passive Acoustic Monitoring of Marine Mammals

Nighttime foraging by deep diving echolocating odontocetes off the Hawaiian islands of Kauai and Ni'ihau as determined by passive acoustic monitors

Remote autonomous ecological acoustic recorders (EARs) were deployed in deep waters at five locations around the island of Kauai and one in waters off Ni'ihau in the main Hawaiian island chain. The EARs were moored to the bottom at depths between 400 and 800 m. The data acquisition sampling rate was 80 kHz and acoustic signals were recorded for 30 s every 5 min to conserve battery power and disk space. The acoustic data were analyzed with the M3R (Marine Mammal Monitoring on Navy Ranges) software, an energy-ratio-mapping algorithm developed at Oregon State University and custom MATLAB programs. A variety of deep diving odontocetes, including pilot whales, Risso's dolphins, sperm whales, spinner and pan-tropical spotted dolphins, and beaked whales were detected at all sites. Foraging activity typically began to increase after dusk, peaked in the middle of the night and began to decrease toward dawn. Between 70% and 84% of biosonar clicks were detected at night. At present it is not clear why some of the known deep diving species, such as sperm whales and beaked whales, concentrate their foraging efforts at night.

A Review and Inventory of Fixed Autonomous Recorders for Passive Acoustic Monitoring of Marine Mammals

Fixed autonomous acoustic recording devices (autonomous recorders [ARs]) are defined as any electronic recording system that acquires and stores acoustic data internally (i.e., without a cable or radio link to transmit data to a receiving station), is deployed semi-permanently underwater (via a mooring, buoy, or attached to the sea floor), and must be retrieved to access the data. More than 30 ARs were reviewed. They varied greatly in capabilities and costs, from small, hand-deployable units for detecting dolphin and porpoise clicks in shallow water to larger units that can be deployed in deep water and can record at high-frequency bandwidths for over a year, but must be deployed from a large vessel. The capabilities and limitations of the systems reviewed herein are discussed in terms of their effectiveness in monitoring and studying marine mammals.

Tracking beaked whales with a passive acoustic profiler float

Acoustic methods are frequently used to monitor endangered marine mammal species. Advantages of acoustic methods over visual ones include the ability to detect submerged animals, to work at night, and to work in any weather conditions. A relatively inexpensive and easy-to-use acoustic float, the QUEphone, was developed by converting a commercially available profiler float to a mobile platform, adding acoustic capability, and installing the ERMA cetacean click detection algorithm of Klinck and Mellinger [(2011). J. Acoust. Soc. Am. 129(4), 1807-1812] running on a high-power DSP. The QUEphone was tested at detecting Blainville's beaked whales at the Atlantic Undersea Test and Evaluation Center (AUTEC), a Navy acoustic test range in the Bahamas, in June 2010. Beaked whale were present at AUTEC, and the performance of the QUEphone was compared with the Navy's Marine Mammal Monitoring on Navy Ranges (M3R) system. The field tests provided data useful to evaluate the QUEphone's operational capability as a tool to detect beaked whales and report their presence in near-real time. The range tests demonstrated that the QUEphone's beaked whale detections were comparable to that of M3R's, and that the float is effective at detecting beaked whales.

Seasonal trends and spatial differences in marine mammal occurrence in Broadhaven Bay, north-west Ireland

Long-term monitoring programmes of a comparatively small area complement larger scale, but temporally limited surveys and can provide extensive datasets on seasonal occurrence and fine-scale habitat use of multiple species. A marine mammal monitoring programme, involving year-round, land-based observations, has been conducted in Broadhaven Bay candidate Special Area of Conservation, north-west Ireland, during 2002, 2005 and 2008–2011. Nine cetacean and two seal species have been recorded, with grey seal, harbour porpoise, common and bottlenose dolphins, and minke whale present throughout the year. Generalized additive models, taking into account observer effort, sighting conditions (sea state) and interannual variation, did not reveal any significant seasonal patterns in the occurrence of grey seals, bottlenose dolphins and minke whales. On the other hand, common dolphin presence in Broadhaven Bay was highest during autumn and winter. Bottlenose dolphins could be separated spatially from both common dolphins and minke whales in a classification tree by their preferential use of the shallower inshore areas of the bay (<30 m depth). However, common dolphins and minke whales, which occurred mainly in the deeper outer section of Broadhaven Bay, could not be spatially distinguished from each other, and grey seals were distributed over the entire bay. Broadhaven Bay represents an important marine mammal habitat with respect to overall species diversity and the regular occurrence of bottlenose dolphin, harbour porpoise, grey and harbour seals (all listed under Annex II of the EU Habitats Directive).