Marine Mammal Observers Research Articles

Noise impact assessment on Indo-Pacific Humpback Dolphin in the habitat of the East Taiwan Strait during the first two pile driving activities of demonstration offshore wind farm

Foundation piles of the first two wind turbines were driven off the coast of Miaoli, Taiwan in 2016. However, that area is also the habitat of the critically endangered Eastern Taiwan Strait (ETS) population of Indo-Pacific humpback dolphin (Sousa chinensis). To assess potential noise effects from pile driving on the humpback dolphins, we collected underwater noise data during the construction and found that the sound pressure level (Lrms) at 750m was less than 180dB re 1μPa and the peak sound pressure (Lpk, flat) was less than 190 dB re 1μPa. We also presented recommendations of noise and marine mammal monitoring for future pile driving activities. It includes an exclusion zone of radius 750m from the piling location and the peak sound pressure (Lpk, flat) not to exceed 190~220 dB re 1μPa at 750 m distance, and an observation zone extends to 1500m radius where both marine mammal observers and passive acoustic monitoring are posted. [This work was sponsored by Ministry of Science and Technology of Taiwan (105-3113-E-002 -002 -CC2), Taiwan Bureau of Energy and Industrial technology Research Institution (05HZT56002), and U.S. Marine Mammal Commission’s Research and Conservation Grant.]

An autumn aggregation of fin (Balaenoptera physalus) and blue whales (B. musculus) in the Porcupine Seabight, southwest of Ireland

During a 16 week geophysical survey over the Porcupine Seabight (PSB) southwest of Ireland in July to October 2013, marine mammal observers logged 9382km of effort. Balaenopterid whales comprised some 60% of a total of 373 cetacean sighting events (s), with a cumulative count (n) of 392 whales. Fin whales (Balaenoptera physalus) were especially abundant (s=111, n=209) and the number of blue whales (B. musculus) seen (s=12, n=16) exceeded the total previously reported from Irish waters, but 43% of balaenopterid sightings (s=98, n=172) were not identified to species level. Data for all balaenopterid whales were pooled and generalised additive models applied to identify environmental variables that predicted whale density and to estimate abundance and the spatial distribution of density. Depth range and chlorophyll-a concentration were significant predictors of whale presence, and depth and sea floor rugosity were significant predictors of group size. There appeared to be an influx of whales in September and October and the predicted abundance peaked in October with an estimate of 138 (95% CI 121–151) whales. Analysis of the direction of movement of whales showed no significant bias in any one direction. Feeding behaviour was observed in both whale species and circumstantial evidence suggested that they were aggregating to exploit seasonally abundant northern krill (Meganyctiphanes norvegica). Chasing behaviour observed among fin whales was interpreted as evidence that this aggregation also provided opportunities for social interaction related to their reproductive cycle. The PSB may provide a link between the high latitude summer feeding habitats of krill-feeding whales and a chain of highly productive habitats in the Eastern Boundary Upwelling Ecosystems and we suggest that whales may migrate southwards in autumn along this eastern route to the northwest African upwelling zones, where productivity peaks in winter.

Use of integrated instrumentation to detect and classify targets in shallow water

The detection and classification of targets in shallow water environments (e.g., depth < 20 m) is of increasing interest, both in security applications and more general environmental studies. Here, we report the ability of a cabled integrated instrumentation system to detect and classify targets in a shallow (15 m deep), narrow (150 m wide) channel influenced by moderate tidal currents (peak currents < 2 m/s). The instrumentation system incorporates a passive acoustic array, multibeam sonar, acoustic camera, stereo-optical camera, and acoustic Doppler current profiler. The system effectiveness is benchmarked using autonomous “cooperative” targets (e.g., drifters with known position and acoustic characteristics), divers, and opportunistic observations of fish and marine mammals. By fusing data streams from multiple sensors, detection and classification rates are improved, particularly for smaller targets. Approaches to data management (data rates exceed 80 MB/s), real-time classification, and de-noising of acoustic imagery are also discussed.

First report of a dead giant squid (Architeuthis dux) from an operating seismic vessel

We report the first sighting of a dead giant squid observed from a seismic vessel operating offshore Brazil. The observation was made by Marine Mammal Observers working on the vessel. The specimen was photographed and identified as Architeuthis dux on the basis of its size and morphology. Our report adds to the limited data regarding the distribution of this species in the Southern Atlantic Ocean. Because the animal was not examined, its death cannot be conclusively linked to the seismic activity. Nevertheless, given the scarcity of observations of this species offshore Brazil, we believe this record helps to understand the species distribution as well as to highlight the disturbing lack of information on the impacts of marine sound pollution on invertebrates. This record also serves as another call for further research and for the use of precautionary principle to protect species in the deep sea.

Meals on Wheels? A Decade of Megafaunal Visual and Acoustic Observations from Offshore Oil & Gas Rigs and Platforms in the North and Irish Seas.

A decade of visual and acoustic detections of marine megafauna around offshore Oil & Gas (O&G) installations in the North and Irish Seas are presented. Marine megafauna activity was monitored visually and acoustically by Joint Nature Conservation Committee (JNCC) qualified and experienced Marine Mammal Observers (MMO) and Passive Acoustic Monitoring (PAM) Operators respectively, with real-time towed PAM in combination with industry standard software, PAMGuard. Monitoring was performed during routine O&G industrial operations for underwater noise mitigation purposes, and to ensure adherence to regulatory guidelines. Incidental sightings by off-effort MMOs and installation crew were also reported. Visual and acoustic monitoring spanned 55 non-consecutive days between 2004 and 2014. A total of 47 marine mammal sightings were recorded by MMOs on dedicated watch, and 10 incidental sightings of marine megafauna were reported over 10 years. Species included: harbour porpoise (Phocoena phocoena), Atlantic white-sided dolphin (Lagenorhynchus acutus), white beaked dolphin (Lagenorhynchus albirostris), common dolphin (Delphinus delphis), minke whale (Balaenoptera acutorostrata), common seal (Phoca vitulina), grey seal (Halichoerus grypus) and, basking shark (Cetorhinus maximus). Passive Acoustic Monitoring was conducted on two occasions in 2014; 160 PAM hours over 12 days recorded a total of 308 individual clicks identified as harbour porpoises. These appear to be the first such acoustic detections obtained from a North Sea drilling rig whilst using a typically configured hydrophone array designed for towing in combination with real-time PAMGuard software. This study provides evidence that marine megafauna are present around mobile and stationary offshore O&G installations during routine operational activities. On this basis, Environmental Impact Assessments (EIAs) for decommissioning O&G platforms should be carried-out on a case-by-case basis, and must include provisions for hitherto overlooked marine megafauna.

Assessing the Effectiveness of Ramp-Up During Sonar Operations Using Exposure Models.

Ramp-up procedures are used to mitigate the impact of sound on marine mammals. Sound exposure models combined with observations of marine mammals responding to sound can be used to assess the effectiveness of ramp-up procedures. We found that ramp-up procedures before full-level sonar operations can reduce the risk of hearing threshold shifts with marine mammals, but their effectiveness depends strongly on the responsiveness of the animals. In this paper, we investigated the effect of sonar parameters (source level, pulse-repetition time, ship speed) on sound exposure by using a simple analytical model and highlight the mechanisms that limit the effectiveness of ramp-up procedures.

Sound source localization technique using a seismic streamer and its extension for whale localization during seismic surveys.

Marine seismic surveys are under increasing scrutiny because of concern that they may disturb or otherwise harm marine mammals and impede their communications. Most of the energy from seismic surveys is low frequency, so concerns are particularly focused on baleen whales. Extensive mitigation efforts accompany seismic surveys, including visual and acoustic monitoring, but the possibility remains that not all animals in an area can be observed and located. One potential way to improve mitigation efforts is to utilize the seismic hydrophone streamer to detect and locate calling baleen whales. This study describes a method to localize low frequency sound sources with data recoded by a streamer. Beamforming is used to estimate the angle of arriving energy relative to sub-arrays of the streamer which constrains the horizontal propagation velocity to each sub-array for a given trial location. A grid search method is then used to minimize the time residual for relative arrival times along the streamer estimated by cross correlation. Results from both simulation and experiment are shown and data from the marine mammal observers and the passive acoustic monitoring conducted simultaneously with the seismic survey are used to verify the analysis.

Baleen whale localization using a dual-line towed hydrophone array during seismic reflection surveys

Three dimensional seismic reflection surveys use multiple towed hydrophone arrays for imaging the structure beneath the seafloor. Since most of the energy from seismic reflection surveys is low frequency, their impact on Baleen whales may be particularly significant. To better mitigate against this potential impact, safety radii are established based on the criteria defined by the National Marine Fisheries Service. Marine mammal observers use visual and acoustic techniques to monitor safety radii during each experiment. However, additional acoustic monitoring, in particular locating marine mammals, could demonstrate the effectiveness of the observations, and improve knowledge of animal responses to seismic experiments. In a previous study (Abadi et al., 2014), data from a single towed seismic array was used to locate Baleen whales during a seismic survey. Here, this method is expanded to a pair of towed arrays and the locations are compared with an alternative method. The experimental data utilized in this presentation are from the seismic experiment conducted by the R/V Marcus G. Langseth near Alaska in summer 2011. Results from both the simulation and experiment are shown and data from the marine mammal observers conducted simultaneously with the experiment are used to verify the analysis. [Sponsored by NSF.]

Cetacean occurrence and spatial distribution in the central Mediterranean Sea using ferries as platform of observation

While cetacean distribution and habitat is well investigated in some areas in the Mediterranean, only a few studies have been conducted so far in the central part of the Mediterranean basin. In order to fill this gap, a dedicated research program has been developed using ferries operating between Tunis and Genoa as platforms of opportunity to collect data on cetacean presence and distribution. The area was subdivided in three sub-regions: the Sardo-Tunisian channel, the eastern Sardinian margin and the international sanctuary for marine mammals Pelagos. During fall 2013, marine mammal observers surveyed 1900 nautical miles and recorded 39 encounters of 5 identified species including balaenopteridae, delphinidae, ziphiidae and physeteridae families. Bottlenose dolphin (Tursiops truncatus) and striped dolphin (Stenella coeruleoalba) were the most common species followed in decreasing occurrence by fin whale (Balaenoptera physalus), Cuvier’s beaked whale (Ziphius cavirostris) and sperm whale (Physeter macrocephalus). The distribution of bottlenose dolphin was restricted to the shallow waters of the Tunisian plateau over the continental shelf. Striped dolphins were sighted in the open sea waters and the eastern Sardinia margin. Large cetaceans as sperm whale and fin whale were mainly recorded over the canyon of Bizerte in the Sardo-Tunisian channel. Highest diversity index was reported in the Pelagos sanctuary even during autumn, confirming the area as a preferred habitat for several cetacean species. Our results also highlight the importance of the Sardo-Tunisian channel, where a relatively important diversity index has been computed, especially over the canyon of Bizerte. This study is the first to investigate cetacean diversity in pelagic central Mediterranean waters and highlights the insistent need to develop regular monitoring in this area.

An evaluation of active acoustic methods for detection of marine mammals in the Canadian Beaufort Sea

AbstractA commercially available fisheries sonar was mounted on an icebreaker and evaluated during an environmental baseline study in the Canadian Beaufort Sea, to determine the applicability of active acoustic monitoring (AAM) for marine mammal detection by comparing marine mammal observer (MMO) visual sightings and active acoustic detections. During 170 h of simultaneous MMO and AAM, 115 bowhead whales (Balaena mysticetus) and four beluga whales (Delphinapterus leucas) were visually sighted by MMOs, while 59 sonar detections of bowhead whales occurred using AAM. The fisheries sonar detected 92% of the cetaceans observed within 2,000 m. Additional observations of ringed seals (Pusa hispida) and bearded seals (Erignathus barbatus) were recorded both by MMOs and AAM. Comparative results indicate that a commercially available active acoustic system can consistently detect marine mammals within varying ranges dictated by water column properties. Shallow environments and strong pycnoclines currently present challenges to AAM.

Marine mammals observations in the Gulf of Guayaquil on the south coast of Ecuador in May–June 2013

Marine mammal (MM) observations were carried out during seismic survey of a 37 km 2 area in water depths ranging from 37-58 m in the Gulf of Guayaquil in May- June 2013. Twenty-one encounters with individual MMs or groups of MMs were recorded during 216 hours of observer effort. Bottlenose dolphins were most frequently seen, but observers also recorded the presence of striped dolphins and of humpback and killer whales and of sea lions. This short paper presents companion meteorological observations and considers the influence of weather and other environmental conditions on the frequency of the MM encounters.

Baleen whale localization using hydrophone streamers during seismic reflection surveys

Seismic reflection surveys use acoustic energy to image the structure beneath the seafloor, but concern has been raised about their potential impact on marine animals. Most of the energy from seismic surveys is low frequency, so the concern about their impact is focused on Baleen whales that communicate in the same frequency range. To better mitigate against this impact, safety radii are established based on the criteria defined by the National Marine Fisheries Service. Marine mammal observers use visual and acoustic techniques to monitor safety radii during each experiment. However, additional acoustic monitoring, in particular, locating marine mammals, could demonstrate the effectiveness of the observations, and help us understand animal responses to seismic experiments. A novel sound source localization technique using a seismic streamer has been developed. Data from seismic reflection surveys conducted with the R/V Langseth are being analyzed with this method to locate baleen whales and verify the accuracy of visual detections during experiments. The streamer is 8 km long with 636 hydrophones sampled at 500 Hz. The work focuses on time intervals when only a mitigation gun is firing because of marine mammal sightings. [Sponsored by NSF.]

Estimating the range of Baleen whale calls recorded by hydrophone streamers during seismic surveys

Like all sources of anthropogenic sound in the oceans, seismic surveys have the potential to disturb marine mammals and impede their communications. Since airgun arrays produce a considerable amount of low frequency energy, their impact on Baleen whales may be most significant. For these reasons, extensive mitigation efforts accompany seismic surveys, including visual and acoustic monitoring, but additional approaches could be useful to verify these efforts and study the behavior of whales. One approach is to utilize the hydrophone streamer to detect and locate calling Baleen whales. To develop this method, data are being analyzed from a seismic reflection survey conducted with the R/V Langseth off the coast of Washington in summer 2012. The seismic streamer is 8 km long with 636 hydrophones sampled nearly continuously at 500 Hz. The work focuses on time intervals when only a mitigation gun is firing because of marine animal sightings or turns at the ends of lines. Ranges and orientations are estimated by calculating the signal arrival angles for different groups of receivers. Data from the marine mammal observers on the R/V Langseth and other ships in the area are used to verify the analysis. [Sponsored by NSF.]

Assessment of the modern state of the Black Sea ecosystem (Republic of Abkhazia)

Marine scientific research in the southern seas of Russia is a priority goal of the Southern Scientific Center of the Russian Academy of Sciences. In the last five years, we have carried out more than 30 expedi� tions to the Black Sea [1]. Despite the fact that the ecosystem of the Black Sea is considered well studied [2–6], detailed studies in the waters of the Republic of Abkhazia were carried out up to the middle of the 1980s and were completely terminated in 1991 owing to disintegration of the USSR and a military conflict between Abkhazia and Georgia. In June 2010, multi� disciplinary ecosystem studies were carried out for the first time in 20 years in the territorial waters and exclu� sive economic zone of the Republic of Abkhazia according to the suggestion of the leaders of the Republic of Abkhazia and the Rosneft Open Society. A background assessment of the modern ecological state of the Abkhazian waters was performed. These studies were directed to the conservation and repro� duction of the natural resources and termination of the negative influence of economic activity on the envi� ronment and liquidation of its possible consequences. The field studies were carried out according to the actual legal regularities and international obligations of Russia and the Republic of Abkhazia in the sphere of ecology and safe nature management in the Black Sea basin. The expedition studies within the Gudauta licensed site included hydrobiological works (hypo� neustone, zoo�, bacterio�, phyto�, ichthyoplankton, zoo�, and phytobenthos), ichthyological investiga� tions, and observation of birds and marine mammals according to the generally accepted methods at 15 sta�

Automatic Round-the-Clock Detection of Whales for Mitigation from Underwater Noise Impacts

Loud hydroacoustic sources, such as naval mid-frequency sonars or airguns for marine geophysical prospecting, have been increasingly criticized for their possible negative effects on marine mammals and were implicated in several whale stranding events. Competent authorities now regularly request the implementation of mitigation measures, including the shut-down of acoustic sources when marine mammals are sighted within a predefined exclusion zone. Commonly, ship-based marine mammal observers (MMOs) are employed to visually monitor this zone. This approach is personnel-intensive and not applicable during night time, even though most hydroacoustic activities run day and night. This study describes and evaluates an automatic, ship-based, thermographic whale detection system that continuously scans the ship’s environs for whale blows. Its performance is independent of daylight and exhibits an almost uniform, omnidirectional detection probability within a radius of 5 km. It outperforms alerted observers in terms of number of detected blows and ship-whale encounters. Our results demonstrate that thermal imaging can be used for reliable and continuous marine mammal protection.

Community-Based Observations of Marine Mammal Occurrences in Groswater Bay, Labrador

Experienced observers from the community of Rigolet, Newfoundland and Labrador, recorded marine mammal observations at Rigolet on the coast of Labrador from July to September 2012. During this study, a total of nine species of marine mammals were documented. A daily average of 2.6 (range 1–5) marine mammal species were observed, with Harp Seals (Pagophilus groenlandicus) and Common Minke Whales (Balaenoptera acutorostrata) being the most common. The area is thought to be regionally important for Ringed Seal (Pusa hispida) whelping; however, Ringed Seals were not observed in large numbers. Beluga Whales (Delphinapterus leucas) were also reported anecdotally, but were less common than the other species, with the possible exception of the Harbour Porpoise (Phocoena phocoena). Labrador is experiencing significant industrial growth related to hydroelectric development and offshore oil and gas exploration. These data should aid environmental assessment and environmental effects monitoring and assist researchers in understanding regional marine mammal ecology, including species diversity, seasonal occurrence, and relative abundance.

Bryde's whale calls recorded in the Gulf of Mexico

Bryde's whale calls recorded in the Gulf of Mexico

Sustainable Tourism: Whale Watching Footprint in the Bahía de Banderas, México

ABSTRACT Cornejo-Ortega, J.L.; Chavez-Dagostino, R.M., and Massam, B.H., 2013. Sustainable tourism: whale watching footprint in the Bahia de Banderas, Mexico. The discussion about nonsustainable ecological systems is in vogue. The debate has led to the biophysical analysis of “human-nature” relationships. This analysis is an important way to determine human impacts on the Earth, based on the colonization of nature and social activities that consider matter and energy flows through appropriation, transformation, distribution, consumption, and excretion. Tourism has appropriated and characterized various types of ecosystems that represent the use of a finite set of spatially distributed resources. The observation of marine mammals, such as whales, in natural protected areas attracts many tourists each year, and this activity indirectly generates carbon dioxide that is released into the atmosphere. This carbon emission, which is accompanied by the increased scale of tourism, may hamper global conservation go...

Cetacean distribution and abundance in relation to oceanographic domains on the eastern Bering Sea shelf, June and July of 2002, 2008, and 2010

As part of the Bering Sea Project, cetacean surveys were conducted to describe distribution and estimate abundance on the eastern Bering Sea shelf. Three marine mammal observers conducted visual surveys along transect lines sampled during the Alaska Fisheries Science Center walleye pollock assessment survey in June and July of 2008 and 2010. Distribution and abundance in 2008 and 2010 (cold years) are compared with results from a similar survey conducted in 2002 (a warm year), as the only three years that the entire survey area was sampled; patterns largely match those previously observed. Abundance estimates for comparable areas in 2002, 2008 and 2010 were as follows: humpback whales (Megaptera novaeangliae): 231 (CV=0.63), 436 (CV=0.45), and 675 (CV=0.80); fin whales (Balaenoptera physalus): 419 (CV=0.33), 1368 (CV=0.34), and 1061 (CV=0.38); minke whales (Balaenoptera acutorostrata): 389 (CV=0.52), 517 (CV=0.69), and 2020 (CV=0.73); Dall's porpoise (Phocoenoides dalli): 35,303 (CV=0.53), 14,543 (CV=0.32), and 11,143 (CV=0.32); and harbor porpoise (Phocoena phocoena): 1971 (CV=0.46), 4056 (CV=0.40), and 833 (CV=0.66). It should be noted that these abundance estimates are not corrected for biases due to perception, availability, or responsive movement. Estimates for humpback, fin and minke whales increased from 2002 to 2010, while those for harbor and Dall's porpoise decreased; trends were significant for fin whales. It is likely that changes in estimated abundance are due at least in part to shifts in distribution and not just changes in overall population size. Annual abundance estimates were examined by oceanographic domain. Humpback whales were consistently concentrated in coastal waters north of Unimak Pass. Fin whales were broadly distributed in the outer domain and slope in 2008 and 2010, but sightings were sparse in 2002. Minke whales were distributed throughout the study area in 2002 and 2008, but in 2010 they were concentrated in the outer domain and slope. In 2002, Dall's porpoise were sighted on the western edge of the middle domain and in the outer domain and slope, but shifted west out of the middle domain in 2008 and 2010. In 2002 and 2008, harbor porpoise were consistently found in the middle domain with scattered sightings in the outer domain and slope. In 2010, there was a multi-species aggregation between Navarin and Pervenets canyons.

Environmentally neutral complex broadband biomimetic waveforms for active sonar

There is an expanding requirement to reduce the impact of man-made sound, including active sonar transmissions, on marine mammals in the defence, offshore and other sectors. This is driven partly by increased public interest in these animals, but mainly by legislation such as the US Marine Mammal Protection Act, and similar regulatory and licensing requirements throughout the world. Typically, such requirements are met using monitoring by Marine Mammal Observers or Passive Acoustic Monitoring. Having detected animals within a specified range, some form of mitigating action such as shutting down the sound source is then necessary. However, in general it is difficult to ensure the absence of marine mammals before transmitting, so it is desirable to look for forms of sonar waveform that are potentially less harmful to marine life. One way this might be achieved is to use signals derived from natural sounds such as the vocalisations of the animals themselves. It might be expected that such sounds would appear more familiar, thus reducing possible abnormal behavioural impacts. This paper reviews the use of such waveforms and presents a preliminary estimate of their performance in practical sonar systems, along with an assessment of the potential impacts on marine life.