Baumgartner Mark F.

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Mark F.

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  • Article
    Striking the right balance in right whale conservation
    (NRC Research Press, 2009-08-14) Schick, Robert S. ; Halpin, Patrick N. ; Read, Andrew J. ; Slay, Christopher K. ; Kraus, Scott D. ; Mate, Bruce R. ; Baumgartner, Mark F. ; Roberts, Jason J. ; Best, Benjamin D. ; Good, Caroline P. ; Loarie, Scott R. ; Clark, James S.
    Despite many years of study and protection, the North Atlantic right whale (Eubalaena glacialis) remains on the brink of extinction. There is a crucial gap in our understanding of their habitat use in the migratory corridor along the eastern seaboard of the United States. Here, we characterize habitat suitability in migrating right whales in relation to depth, distance to shore, and the recently enacted ship speed regulations near major ports. We find that the range of suitable habitat exceeds previous estimates and that, as compared with the enacted 20 nautical mile buffer, the originally proposed 30 nautical mile buffer would protect more habitat for this critically endangered species.
  • Preprint
    Evidence of a North Atlantic right whale calf (Eubalaena glacialis) born in northeastern U.S. waters
    ( 2008-08-30) Patrician, Melissa R. ; Biedron, Ingrid S. ; Esch, H. Carter ; Wenzel, Frederick W. ; Cooper, Lindsay A. ; Hamilton, Philip K. ; Glass, Allison H. ; Baumgartner, Mark F.
    The general temporal and geographical patterns of North Atlantic right whale (Eubalaena glacialis) calving events have been clarified during the last quarter century of research (Kraus and Rolland 2007). Right whales give birth to a single calf every three to five years after a twelve- to thirteen-month gestation period (Best 1994; Kraus and Hatch 2001). Most calves are born between December and March in the coastal waters of the southeastern U.S., the only known calving ground for this species (Kraus et al. 2007; Winn et al. 1986). Although historical whaling records suggest that there were once two winter calving grounds, one off the southeastern U.S. and the other off northwestern Africa, it appears that only the former is still used today (Notarbartolo di Sciara et al. 1998; Reeves and Mitchell 1986; 1988). In the late winter, right whales leave the calving grounds and migrate to their foraging grounds off the northeastern U.S. and Canadian Maritimes. North Atlantic right whales can be found in Cape Cod and Massachusetts Bays throughout the late winter and early spring (Hamilton and Mayo 1990; Mayo and Marx 1990; Schevill et al. 1986), in the Great South Channel during mid-spring to early summer (Kenney et al. 1995), and in the Bay of Fundy (Kraus et al. 1982) and on the Scotian Shelf (Mitchell et al. 1986; Stone et al. 1988) during the summer and fall. Some individuals (mostly pregnant females and juveniles) return to the calving grounds off the southeastern U.S. in December and January, but the location of the rest of the population during those months is currently unknown (although recent evidence suggests that right whales are present in the Gulf of Maine and on the Scotian Shelf throughout the winter (Mellinger et al. 2007; T. Cole pers comm. ; S. Van Parijs pers comm. ).
  • Article
    Long distance passive localization of vocalizing sei whales using an acoustic normal mode approach
    (Acoustical Society of America, 2012-02) Newhall, Arthur E. ; Lin, Ying-Tsong ; Lynch, James F. ; Baumgartner, Mark F. ; Gawarkiewicz, Glen G.
    During a 2 day period in mid-September 2006, more than 200, unconfirmed but identifiable, sei whale (Balaenoptera borealis) calls were collected as incidental data during a multidisciplinary oceanography and acoustics experiment on the shelf off New Jersey. Using a combined vertical and horizontal acoustic receiving array, sei whale movements were tracked over long distances (up to tens of kilometers) using a normal mode back propagation technique. This approach uses low-frequency, broadband passive sei whale call receptions from a single-station, two-dimensional hydrophone array to perform long distance localization and tracking by exploiting the dispersive nature of propagating normal modes in a shallow water environment. The back propagation approach is examined for accuracy and application to tracking the sei whale vocalizations identified in the vertical and horizontal array signals. This passive whale tracking, combined with the intensive oceanography measurements performed during the experiment, was also used to examine sei whale movements in relation to oceanographic features observed in this region.
  • Article
    Long-term passive acoustic recordings track the changing distribution of North Atlantic right whales (Eubalaena glacialis) from 2004 to 2014
    (Nature Publishing Group, 2017-10-18) Davis, Genevieve E. ; Baumgartner, Mark F. ; Bonnell, Julianne M. ; Bell, Joel ; Berchok, Catherine L. ; Bort Thornton, Jacqueline ; Brault, Solange ; Buchanan, Gary ; Charif, Russell A. ; Cholewiak, Danielle ; Clark, Christopher W. ; Corkeron, Peter ; Delarue, Julien ; Dudzinski, Kathleen ; Hatch, Leila ; Hildebrand, John ; Hodge, Lynne ; Klinck, Holger ; Kraus, Scott D. ; Martin, Bruce ; Mellinger, David K. ; Moors-Murphy, Hilary ; Nieukirk, Sharon ; Nowacek, Douglas P. ; Parks, Susan E. ; Read, Andrew J. ; Rice, Aaron N. ; Risch, Denise ; Širović, Ana ; Soldevilla, Melissa ; Stafford, Kathleen M. ; Stanistreet, Joy ; Summers, Erin ; Todd, Sean ; Warde, Ann M. ; Van Parijs, Sofie M.
    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.
  • Technical Report
    Acoustic and oceanographic observations collected during the Nomans Island experiment in Spring 2017
    (Woods Hole Oceanographic Institution, 2020-07) Johnson, Hansen D. ; Newhall, Arthur E. ; Lin, Ying-Tsong ; Baumgartner, Mark F.
    The Woods Hole Oceanographic Institution (WHOI) has developed a digital acoustic monitoring (DMON) instrument and low-frequency detection and classification system (LFDCS) to detect and classify baleen whales in near real-time from autonomous platforms. This document provides a detailed description of the data, sensors, and research activities pertaining to the Nomans Island experiment, which was designed to evaluate the range-dependent accuracy of the DMON/LFDCS on mobile and fixed platforms. The experiment took place over a 4-week period (28 Feb to 31 Mar) in the spring of 2017 at a shallow (30m) site approximately 15 km Southwest of Martha’s Vineyard, USA. A DMON/LFDCS-equipped Slocum glider was deployed alongside an extant DMON/LFDCS moored buoy to provide the means to compare system performance between platforms. Vertical and horizontal hydrophone line arrays were deployed in the same area to facilitate call localization. A short transmission loss trial was conducted shortly after the array deployments. The Slocum glider and several sensors mounted to the arrays provided environmental data to characterize variability in water column structure and sound speed during the study period.
  • Article
    Slocum gliders provide accurate near real-time estimates of baleen whale presence from human-reviewed passive acoustic detection information
    (Frontiers Media, 2020-02-25) Baumgartner, Mark F. ; Bonnell, Julianne M. ; Corkeron, Peter ; Van Parijs, Sofie M. ; Hotchkin, Cara ; Hodges, Benjamin A. ; Bort Thornton, Jacqueline ; Mensi, Bryan L. ; Bruner, Scott M.
    Mitigating the effects of human activities on marine mammals often depends on monitoring animal occurrence over long time scales, large spatial scales, and in real time. Passive acoustics, particularly from autonomous vehicles, is a promising approach to meeting this need. We have previously developed the capability to record, detect, classify, and transmit to shore information about the tonal sounds of baleen whales in near real time from long-endurance ocean gliders. We have recently developed a protocol by which a human analyst reviews this information to determine the presence of marine mammals, and the results of this review are automatically posted to a publicly accessible website, sent directly to interested parties via email or text, and made available to stakeholders via a number of public and private digital applications. We evaluated the performance of this system during two 3.75-month Slocum glider deployments in the southwestern Gulf of Maine during the spring seasons of 2015 and 2016. Near real-time detections of humpback, fin, sei, and North Atlantic right whales were compared to detections of these species from simultaneously recorded audio. Data from another 2016 glider deployment in the same area were also used to compare results between three different analysts to determine repeatability of results both among and within analysts. False detection (occurrence) rates on daily time scales were 0% for all species. Daily missed detection rates ranged from 17 to 24%. Agreement between two trained novice analysts and an experienced analyst was greater than 95% for fin, sei, and right whales, while agreement was 83–89% for humpback whales owing to the more subjective process for detecting this species. Our results indicate that the presence of baleen whales can be accurately determined using information about tonal sounds transmitted in near real-time from Slocum gliders. The system is being used operationally to monitor baleen whales in United States, Canadian, and Chilean waters, and has been particularly useful for monitoring the critically endangered North Atlantic right whale throughout the northwestern Atlantic Ocean.
  • Article
    Bowhead whales use two foraging strategies in response to fine-scale differences in zooplankton vertical distribution
    (Nature Research, 2020-11-20) Fortune, Sarah M. E. ; Ferguson, Steven H. ; Trites, Andrew W. ; Hudson, Justine M. ; Baumgartner, Mark F.
    As zooplanktivorous predators, bowhead whales (Balaena mysticetus) must routinely locate patches of prey that are energy-rich enough to meet their metabolic needs. However, little is known about how the quality and quantity of prey might influence their feeding behaviours. We addressed this question using a new approach that included: (1) multi-scale biologging and unmanned aerial system observations of bowhead whales in Cumberland Sound, Nunavut (Canada), and (2) an optical plankton counter (OPC) and net collections to identify and enumerate copepod prey species through the water column. The OPC data revealed two prey layers comprised almost exclusively of lipid-rich calanoid copepods. The deep layer contained fewer, but larger, particles (10% greater overall biomass) than the shallow prey layer. Dive data indicated that the whales conducted long deep Square-shaped dives (80% of dives; averaging depth of 260.4 m) and short shallow Square-shaped dives (16%; averaging depth of 22.5 m) to feed. The whales tended to dive proportionally more to the greater biomass of zooplankton that occurred at depth. Combining behavioural recordings with prey sampling showed a more complex feeding ecology than previously understood, and provides a means to evaluate the energetic balance of individuals under current environmental conditions.
  • Article
    Summer and fall habitat of North Atlantic right whales (Eubalaena glacialis) inferred from satellite telemetry
    (National Research Council Canada, 2005-04-12) Baumgartner, Mark F. ; Mate, Bruce R.
    Satellite-monitored radio tags were attached to North Atlantic right whales (Eubalaena glacialis) in Grand Manan Basin of the lower Bay of Fundy during the summer and early fall seasons of 1989–1991 and 2000. Monte Carlo tests were used to examine the distribution of the tagged whales in space and time and with respect to a variety of environmental variables to characterize right whale habitat on their northern feeding grounds. These environmental variables included depth, depth gradient, climatological surface and bottom hydrographic properties, and remotely sensed surface temperature, chlorophyll concentration, and their respective horizontal gradients. Site fidelity in the Bay of Fundy was very low during 1989–1991 and high during 2000. When the tagged animals left the Bay, they did not frequently visit the deep basins of the Gulf of Maine and Scotian Shelf, where abundances of their primary copepod prey, Calanus finmarchicus, are thought to be high. Instead, right whales visited areas characterized by low bottom water temperatures, high surface salinity, and high surface stratification. No evidence was found that the tagged right whales associated with oceanic fronts or regions with high standing stocks of phytoplankton.
  • Article
    A generalized baleen whale call detection and classification system
    (Acoustical Society of America, 2011-05) Baumgartner, Mark F. ; Mussoline, Sarah E.
    Passive acoustic monitoring allows the assessment of marine mammal occurrence and distribution at greater temporal and spatial scales than is now possible with traditional visual surveys. However, the large volume of acoustic data and the lengthy and laborious task of manually analyzing these data have hindered broad application of this technique. To overcome these limitations, a generalized automated detection and classification system (DCS) was developed to efficiently and accurately identify low-frequency baleen whale calls. The DCS (1) accounts for persistent narrowband and transient broadband noise, (2) characterizes temporal variation of dominant call frequencies via pitch-tracking, and (3) classifies calls based on attributes of the resulting pitch tracks using quadratic discriminant function analysis (QDFA). Automated detections of sei whale (Balaenoptera borealis) downsweep calls and North Atlantic right whale (Eubalaena glacialis) upcalls were evaluated using recordings collected in the southwestern Gulf of Maine during the spring seasons of 2006 and 2007. The accuracy of the DCS was similar to that of a human analyst: variability in differences between the DCS and an analyst was similar to that between independent analysts, and temporal variability in call rates was similar among the DCS and several analysts.
  • Article
    Acoustic detection range of right whale upcalls identified in near-real time from a moored buoy and a Slocum glider
    (Acoustical Society of America, 2022-04-13) Johnson, Hansen D. ; Taggart, Christopher T. ; Newhall, Arthur E. ; Lin, Ying-Tsong ; Baumgartner, Mark F.
    The goal of this study was to characterize the detection range of a near real-time baleen whale detection system, the digital acoustic monitoring instrument/low-frequency detection and classification system (DMON/LFDCS), equipped on a Slocum glider and a moored buoy. As a reference, a hydrophone array was deployed alongside the glider and buoy at a shallow-water site southwest of Martha's Vineyard (Massachusetts, USA) over a four-week period in spring 2017. A call-by-call comparison between North Atlantic right whale upcalls localized with the array (n = 541) and those detected by the glider or buoy was used to estimate the detection function for each DMON/LFDCS platform. The probability of detection was influenced by range, ambient noise level, platform depth, detection process, review protocol, and calling rate. The conservative analysis of near real-time pitch tracks suggested that, under typical conditions, a 0.33 probability of detection of a single call occurred at 6.2 km for the buoy and 8.6–13.4 km for the glider (depending on glider depth), while a 0.10 probability of detection of a single call occurred at 14.4 m for the buoy and 22.6–27.5 km for the glider. Probability of detection is predicted to increase substantially at all ranges if more than one call is available for detection.
  • Article
    Real-time reporting of baleen whale passive acoustic detections from ocean gliders
    (Acoustical Society of America, 2013-08) Baumgartner, Mark F. ; Fratantoni, David M. ; Hurst, Thomas P. ; Brown, Moira W. ; Cole, Timothy V. N. ; Van Parijs, Sofie M. ; Johnson, Mark P.
    In the past decade, much progress has been made in real-time passive acoustic monitoring of marine mammal occurrence and distribution from autonomous platforms (e.g., gliders, floats, buoys), but current systems focus primarily on a single call type produced by a single species, often from a single location. A hardware and software system was developed to detect, classify, and report 14 call types produced by 4 species of baleen whales in real time from ocean gliders. During a 3-week deployment in the central Gulf of Maine in late November and early December 2012, two gliders reported over 25 000 acoustic detections attributed to fin, humpback, sei, and right whales. The overall false detection rate for individual calls was 14%, and for right, humpback, and fin whales, false predictions of occurrence during 15-min reporting periods were 5% or less. Transmitted pitch tracks—compact representations of sounds—allowed unambiguous identification of both humpback and fin whale song. Of the ten cases when whales were sighted during aerial or shipboard surveys and a glider was within 20 km of the sighting location, nine were accompanied by real-time acoustic detections of the same species by the glider within ±12 h of the sighting time.
  • Article
    Near real-time detection of low-frequency baleen whale calls from an autonomous surface vehicle: implementation, evaluation, and remaining challenges
    (Acoustical Society of America, 2021-05-04) Baumgartner, Mark F. ; Ball, Keenan R. ; Partan, James W. ; Pelletier, Léo‐Paul ; Bonnell, Julianne M. ; Hotchkin, Cara ; Corkeron, Peter ; Van Parijs, Sofie M.
    Mitigation of threats posed to marine mammals by human activities can be greatly improved with a better understanding of animal occurrence in real time. Recent advancements have enabled low-power passive acoustic systems to be integrated into long-endurance autonomous platforms for persistent near real-time monitoring of marine mammals via the sounds they produce. Here, the integration of a passive acoustic instrument capable of real-time detection and classification of low-frequency (LF) tonal sounds with a Liquid Robotics wave glider is reported. The goal of the integration was to enable monitoring of LF calls produced by baleen whales over periods of several months. Mechanical noises produced by the platform were significantly reduced by lubricating moving parts with polytetrafluoroethylene, incorporating rubber and springs to decelerate moving parts and shock mounting hydrophones. Flow noise was reduced with the development of a 21-element hydrophone array. Surface noise produced by breaking waves was not mitigated despite experimentation with baffles. Compared to a well-characterized moored passive acoustic monitoring buoy, the system greatly underestimated the occurrence of sei, fin, and North Atlantic right whales during a 37-d deployment, and therefore is not suitable in its current configuration for use in scientific or management applications for these species at this time.
  • Preprint
    Spatial and temporal distribution of cetaceans in the mid-Atlantic waters around the Azores
    ( 2013-02) Silva, Monica A. ; Prieto, Rui ; Cascao, Irma ; Seabra, Maria I. ; Machete, Miguel ; Baumgartner, Mark F. ; Santos, Ricardo S.
    Cetaceans living in offshore waters are under increasing pressure from anthropogenic activities. Yet, due to the lack of survey effort, relatively little is known about the demography or ecology of these populations. Spatial and temporal distribution of cetaceans in mid-Atlantic waters were investigated using a long term dataset collected from boat surveys and land-based observations around the Azores. From 1999 to 2009, 7307 cetacean schools were sighted during 271717 km of survey effort. In 4944 h of land-based observations, 2968 cetacean groups were detected. Twenty-four species were recorded: seven baleen whales, six beaked whales, eight dolphin species, Physeter macrocephalus, Kogia breviceps and K. sima. Overall, Delphinus delphis was the most frequently sighted species but its encounter rate decreased in June- November, coinciding with presence of Stenella frontalis in the region. Tursiops truncatus, P. macrocephalus and Grampus griseus were frequently encountered yearround, whereas large baleen whales showed a distinct peak in encounter rates in March-May. Mesoplodonts were fairly common and appear to be present throughout the year. These findings fill-in a significant gap in the knowledge of cetaceans occurring in a poorly studied region of the North Atlantic, providing much needed data to inform management initiatives.
  • Article
    North Atlantic right whale foraging ecology and its role in human-caused mortality
    (Inter-Research, 2017-10-13) Baumgartner, Mark F. ; Wenzel, Frederick W. ; Lysiak, Nadine S. J. ; Patrician, Melissa R.
    Endangered North Atlantic right whales Eubalaena glacialis suffer from unacceptably high rates of ship strikes and fishing gear entanglements, but little is known of the role that diving and foraging behavior plays in mediating human-caused mortality. We conducted a study of right whale foraging ecology by attaching tags to whales for short periods of time (hours), tracking their movements during daytime, and repeatedly sampling oceanographic conditions and prey distribution along the whales’ tracks. Right whales were tagged from late winter to late fall in 6 regions of the Gulf of Maine and southwestern Scotian Shelf from 2000 to 2010. The diving behavior of the tagged whales was governed by the vertical distribution of their primary prey, the copepod Calanus finmarchicus. On average, right whales tagged during spring spent 72% of their time in the upper 10 m (within the draft of most large commercial vessels), indicating the need for expanded ship speed restrictions in western Gulf of Maine springtime habitats. One out of every 4 whales dove to within 5 m of the sea floor during the short time they were tagged, spending as much as 45% of their total tagged time in this depth stratum. Right whales dove to the sea floor in each habitat studied except for one (where only 1 whale was tagged). This relatively high incidence of near-bottom diving raises serious concerns about the continued use of floating ground lines in pot and trap gear in coastal Maine and Canadian waters.
  • Article
    Low frequency vocalizations attributed to sei whales (Balaenoptera borealis)
    (Acoustical Society of America, 2008-08) Baumgartner, Mark F. ; Van Parijs, Sofie M. ; Wenzel, Frederick W. ; Tremblay, Christopher J. ; Esch, H. Carter ; Warde, Ann M.
    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.
  • Article
    Distribution of blue and sei whale vocalizations, and temperature - salinity characteristics from glider surveys in the Northern Chilean Patagonia mega-estuarine system
    (Frontiers Media, 2022-10-07) Buchan, Susannah J. ; Gutiérrez, Laura ; Baumgartner, Mark F. ; Stafford, Kathleen M. ; Ramirez, Nadin ; Pizarro, Oscar ; Cifuentes, Jose
    Northern Chilean Patagonia is a mega-estuarine system where oceanic waters mix with freshwater inputs in the coastal fjords, channels and gulfs. The aim of this study was to examine the distribution of blue and sei whales with respect to oceanographic conditions of the study area from the estuarine inner sea to the outer ocean. Ocean gliders were used, mounted with a hydrophone to determine acoustic presence of whales (Southeast Pacific and Antarctic blue whale song calls, and blue whales D-calls; sei whale downsweeps and upsweeps), and a temperature and salinity instrument. Four glider deployments were carried out in April 2018 and April-June 2019 navigating a total of 2817 kilometers during 2110 hours. To examine interannual variation, the average percentage of day with presence of calls was compared between years using the adjusted p-values for one-way ANOVA and descriptive statistics. To examine spatial variation between the hourly acoustic presence of blue whales and sei whales and temperature and salinity conditions, Generalized Linear Models (GLMs) were used. Salinities were higher in 2019 compared to 2018. Southeast Pacific blue whales produced song calls throughout the study area in both years, across estuarine and oceanic areas, but percentage of day with presence was higher in 2019 vs 2018. Percentage of day with presence of D-calls was similar between years, but higher in oceanic areas during both study periods. In contrast, the spatial pattern of sei whale acoustic presence was ambiguous and interannual variability was high, suggesting that sei whales preferred estuarine areas in 2018 and oceanic areas in 2019. We discuss possible explanations for observed acoustic presence in relation to foraging behavior and prey distribution.
  • Article
    Self-localization of buoyless fishing gear and other objects on the sea floor
    (Acoustical Society of America, 2021-08-05) Baumgartner, Mark F. ; Partan, Jim
    End lines used in commercial trap/pot fishing pose a significant entanglement risk to whales, sea turtles, and sharks. Removal of these ropes for buoyless fishing is being considered by the United States and Canadian governments, but a method to systematically locate the gear without an attached buoy is required. A method was developed for an acoustic modem to self-localize and broadcast its location to nearby ships to minimize gear conflict, optimize power consumption, and reduce lost gear. This method was implemented using a research modem that self-localized to within 5 m of its estimated location on the sea floor.
  • Article
    Acoustic presence and vocal activity of North Atlantic right whales in the New York Bight: Implications for protecting a critically endangered species in a human‐dominated environment
    (Wiley Open Access, 2022-10-27) Murray, Anita ; Rekdahl, Melinda L. ; Baumgartner, Mark F. ; Rosenbaum, Howard C.
    North Atlantic right whale (NARW) distribution shifts have led to increased presence in the US mid‐Atlantic, which includes the New York Bight (NYB), an area with substantial vessel traffic. NARW vessel strikes are mitigated by a seasonal management area (SMA) that is active November–April. Within the SMA, vessels ≥ 19.8 m must travel at ≤10 knots. However, until recently, surveys of the NYB were not conducted after the NARW distribution shifted. Thus, it was unclear whether the SMA captured NARW presence in the NYB. Outside the SMA, voluntary speed restrictions are implemented over a limited area when NARW calls are acoustically detected; therefore, it was important to quantify NARW vocal activity. Acoustic recordings (2016–2020) were analyzed to determine NARW presence, vocal states, and diel pattern of vocal activity. NARWs were detected outside SMA boundaries, and medium/high vocal states (21–69 calls over 3–6 h) occurred while the SMA was inactive. Therefore, the SMA spatiotemporal boundaries should be revised. Vocal activity was highest at night (22:00–1:00), and NARWs were acoustically detected when they were not detected by aerial surveys, illustrating acoustic detections are a viable method for triggering mitigation measures when NARWs are vocalizing but are not visually observed.
  • Article
    Associations between North Pacific right whales and their zooplanktonic prey in the southeastern Bering Sea
    (Inter-Research, 2013-09-17) Baumgartner, Mark F. ; Lysiak, Nadine S. J. ; Esch, H. Carter ; Zerbini, Alexandre N. ; Berchok, Catherine L. ; Clapham, Phillip J.
    Due to the seriously endangered status of North Pacific right whales Eubalaena japonica, an improved understanding of the environmental factors that influence the species’ distribution and occurrence is needed to better assess the effects of climate change and industrial activities on the population. Associations among right whales, zooplankton, and the physical environment were examined in the southeastern Bering Sea during the summers of 2008 and 2009. Sampling with nets, an optical plankton counter, and a video plankton recorder in proximity to whales as well as along cross-isobath surveys indicated that the copepod Calanus marshallae is the primary prey of right whales in this region. Acoustic detections of right whales from sonobuoys deployed during the cross-isobath surveys were strongly associated with C. marshallae abundance, and peak abundance estimates of C. marshallae in 2.5 m depth strata near a tagged right whale ranged as high as 106 copepods m-3. The smaller Pseudocalanus spp. was higher in abundance than C. marshallae in proximity to right whales, but significantly lower in biomass. High concentrations of C. marshallae occurred in both the surface and bottom layers of the highly stratified water column, but there was no evidence of diel vertical migration. Instead, occurrence of C. marshallae in the bottom layer was associated with elevated near-bottom light attenuance and chlorophyll fluorescence, suggesting C. marshallae may aggregate at depth while feeding on resuspended phytodetritus. Despite the occasional presence of strong horizontal gradients in hydrographic properties, no association was found between C. marshallae and either fronts or phytoplankton distribution.
  • Preprint
    Coping with copepods: do right whales (Eubalaena glacialis) forage visually in dark waters?
    ( 2017-02) Cronin, Thomas W. ; Fasick, Jeffry I. ; Schweikert, Lorian E. ; Johnsen, Sonke ; Kezmoh, Lorren J. ; Baumgartner, Mark F.
    North Atlantic right whales (Eubalaena glacialis) feed during the spring and early summer in marine waters off the northeast coast of North America. Their food primarily consists of planktonic copepods, Calanus finmarchicus, which they consume in large numbers by ram filter feeding. The coastal waters where these whales forage are turbid, but they successfully locate copepod swarms during the day at depths exceeding 100 m, where light is very dim and copepod patches may be difficult to see. Using models of E. glacialis visual sensitivity together with measurements of light in waters near Cape Cod where they feed and of light attenuation by living copepods in seawater, we evaluated the potential for visual foraging by these whales. Our results suggest that vision may be useful for finding copepod patches, particularly if E. glacialis searches overhead for silhouetted masses or layers of copepods. This should permit the whales to locate C. finmarchicus visually throughout most daylight hours at depths throughout their foraging range. Looking laterally, the whales might also be able to see copepod patches at short range near the surface.