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Andrew J.

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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.
  • 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.
  • Article
    Exploring movement patterns and changing distributions of baleen whales in the western North Atlantic using a decade of passive acoustic data
    (Wiley, 2020-05-25) Davis, Genevieve E. ; Baumgartner, Mark F. ; Corkeron, Peter ; Bell, Joel ; Berchok, Catherine L. ; Bonnell, Julianne M. ; Bort Thornton, Jacqueline ; Brault, Solange ; Buchanan, Gary ; Cholewiak, Danielle ; Clark, Christopher W. ; Delarue, Julien ; Hatch, Leila ; Klinck, Holger ; Kraus, Scott D. ; Martin, Bruce ; Mellinger, David K. ; Moors-Murphy, Hilary ; Nieukirk, Sharon ; Nowacek, Douglas P. ; Parks, Susan E. ; Parry, Dawn ; Pegg, Nicole ; Read, Andrew J. ; Rice, Aaron N. ; Risch, Denise ; Scott, Alyssa ; Soldevilla, Melissa ; Stafford, Kathleen M. ; Stanistreet, Joy ; Summers, Erin ; Todd, Sean ; Van Parijs, Sofie M.
    Six baleen whale species are found in the temperate western North Atlantic Ocean, with limited information existing on the distribution and movement patterns for most. There is mounting evidence of distributional shifts in many species, including marine mammals, likely because of climate‐driven changes in ocean temperature and circulation. Previous acoustic studies examined the occurrence of minke (Balaenoptera acutorostrata ) and North Atlantic right whales (NARW; Eubalaena glacialis ). This study assesses the acoustic presence of humpback (Megaptera novaeangliae ), sei (B. borealis ), fin (B. physalus ), and blue whales (B. musculus ) over a decade, based on daily detections of their vocalizations. Data collected from 2004 to 2014 on 281 bottom‐mounted recorders, totaling 35,033 days, were processed using automated detection software and screened for each species' presence. A published study on NARW acoustics revealed significant changes in occurrence patterns between the periods of 2004–2010 and 2011–2014; therefore, these same time periods were examined here. All four species were present from the Southeast United States to Greenland; humpback whales were also present in the Caribbean. All species occurred throughout all regions in the winter, suggesting that baleen whales are widely distributed during these months. Each of the species showed significant changes in acoustic occurrence after 2010. Similar to NARWs, sei whales had higher acoustic occurrence in mid‐Atlantic regions after 2010. Fin, blue, and sei whales were more frequently detected in the northern latitudes of the study area after 2010. Despite this general northward shift, all four species were detected less on the Scotian Shelf area after 2010, matching documented shifts in prey availability in this region. A decade of acoustic observations have shown important distributional changes over the range of baleen whales, mirroring known climatic shifts and identifying new habitats that will require further protection from anthropogenic threats like fixed fishing gear, shipping, and noise pollution.
  • Article
    Techniques for cetacean–habitat modeling
    (Inter-Research, 2006-04-03) Redfern, J. V. ; Ferguson, M. C. ; Becker, E. A. ; Hyrenbach, K. D. ; Good, Caroline P. ; Barlow, Jay ; Kaschner, K. ; Baumgartner, Mark F. ; Forney, K. A. ; Ballance, L. T. ; Fauchald, P. ; Halpin, Patrick N. ; Hamazaki, T. ; Pershing, Andrew J. ; Qian, Song S. ; Read, Andrew J. ; Reilly, S. B. ; Torres, Leigh ; Werner, Francisco E.
    Cetacean–habitat modeling, although still in the early stages of development, represents a potentially powerful tool for predicting cetacean distributions and understanding the ecological processes determining these distributions. Marine ecosystems vary temporally on diel to decadal scales and spatially on scales from several meters to 1000s of kilometers. Many cetacean species are wide-ranging and respond to this variability by changes in distribution patterns. Cetacean–habitat models have already been used to incorporate this variability into management applications, including improvement of abundance estimates, development of marine protected areas, and understanding cetacean–fisheries interactions. We present a review of the development of cetacean–habitat models, organized according to the primary steps involved in the modeling process. Topics covered include purposes for which cetacean–habitat models are developed, scale issues in marine ecosystems, cetacean and habitat data collection, descriptive and statistical modeling techniques, model selection, and model evaluation. To date, descriptive statistical techniques have been used to explore cetacean–habitat relationships for selected species in specific areas; the numbers of species and geographic areas examined using computationally intensive statistic modeling techniques are considerably less, and the development of models to test specific hypotheses about the ecological processes determining cetacean distributions has just begun. Future directions in cetacean–habitat modeling span a wide range of possibilities, from development of basic modeling techniques to addressing important ecological questions.
  • Article
    Whale distribution in relation to prey abundance and oceanographic processes in shelf waters of the Western Antarctic Peninsula
    (Inter-Research, 2006-07-18) Friedlaender, Ari S. ; Halpin, Patrick N. ; Qian, Song S. ; Lawson, Gareth L. ; Wiebe, Peter H. ; Thiele, Deb ; Read, Andrew J.
    The Western Antarctic Peninsula (WAP) is a biologically rich area supporting large standing stocks of krill and top predators (including whales, seals and seabirds). Physical forcing greatly affects productivity, recruitment, survival and distribution of krill in this area. In turn, such interactions are likely to affect the distribution of baleen whales. The Southern Ocean GLOBEC research program aims to explore the relationships and interactions between the environment, krill and predators around Marguerite Bay (WAP) in autumn 2001 and 2002. Bathymetric and environmental variables including acoustic backscattering as an indicator of prey abundance were used to model whale distribution patterns. We used an iterative approach employing (1) classification and regression tree (CART) models to identify oceanographic and ecological variables contributing to variability in humpback Megaptera novaeangliae and minke Balaenoptera acutorstrata whale distribution, and (2) generalized additive models (GAMs) to elucidate functional ecological relationships between these variables and whale distribution. The CART models indicated that the cetacean distribution was tightly coupled with zooplankton acoustic volume backscatter in the upper (25 to 100 m), and middle (100 to 300 m) portions of the water column. Whale distribution was also related to distance from the ice edge and bathymetric slope. The GAMs indicated a persistent, strong, positive relationship between increasing zooplankton volume and whale relative abundance. Furthermore, there was a lower limit for averaged acoustic volume backscatter of zooplankton below which the relationship between whales and prey was not significant. The GAMs also supported an annual relationship between whale distribution, distance from the ice edge and bathymetric slope, suggesting that these are important features for aggregating prey. Our results demonstrate that during the 2 yr study, whales were consistently and predictably associated with the distribution of zooplankton. Thus, humpback and minke whales may be able to locate physical features and oceanographic processes that enhance prey aggregation.
  • Article
    Seasonal gain in body condition of foraging humpback whales along the Western Antarctic Peninsula
    (Frontiers Media, 2022-11-21) Bierlich, K. C. ; Hewitt, Joshua ; Schick, Robert S. ; Pallin, Logan ; Dale, Julian ; Friedlaender, Ari S. ; Christiansen, Fredrik ; Sprogis, Kate R. ; Dawn, Allison H. ; Bird, Clara N. ; Larsen, Gregory D. ; Nichols, Ross ; Shero, Michelle R. ; Goldbogen, Jeremy ; Read, Andrew J. ; Johnston, David W.
    Most baleen whales are capital breeders that use stored energy acquired on foraging grounds to finance the costs of migration and reproduction on breeding grounds. Body condition reflects past foraging success and can act as a proxy for individual fitness. Hence, monitoring the seasonal gain in body condition of baleen whales while on the foraging grounds can inform how marine mammals support the costs of migration, growth, and reproduction, as well as the nutritional health of the overall population. Here, we use photogrammetry from drone-based imagery to examine how the body condition of humpback whales (Megaptera novaeangliae) changed over the foraging season (November to June) along the Western Antarctic Peninsula (WAP) from 2017 to 2019. This population (IWC stock G) is recovering from past whaling and is growing rapidly, providing an opportunity to study how whales store energy in a prey-rich environment. We used a body area index (BAI) to estimate changes in body condition and applied a Bayesian approach to incorporate measurement uncertainty associated with different drone types used for data collection. We used biopsy samples to determine sex and pregnancy status, and a length-based maturity classification to assign reproductive classes (n= 228; calves = 31, juveniles = 82, lactating females = 31, mature males = 12, mature unknown sex = 56, non-pregnant females = 12, pregnant females = 3, pregnant & lactating females = 1). Average BAI increased linearly over the feeding season for each reproductive class. Lactating females had lower BAI compared to other mature whales late in the season, reflecting the high energetic costs of nursing a calf. Mature males and non-pregnant females had the highest BAI values. Calves and juvenile whales exhibited an increase in BAI but not structural size (body length) over the feeding season. The body length of lactating mothers was positively correlated with the body length of their calves, but no relationship was observed between the BAI of mothers and their calves. Our study establishes a baseline for seasonal changes in the body condition for this humpback whale population, which can help monitor future impacts of disturbance and climate change.
  • Article
    Food habits of Sowerby’s beaked whales (Mesoplodon bidens) taken in the pelagic drift gillnet fishery of the western North Atlantic
    (National Marine Fisheries Service, NOAA, 2013-08) Wenzel, Frederick W. ; Polloni, Pamela T. ; Craddock, James E. ; Gannon, Damon P. ; Nicolas, John R. ; Read, Andrew J. ; Rosel, Patricia E.
    We describe the food habits of the Sowerby’s beaked whale (Mesoplodon bidens) from observations of 10 individuals taken as bycatch in the pelagic drift gillnet fishery for Swordfish (Xiphias gladius) in the western North Atlantic and 1 stranded individual from Kennebunk, Maine. The stomachs of 8 bycaught whales were intact and contained prey. The diet of these 8 whales was dominated by meso- and benthopelagic fishes that composed 98.5% of the prey items found in their stomachs and cephalopods that accounted for only 1.5% of the number of prey. Otoliths and jaws representing at least 31 fish taxa from 15 families were present in the stomach contents. Fishes, primarily from the families Moridae (37.9% of prey), Myctophidae (22.9%), Macrouridae (11.2%), and Phycidae (7.2%), were present in all 8 stomachs. Most prey were from 5 fish taxa: Shortbeard Codling (Laemonema barbatulum) accounted for 35.3% of otoliths, Cocco’s Lanternfish (Lobianchia gemellarii) contributed 12.9%, Marlin-spike (Nezumia bairdii) composed 10.8%, lanternfishes (Lampanyctus spp.) accounted for 8.4%; and Longfin Hake (Phycis chesteri) contributed 6.7%. The mean number of otoliths per stomach was 1196 (range: 327–3452). Most of the fish prey found in the stomachs was quite small, ranging in length from 4.0 to 27.7 cm. We conclude that the Sowerby’s beaked whales that we examined in this study fed on large numbers of relatively small meso and benthopelagic fishes that are abundant along the slope and shelf break of the western North Atlantic.