Halpin
Patrick N.
Halpin
Patrick N.
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ArticleStriking 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.
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ArticleThe relationship among oceanography, prey fields, and beaked whale foraging habitat in the Tongue of the Ocean(Public Library of Science, 2011-04-27) Hazen, Elliott L. ; Nowacek, Douglas P. ; St. Laurent, Louis C. ; Halpin, Patrick N. ; Moretti, David J.Beaked whales, specifically Blainville's (Mesoplodon densirostris) and Cuvier's (Ziphius cavirostris), are known to feed in the Tongue of the Ocean, Bahamas. These whales can be reliably detected and often localized within the Atlantic Undersea Test and Evaluation Center (AUTEC) acoustic sensor system. The AUTEC range is a regularly spaced bottom mounted hydrophone array covering >350 nm2 providing a valuable network to record anthropogenic noise and marine mammal vocalizations. Assessments of the potential risks of noise exposure to beaked whales have historically occurred in the absence of information about the physical and biological environments in which these animals are distributed. In the fall of 2008, we used a downward looking 38 kHz SIMRAD EK60 echosounder to measure prey scattering layers concurrent with fine scale turbulence measurements from an autonomous turbulence profiler. Using an 8 km, 4-leaf clover sampling pattern, we completed a total of 7.5 repeat surveys with concurrently measured physical and biological oceanographic parameters, so as to examine the spatiotemporal scales and relationships among turbulence levels, biological scattering layers, and beaked whale foraging activity. We found a strong correlation among increased prey density and ocean vertical structure relative to increased click densities. Understanding the habitats of these whales and their utilization patterns will improve future models of beaked whale habitat as well as allowing more comprehensive assessments of exposure risk to anthropogenic sound.
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ArticleGoogle haul out : Earth observation imagery and digital aerial surveys in coastal wildlife management and abundance estimation(Oxford University Press, 2017-06-14) Moxley, Jerry ; Bogomolni, Andrea L. ; Hammill, Mike O. ; Moore, Kathleen M. T. ; Polito, Michael J. ; Sette, Lisa ; Sharp, W. Brian ; Waring, Gordon T. ; Gilbert, James R. ; Halpin, Patrick N. ; Johnston, David W.As the sampling frequency and resolution of Earth observation imagery increase, there are growing opportunities for novel applications in population monitoring. New methods are required to apply established analytical approaches to data collected from new observation platforms (e.g., satellites and unmanned aerial vehicles). Here, we present a method that estimates regional seasonal abundances for an understudied and growing population of gray seals (Halichoerus grypus) in southeastern Massachusetts, using opportunistic observations in Google Earth imagery. Abundance estimates are derived from digital aerial survey counts by adapting established correction-based analyses with telemetry behavioral observation to quantify survey biases. The result is a first regional understanding of gray seal abundance in the northeast US through opportunistic Earth observation imagery and repurposed animal telemetry data. As species observation data from Earth observation imagery become more ubiquitous, such methods provide a robust, adaptable, and cost-effective solution to monitoring animal colonies and understanding species abundances.
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ArticleTechniques 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.
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PreprintEvidence of resource partitioning between humpback and minke whales around the western Antarctic Peninsula( 2008-09-20) Friedlaender, Ari S. ; Lawson, Gareth L. ; Halpin, Patrick N.For closely related sympatric species to coexist, they must differ to some degree in their ecological requirements or niches (e.g., diets) to avoid inter-specific competition. Baleen whales in the Antarctic feed primarily on krill, and the large sympatric pre-whaling community suggests resource partitioning among these species or a non-limiting prey resource. In order to examine ecological differences between sympatric humpback and minke whales around the Western Antarctic Peninsula, we made measurements of the physical environment, observations of whale distribution, and concurrent acoustic measurements of krill aggregations. Mantel’s tests and Classification and regression tree models indicate both similarities and differences in the spatial associations between humpback and minke whales, environmental features, and prey. The data suggest (1) similarities (proximity to shore) and differences (prey abundance versus deep water temperatures) in horizontal spatial distribution patterns, (2) unambiguous vertical resource partitioning with minke whales associating with deeper krill aggregations across a range of spatial scales, and (3) that interference competition between these two species is unlikely. These results add to the paucity of ecological knowledge relating baleen whales and their prey in the Antarctic and should be considered in conservation and management efforts for Southern Ocean cetaceans and ecosystems.
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ArticleA three-dimensional mapping of the ocean based on environmental data(The Oceanography Society, 2017-03) Sayre, Roger ; Wright, Dawn J. ; Breyer, Sean P. ; Butler, Kevin A. ; Van Graafeiland, Keith ; Costello, Mark J. ; Harris, Peter T. ; Goodin, Kathleen L. ; Guinotte, John M. ; Basher, Zeenatul ; Kavanaugh, Maria T. ; Halpin, Patrick N. ; Monaco, Mark E. ; Cressie, Noel ; Aniello, Peter ; Frye, Charles E. ; Stephens, DrewThe existence, sources, distribution, circulation, and physicochemical nature of macroscale oceanic water bodies have long been a focus of oceanographic inquiry. Building on that work, this paper describes an objectively derived and globally comprehensive set of 37 distinct volumetric region units, called ecological marine units (EMUs). They are constructed on a regularly spaced ocean point-mesh grid, from sea surface to seafloor, and attributed with data from the 2013 World Ocean Atlas version 2. The point attribute data are the means of the decadal averages from a 57-year climatology of six physical and chemical environment parameters (temperature, salinity, dissolved oxygen, nitrate, phosphate, and silicate). The database includes over 52 million points that depict the global ocean in x, y, and z dimensions. The point data were statistically clustered to define the 37 EMUs, which represent physically and chemically distinct water volumes based on spatial variation in the six marine environmental characteristics used. The aspatial clustering to produce the 37 EMUs did not include point location or depth as a determinant, yet strong geographic and vertical separation was observed. Twenty-two of the 37 EMUs are globally or regionally extensive, and account for 99% of the ocean volume, while the remaining 15 are smaller and shallower, and occur around coastal features. We assessed the vertical distribution of EMUs in the water column and placed them into classical depth zones representing epipelagic (0 m to 200 m), mesopelagic (200 m to 1,000 m), bathypelagic (1,000 m to 4,000 m) and abyssopelagic (>4,000 m) layers. The mapping and characterization of the EMUs represent a new spatial framework for organizing and understanding the physical, chemical, and ultimately biological properties and processes of oceanic water bodies. The EMUs are an initial objective partitioning of the ocean using long-term historical average data, and could be extended in the future by adding new classification variables and by introducing functionality to develop time-specific EMU distribution maps. The EMUs are an open-access resource, and as both a standardized geographic framework and a baseline physicochemical characterization of the oceanic environment, they are intended to be useful for disturbance assessments, ecosystem accounting exercises, conservation priority setting, and marine protected area network design, along with other research and management applications.
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ArticleWhale 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.
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ArticleExtrapolating cetacean densities to quantitatively assess human impacts on populations in the high seas(John Wiley & Sons, 2017-04-28) Mannocci, Laura ; Roberts, Jason J. ; Miller, David L. ; Halpin, Patrick N.As human activities expand beyond national jurisdictions to the high seas, there is an increasing need to consider anthropogenic impacts to species inhabiting these waters. The current scarcity of scientific observations of cetaceans in the high seas impedes the assessment of population-level impacts of these activities. We developed plausible density estimates to facilitate a quantitative assessment of anthropogenic impacts on cetacean populations in these waters. Our study region extended from a well-surveyed region within the U.S. Exclusive Economic Zone into a large region of the western North Atlantic sparsely surveyed for cetaceans. We modeled densities of 15 cetacean taxa with available line transect survey data and habitat covariates and extrapolated predictions to sparsely surveyed regions. We formulated models to reduce the extent of extrapolation beyond covariate ranges, and constrained them to model simple and generalizable relationships. To evaluate confidence in the predictions, we mapped where predictions were made outside sampled covariate ranges, examined alternate models, and compared predicted densities with maps of sightings from sources that could not be integrated into our models. Confidence levels in model results depended on the taxon and geographic area and highlighted the need for additional surveying in environmentally distinct areas. With application of necessary caution, our density estimates can inform management needs in the high seas, such as the quantification of potential cetacean interactions with military training exercises, shipping, fisheries, and deep-sea mining and be used to delineate areas of special biological significance in international waters. Our approach is generally applicable to other marine taxa and geographic regions for which management will be implemented but data are sparse.
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ArticleDiel changes in humpback whale Megaptera novaeangliae feeding behavior in response to sand lance Ammodytes spp. behavior and distribution(Inter-Research, 2009-12-03) Friedlaender, Ari S. ; Hazen, Elliott L. ; Nowacek, Douglas P. ; Halpin, Patrick N. ; Ware, Colin ; Weinrich, Mason T. ; Hurst, Thomas P. ; Wiley, David N.Humpback whales Megaptera novaeangliae have adopted unique feeding strategies to take advantage of behavioral changes in their prey. However, logistical constraints have largely limited ecological analyses of these interactions. Our objectives were to (1) link humpback whale feeding behaviors to concurrent measurements of prey using scientific echo-sounders, and (2) quantify how sand lance behavior influences the feeding behaviors and foraging ecology of humpback whales. To measure, in fine detail, the 3-dimensional orientation and movement patterns of humpback whales underwater, we used a multi-sensor tag attached via suction cups (DTAG). We tested the specific hypothesis that the diel movement patterns of sand lance between bottom substrate and the water column correlates to changes between surface and bottom feeding strategies of humpback whales on Stellwagen Bank, MA. We collected over 96 h of both day- and nighttime data from 15 whales in 2006, and recorded 393 surface and 230 bottom feeding events. Individual whales exhibit both surface and bottom feeding behaviors, switching from one to the other in relation to changing light and prey conditions. Surface feeding behaviors were individually variable in their constitution but ubiquitously biased towards daylight hours, when prey was most abundant in the upper portion of the water column. Bottom feeding behavior occurred largely at night, coincident with when sand lance descend to seek refuge in the substrate. Our data provide novel insights into the behavioral ecology of humpback whales and their prey, indicating significant diel patterns in foraging behaviors concurrent with changes in prey behavior.