Wenzel Frederick W.
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PreprintEvidence 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. ).
PreprintStatic inflation and deflation pressure–volume curves from excised lungs of marine mammals( 2011-06-28) Fahlman, Andreas ; Loring, Stephen H. ; Ferrigno, Massimo ; Moore, Colby D. ; Early, Greg A. ; Niemeyer, Misty E. ; Lentell, Betty J. ; Wenzel, Frederick W. ; Joy, Ruth ; Moore, Michael J.Excised lungs from 8 marine mammal species (harp [Pagophilus groenlandicus], harbor [Phoca vitulina], and gray seal [Halichoerus grypus], Atlantic white-sided [Lagenorhynchus acutus], common [Delphinus delphis] and Risso's dolphin [Grampus griseus], long finned pilot whale [Globicephala melas], and harbor porpoise [Phocoena phocoena]) were used to determine minimum air volume of the relaxed lung (MAV, n = 15) and the elastic properties (pressure-volume curves, n = 24) of the respiratory system, and total lung capacity (TLC). Our data indicate that mass-specific TLC (sTLC, l • kg-1) does not differ between species or groups (odontocete vs. phocid) and agree with that estimated (TLCest) from body mass (Mb) by: TLCest = 0.135 • Mb 0.92. Measured MAV was on average 7% of TLC, with a range from 0% to 16%. The pressure-volume curves were similar among species on inflation but diverged during deflation in phocids as compared with odontocetes. These differences provide a structural basis for observed species differences in depth at which lungs collapse and gas exchange ceases.
ArticleNorth 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.
ArticleLow 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.
ArticleDiscrimination between bycatch and other causes of cetacean and pinniped stranding(Inter-Research, 2018-01-31) Bernaldo de Quirós, Yara ; Hartwick, Meghan ; Rotstein, David S. ; Garner, Michael M. ; Bogomolni, Andrea L. ; Greer, William ; Niemeyer, Misty E. ; Early, Greg A. ; Wenzel, Frederick W. ; Moore, Michael J.The challenge of identifying cause of death in discarded bycaught marine mammals stems from a combination of the non-specific nature of the lesions of drowning, the complex physiologic adaptations unique to breath-holding marine mammals, lack of case histories, and the diverse nature of fishing gear. While no pathognomonic lesions are recognized, signs of acute external entanglement, bulging or reddened eyes, recently ingested gastric contents, pulmonary changes, and decompression-associated gas bubbles have been identified in the condition of peracute underwater entrapment (PUE) syndrome in previous studies of marine mammals. We reviewed the gross necropsy and histopathology reports of 36 cetaceans and pinnipeds including 20 directly observed bycaught and 16 live stranded animals that were euthanized between 2005 and 2011 for lesions consistent with PUE. We identified 5 criteria which present at significantly higher rates in bycaught marine mammals: external signs of acute entanglement, red or bulging eyes, recently ingested gastric contents, multi-organ congestion, and disseminated gas bubbles detected grossly during the necropsy and histologically. In contrast, froth in the trachea or primary bronchi, and lung changes (i.e. wet, heavy, froth, edema, congestion, and hemorrhage) were poor indicators of PUE. This is the first study that provides insight into the different published parameters for PUE in bycatch. For regions frequently confronted by stranded marine mammals with non-specific lesions, this could potentially aid in the investigation and quantification of marine fisheries interactions.
ArticleFood habits of Atlantic white-sided dolphins (Lagenorhynchus acutus) off the coast of New England(U.S. Dept. of Commerce, NOAA NMFS, 2009-07) Craddock, James E. ; Polloni, Pamela T. ; Hayward, Brett ; Wenzel, Frederick W.Although the Atlantic white-sided dolphin (Lagenorhynchus acutus) is one of the most common dolphins off New England, little has been documented about its diet in the western North Atlantic Ocean. Current federal protection of marine mammals limits the supply of animals for investigation to those incidentally caught in the nets of commercial fishermen with observers aboard. Stomachs of 62 L. acutus were examined; of these 62 individuals, 28 of them were caught by net and 34 were animals stranded on Cape Cod. Most of the net-caught L. acutus were from the deeper waters of the Gulf of Maine. A single stomach was from the continental slope south of Georges Bank. At least twenty-six fish species and three cephalopod species were eaten. The predominant prey were silver hake (Merluccius bilinearis), spoonarm octopus (Bathypolypus bairdii), and haddock (Melanogrammus aeglefinus). The stomach from a net-caught L. acutus on the continental slope contained 7750 otoliths of the Madeira lanternfish (Ceratoscopelus maderensis). Sand lances (Ammodytes spp.) were the most abundant (541 otoliths) species in the stomachs of stranded L. acutus. Seasonal variation in diet was indicated; pelagic Atlantic herring (Clupea harengus) was the most important prey in summer, but was rare in winter. The average length of fish prey was approximately 200 mm, and the average mantle length of cephalopod prey was approximately 50 mm.
ArticleAn assessment of temporal, spatial and taxonomic trends in harmful algal toxin exposure in stranded marine mammals from the US New England coast(Public Library of Science, 2021-01-06) Fire, Spencer E. ; Bogomolni, Andrea L. ; DiGiovanni, Robert A., Jr. ; Early, Greg A. ; Leighfield, Tod A. ; Matassa, Keith A. ; Miller, Glenn A. ; Moore, Kathleen M. T. ; Moore, Michael J. ; Niemeyer, Misty E. ; Pugliares, Katie R. ; Wang, Zhihong ; Wenzel, Frederick W.Despite a long-documented history of severe harmful algal blooms (HABs) in New England coastal waters, corresponding HAB-associated marine mammal mortality events in this region are far less frequent or severe relative to other regions where HABs are common. This long-term survey of the HAB toxins saxitoxin (STX) and domoic acid (DA) demonstrates significant and widespread exposure of these toxins in New England marine mammals, across multiple geographic, temporal and taxonomic groups. Overall, 19% of the 458 animals tested positive for one or more toxins, with 15% and 7% testing positive for STX and DA, respectively. 74% of the 23 different species analyzed demonstrated evidence of toxin exposure. STX was most prevalent in Maine coastal waters, most frequently detected in common dolphins (Delphinus delphis), and most often detected during July and October. DA was most prevalent in animals sampled in offshore locations and in bycaught animals, and most frequently detected in mysticetes, with humpback whales (Megaptera novaeangliae) testing positive at the highest rates. Feces and urine appeared to be the sample matrices most useful for determining the presence of toxins in an exposed animal, with feces samples having the highest concentrations of STX or DA. No relationship was found between the bloom season of toxin-producing phytoplankton and toxin detection rates, however STX was more likely to be present in July and October. No relationship between marine mammal dietary preference and frequency of toxin detection was observed. These findings are an important part of a framework for assessing future marine mammal morbidity and mortality events, as well as monitoring ecosystem health using marine mammals as sentinel organisms for predicting coastal ocean changes.
ArticleFood 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.