The largest ever Ebola virus disease outbreak is ravaging West Africa. The constellation of little public health infrastructure, low levels of health literacy, limited acute care and infection ...prevention and control resources, densely populated areas, and a highly transmissible and lethal viral infection have led to thousands of confirmed, probable, or suspected cases thus far. Ebola virus disease is characterized by a febrile severe illness with profound gastrointestinal manifestations and is complicated by intravascular volume depletion, shock, profound electrolyte abnormalities, and organ dysfunction. Despite no proven Ebola virus-specific medical therapies, the potential effect of supportive care is great for a condition with high baseline mortality and one usually occurring in resource-constrained settings. With more personnel, basic monitoring, and supportive treatment, many of the sickest patients with Ebola virus disease do not need to die. Ebola virus disease represents an illness ready for a paradigm shift in care delivery and outcomes, and the profession of critical care medicine can and should be instrumental in helping this happen.
Mammals host diverse bacterial and archaeal symbiont communities (i.e. microbiomes) that play important roles in digestive and immune system functioning, yet cetacean microbiomes remain largely ...unexplored, in part due to sample collection difficulties. Here, fecal samples from stranded pygmy (Kogia breviceps) and dwarf (K. sima) sperm whales were used to characterize the gut microbiomes of two closely-related species with similar diets. 16S rRNA gene sequencing revealed diverse microbial communities in kogiid whales dominated by Firmicutes and Bacteroidetes. Core symbiont taxa were affiliated with phylogenetic lineages capable of fermentative metabolism and sulfate respiration, indicating potential symbiont contributions to energy acquisition during prey digestion. The diversity and phylum-level composition of kogiid microbiomes differed from those previously reported in toothed whales, which exhibited low diversity communities dominated by Proteobacteria and Actinobacteria. Community structure analyses revealed distinct gut microbiomes in K. breviceps and K. sima, driven by differential relative abundances of shared taxa, and unique microbiomes in kogiid hosts compared to other toothed and baleen whales, driven by differences in symbiont membership. These results provide insight into the diversity, composition and structure of kogiid gut microbiomes and indicate that host identity plays an important role in structuring cetacean microbiomes, even at fine-scale taxonomic levels.
Cetaceans are protected worldwide but vulnerable to incidental harm from an expanding array of human activities at sea. Managing potential hazards to these highly-mobile populations increasingly ...requires a detailed understanding of their seasonal distributions and habitats. Pursuant to the urgent need for this knowledge for the U.S. Atlantic and Gulf of Mexico, we integrated 23 years of aerial and shipboard cetacean surveys, linked them to environmental covariates obtained from remote sensing and ocean models, and built habitat-based density models for 26 species and 3 multi-species guilds using distance sampling methodology. In the Atlantic, for 11 well-known species, model predictions resembled seasonal movement patterns previously suggested in the literature. For these we produced monthly mean density maps. For lesser-known taxa, and in the Gulf of Mexico, where seasonal movements were less well described, we produced year-round mean density maps. The results revealed high regional differences in small delphinoid densities, confirmed the importance of the continental slope to large delphinoids and of canyons and seamounts to beaked and sperm whales, and quantified seasonal shifts in the densities of migratory baleen whales. The density maps, freely available online, are the first for these regions to be published in the peer-reviewed literature.
Whaling has decimated North Atlantic right whales Eubalaena glacialis (NARW) since the 11th century and southern right whales E. australis (SRW) since the 19th century. Today, NARWs are Critically ...Endangered and decreasing, whereas SRWs are recovering. We review NARW health assessment literature, NARW Consortium databases, and efforts and limitations to monitor individual and species health, survival, and fecundity. Photographs are used to track individual movement and external signs of health such as evidence of vessel and entanglement trauma. Post-mortem examinations establish cause of death and determine organ pathology. Photogrammetry is used to assess growth rates and body condition. Samples of blow, skin, blubber, baleen and feces quantify hormones that provide information on stress, reproduction, and nutrition, identify microbiome changes, and assess evidence of infection. We also discuss models of the population consequences of multiple stressors, including the connection between human activities (e.g. entanglement) and health. Lethal and sublethal vessel and entanglement trauma have been identified as major threats to the species. There is a clear and immediate need for expanding trauma reduction measures. Beyond these major concerns, further study is needed to evaluate the impact of other stressors, such as pathogens, microbiome changes, and algal and industrial toxins, on NARW reproductive success and health. Current and new health assessment tools should be developed and used to monitor the effectiveness of management measures and will help determine whether they are sufficient for a substantive species recovery.
How to Build a Deep Diver Pabst, D. Ann; McLellan, William A.; Rommel, Sentiel A.
Integrative and comparative biology,
12/2016, Letnik:
56, Številka:
6
Journal Article
Recenzirano
Odprti dostop
Mesoplodont beaked whales are extreme divers, diving for over 45 mins and to depths of over 800 m. These dives are of similar depth and duration to those of the giant sperm whale (Physeter ...macrocephalus) whose body mass can be 50 times larger. Velten et al. (2013) provided anatomical data that demonstrated that on-board oxygen stores were sufficient to aerobically support the extreme dives of mesoplodonts if their diving metabolic rates are low. Because no physiological data yet exist, we utilized an anatomical approach—the body composition technique—to examine the relative metabolic rates of mesoplodonts. We utilized a systematic mass dissection protocol to compare the body composition of mesoplodonts with those of two short duration, shallow divers—the harbor porpoise (Phocoena phocoena) and bottlenose dolphin (Tursiops truncatus). We then investigated the body composition of two other extreme divers, the southern elephant seal (Mirounga leonina) and P. macrocephalus using data from the literature. Our results demonstrate that extreme divers invest a smaller percentage of their total body mass (TBM) in metabolically expensive brain and viscera, and a larger percent of their TBM in inexpensive integument, bone, and muscle, than do the shallow divers. Deep divers also share features of their locomotor muscle that contribute to relatively low tissue metabolic rates and high oxygen storage capacity, including large muscle fiber diameters, low mitochondrial volume densities, and high myoglobin concentrations. One feature of the locomotor muscle of mesoplodonts, though, is unique among deep divers investigated to date. Rather than having an endurance athlete’s muscle fiber profile, dominated by slow oxidative fibers, mesoplodonts possess a sprinter’s profile, dominated by fast glycolytic fibers. Velten et al. (2013) hypothesized that these fibers are likely inactive during routine swimming and provide a large, metabolically inexpensive oxygen store for the slow oxidative fibers to aerobically power swimming. We suggest that future anatomical analyses, coupled with performance data transduced through tagging studies, will enhance our understanding of the extreme diving capabilities of marine mammals.
Aim
The aim of this study was to determine if marine mammals follow ecogeographic rules. We examined Bergmann's rule and Allen's rule in two pilot whale species with contrasting latitudinal ...distributions.
Location
Northwest Atlantic Ocean.
Taxon
Globicephala spp.
Methods
We analysed morphometric data collected from strandings of short‐ and long‐finned pilot whales in the Northwest Atlantic Ocean to assess intraspecific and interspecific variation in surface area to volume ratios (SA:V) of the body core and appendage surface area relative to body core SA (normalized appendage SA) using a novel 3D modelling method.
Results
Our results suggest that ecogeographic variation in morphometrics between the two pilot whale species is consistent with morphological adaptations required to balance heat conservation and heat dissipation. Interspecific differences in morphology supported Bergmann's rule for fully grown individuals: the more temperate long‐finned pilot whale had a larger body size and lower body core SA:V than the short‐finned pilot whale, which has a more tropical distribution. Allen's rule was not supported; when all appendages were considered together, long‐finned pilot whales had larger normalized SA than short‐finned pilot whales. However, the pectoral flippers were the primary driver of this relationship; while long‐finned pilot whales had proportionally larger pectoral flippers, short‐finned pilot whales had proportionally larger dorsal fins and flukes. In addition, larger long‐finned pilot whales (i.e. males and mature individuals) had proportionally larger pectoral flippers than smaller long‐finned pilot whales.
Main Conclusions
Pilot whales follow Bergmann's rule but do not follow Allen's rule when fully mature. Thinly insulated appendages in marine mammals can be used to dissipate heat as the core warms, and larger and better insulated marine mammals may require relatively larger appendages in order to offload heat and thermoregulate effectively. Our results provide novel insight into ecogeographic rules and suggest that species in higher latitude climates towards the poles will demonstrate tradeoffs between core body heat conservation and appendage heat dissipation.
Post-mortem examination of dead and live stranded beach-cast pinnipeds and cetaceans for determination of a cause of death provides valuable information for the management, mitigation and prosecution ...of unintentional and sometimes malicious human impacts, such as vessel collision, fishing gear entanglement and gunshot. Delayed discovery, inaccessibility, logistics, human safety concerns, and weather make these events challenging. Over the past 3 decades, in response to public concern and federal and state or provincial regulations mandating such investigations to inform mitigation efforts, there has been an increasing effort to objectively and systematically investigate these strandings from a diagnostic and forensic perspective. This Theme Section provides basic investigative methods, and case definitions for each of the more commonly recognized case presentations of human interactions in pinnipeds and cetaceans. Wild animals are often adversely affected by factors such as parasitism, anthropogenic contaminants, biotoxins, subclinical microbial infections and competing habitat uses, such as prey depletion and elevated background and episodic noise. Understanding the potential contribution of these subclinical factors in predisposing or contributing to a particular case of trauma of human origin is hampered, especially where putrefaction is significant and resources as well as expertise are limited. These case criteria descriptions attempt to acknowledge those confounding factors to enable an appreciation of the significance of the observed human-derived trauma in that broader context where possible.
Adaptive approaches are needed to effectively manage dynamic marine systems, and ecological forecasts can help managers anticipate when and where conservation issues are likely to arise in the ...future. The recent development of subseasonal global environmental forecasts provides an opportunity to inform management by forecasting species distributions in advance over operational timeframes. We demonstrate the utility of environmental forecasts for managing marine mammals by integrating species distribution models with subseasonal forecasts to predict the arrival of migratory humpback whales (Megaptera novaeangliae) at foraging grounds in the Northeast US. Environmental forecasts showed high model skill at lead times of up to 2 weeks and resulting humpback whale models performed well in predicting humpback arrival. Forecasts of whale distribution can shape management efforts to minimize both impacts on whales and economic costs. Applying subseasonal forecasts to anticipate future risk presents a powerful tool for the dynamic management of marine mammals.
Front Ecol Environ 2022;
United States and Canadian governments have responded to legal requirements to reduce human-induced whale mortality via vessel strikes and entanglement in fishing gear by implementing a suite of ...regulatory actions. We analyzed the spatial and temporal patterns of mortality of large whales in the Northwest Atlantic (23.5° N to 48.0° N), 1970 through 2009, in the context of management changes. We used a multinomial logistic model fitted by maximum likelihood to detect trends in cause-specific mortalities with time. We compared the number of human-caused mortalities with U.S. federally established levels of potential biological removal (i.e., species-specific sustainable human-caused mortality). From 1970 through 2009, 1762 mortalities (all known) and serious injuries (likely fatal) involved 8 species of large whales. We determined cause of death for 43% of all mortalities; of those, 67% (502) resulted from human interactions. Entanglement in fishing gear was the primary cause of death across all species (n = 323), followed by natural causes (n = 248) and vessel strikes (n = 171). Established sustainable levels of mortality were consistently exceeded in 2 species by up to 650%. Probabilities of entanglement and vessel-strike mortality increased significantly from 1990 through 2009. There was no significant change in the local intensity of all or vessel-strike mortalities before and after 2003, the year after which numerous mitigation efforts were enacted. So far, regulatory efforts have not reduced the lethal effects of human activities to large whales on a population-range basis, although we do not exclude the possibility of success of targeted measures for specific local habitats that were not within the resolution of our analyses. It is unclear how shortfalls in management design or compliance relate to our findings. Analyses such as the one we conducted are crucial in critically evaluating wildlife-management decisions. The results of these analyses can provide managers with direction for modifying regulated measures and can be applied globally to mortality-driven conservation issues. Los gobiernos de Estados Unidos y Canadá han respondido a requerimientos legales para reducir la mortalidad de ballenas inducida por humanos por medio de impacto con embarcaciones y enmarañamiento en artes de pesca mediante la implementación de un conjunto de acciones reguladoras. Analizamos los patrones espaciales y temporales de la mortalidad de ballenas mayores en el Atlántico Noroccidental (23.5° N a 48.0° N), de 1970 a 2009, en el contexto de cambios de manejo. Utilizamos un modelo logístico multinomial ajustado por la máxima probabilidad de detección de tendencias en mortalidades por causa específica en el tiempo. Comparamos el número de muertes provocadas por humanos con los niveles de remoción biológica potencial (i.e., mortalidad específica provocada por humanos sustentable). De 1970 a 2009, hubo 1762 muertes (conocidas) y lesiones serias (casi fatales) involucrando 8 especies de ballenas mayores. Determinamos la causa de 43% de todas las muertes; de ellas, 67% (502) resultaron de interacciones humanas. El enmarañamiento en artes de pesca fue la causa principal de muerte en todas las especies (n = 323), seguida de causas naturales (n = 248) e impacto de embarcaciones (n = 171). Los niveles sustentables de mortalidad establecidos fueron excedidos consistentemente hasta en 650% en 2 especies. Las probabilidades de muerte por enmarañamiento y por impacto de embarcaciones incrementaron significativamente de 1990 a 2009. No hubo cambio significativo en la intensidad local de mortalidad por todas las causas o por impacto de embarcaciones antes y después de 2003, año en el que se implementaron numerosos esfuerzos de mitigación. Hasta ahora, los esfuerzos regulatorios no han reducido los efectos letales de las actividades humanas sobre las ballenas a nivel de población, aunque no excluimos la posibilidad de éxito de medidas enfocadas a hábitats locales específicos que no estuvieron dentro de la resolución de nuestro análisis. No es claro como se relacionan con nuestros resultados las deficiencias en el diseño o implementación del manejo. Análisis como el que realizamos son cruciales para la evaluación crítica de decisiones para el manejo de vida silvestre, y los resultados de estos análisis pueden proporcionar directrices a los manejadores para que modifiquen medidas regulatorias y puedan ser aplicadas globalmente en temas de conservación relacionadas con mortalidad.
Internal pressures change throughout a cetacean's body during swimming or diving, and uneven pressures between the thoracic and abdominal compartments can affect the cardiovascular system. Pressure ...differentials could arise from ventral compression on each fluke downstroke or by a faster equilibration of the abdominal compartment with changing ambient ocean pressures compared with the thoracic compartment. If significant pressure differentials do develop, we would expect the morphology of the diaphragm to adapt to its
loading. Here, we tested the hypothesis that significant pressure differentials develop between the thoracic and abdominal cavities in diving cetaceans by examining diaphragms from several cetacean and pinniped species. We found that: (1) regions of cetacean diaphragms possess subserosal collagen fibres that would stabilize the diaphragm against craniocaudal stretch; (2) subserosal collagen covers 5-60% of the thoracic diaphragm surface, and area correlates strongly with published values for swimming speed of each cetacean species (
<0.001); and (3) pinnipeds, which do not locomote by vertical fluking, do not possess this subserosal collagen. These results strongly suggest that this collagen is associated with loads experienced during a dive, and they support the hypothesis that diving cetaceans experience periods during which abdominal pressures significantly exceed thoracic pressures. Our results are consistent with the generation of pressure differentials by fluking and by different compartmental equilibration rates. Pressure differentials during diving would affect venous and arterial perfusion and alter transmural pressures in abdominal arteries.
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