Raverty Stephen A.

No Thumbnail Available
Last Name
First Name
Stephen A.

Search Results

Now showing 1 - 3 of 3
  • Article
    Assessing North Atlantic Right whale health: a review of threats, and development of tools critical for conservation of the species
    (Inter Research, 2021-02-25) Moore, Michael J. ; Rowles, Teresa K. ; Fauquier, Deborah A. ; Baker, Jason T. ; Biedron, Ingrid S. ; Durban, John W. ; Hamilton, Philip K. ; Henry, Allison G. ; Knowlton, Amy R. ; McLellan, William A. ; Miller, Carolyn A. ; Pace, Richard M., III ; Pettis, Heather M. ; Raverty, Stephen A. ; Rolland, Rosalind M. ; Schick, Robert S. ; Sharp, Sarah M. ; Smith, Cynthia R. ; Thomas, Len ; van der Hoop, Julie M. ; Ziccard, Michael H.
    Whaling 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.
  • Article
    Criteria and case definitions for serious injury and death of pinnipeds and cetaceans caused by anthropogenic trauma
    (Inter-Research, 2013-04-11) Moore, Michael J. ; van der Hoop, Julie ; Barco, Susan G. ; Costidis, Alexander M. ; Gulland, Frances M. ; Jepson, Paul D. ; Moore, Kathleen M. T. ; Raverty, Stephen A. ; McLellan, William A.
    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.
  • Article
    Overcoming the challenges of studying conservation physiology in large whales : a review of available methods
    (Oxford University Press, 2013-05-15) Hunt, Kathleen E. ; Moore, Michael J. ; Rolland, Rosalind M. ; Kellar, Nicholas M. ; Hall, Ailsa J. ; Kershaw, Joanna ; Raverty, Stephen A. ; Davis, Cristina E. ; Yeates, Laura C. ; Fauquier, Deborah A. ; Rowles, Teresa K. ; Kraus, Scott D.
    Large whales are subjected to a variety of conservation pressures that could be better monitored and managed if physiological information could be gathered readily from free-swimming whales. However, traditional approaches to studying physiology have been impractical for large whales, because there is no routine method for capture of the largest species and there is presently no practical method of obtaining blood samples from free-swimming whales. We review the currently available techniques for gathering physiological information on large whales using a variety of non-lethal and minimally invasive (or non-invasive) sample matrices. We focus on methods that should produce information relevant to conservation physiology, e.g. measures relevant to stress physiology, reproductive status, nutritional status, immune response, health, and disease. The following four types of samples are discussed: faecal samples, respiratory samples (‘blow’), skin/blubber samples, and photographs. Faecal samples have historically been used for diet analysis but increasingly are also used for hormonal analyses, as well as for assessment of exposure to toxins, pollutants, and parasites. Blow samples contain many hormones as well as respiratory microbes, a diverse array of metabolites, and a variety of immune-related substances. Biopsy dart samples are widely used for genetic, contaminant, and fatty-acid analyses and are now being used for endocrine studies along with proteomic and transcriptomic approaches. Photographic analyses have benefited from recently developed quantitative techniques allowing assessment of skin condition, ectoparasite load, and nutritional status, along with wounds and scars from ship strikes and fishing gear entanglement. Field application of these techniques has the potential to improve our understanding of the physiology of large whales greatly, better enabling assessment of the relative impacts of many anthropogenic and ecological pressures.