Causes of mortality of harbor porpoises Phocoena phocoena along the Atlantic and Pacific coasts of Canada.

There is increasing public interest in the overall health of the marine environment. Harbor porpoises Phocoena phocoena have a coastal distribution, and stranded animals function as sentinels for population and ecosystem health. The goal of this retrospective study was to join datasets from the western Atlantic and eastern Pacific coasts of Canada to investigate causes of morbidity and mortality in this species. A total of 241 necropsy records were reviewed including 147 (61%) from the Pacific region and 94 (39%) from the Atlantic region from 1988 to 2011. A cause of death could be determined with confidence in 118 (49%) of these cases. Of these 118 cases, the leading cause of mortality for both regions, together and separately, was infectious disease. In the Pacific region, this was followed by traumatic and anthropogenic causes, whereas in the Atlantic region, it was followed by emaciation/starvation, mortality of dependent calves, and anthropogenic causes. Pathogens of potential zoonotic significance or indicative of environmental contamination, e.g. Salmonella sp. and Cryptococcus gattii, were identified. Numerous parasitic species were observed within the lungs, liver, stomach, middle ear, and subcutaneous tissues, although they were usually interpreted as incidental findings. Anthropogenic causes may be underrepresented as they are notoriously difficult to diagnose with certainty, thereby making up a proportion of the 'unknown causes of death' (51%) category. Improved standardization of data collection and documentation is required to better understand harbor porpoise and ecosystem health.

[1]  D. Martineau,et al.  Pathologic Findings and Trends in Mortality in the Beluga (Delphinapterus leucas) Population of the St Lawrence Estuary, Quebec, Canada, From 1983 to 2012 , 2016, Veterinary pathology.

[2]  J. Reif,et al.  Atlantic Bottlenose Dolphins (Tursiops truncatus) as A Sentinel for Exposure to Mercury in Humans: Closing the Loop , 2015, Veterinary sciences.

[3]  A. Sweeny,et al.  A novel Sarcocystis neurona genotype XIII is associated with severe encephalitis in an unexpectedly broad range of marine mammals from the northeastern Pacific Ocean. , 2015, International journal for parasitology.

[4]  L. Barre,et al.  Increased harbor porpoise mortality in the Pacific Northwest, USA: understanding when higher levels may be normal. , 2015, Diseases of aquatic organisms.

[5]  M. Leopold,et al.  Porpoises: From predators to prey , 2015 .

[6]  S. Raverty,et al.  CLINICAL AND EPIDEMIOLOGIC CONSIDERATIONS OF CLOSTRIDIUM DIFFICILE IN HARBOR SEALS (PHOCA VITULINA) AT A MARINE MAMMAL REHABILITATION CENTER , 2015 .

[7]  M. Moore,et al.  Body Condition Scoring System for Delphinids Based on Short-beaked Common Dolphins ( Delphinus delphis ) , 2015 .

[8]  U. Siebert,et al.  Phocine Distemper Virus: Current Knowledge and Future Directions , 2014, Viruses.

[9]  Oceans Canada,et al.  Phycotoxin analyses in St. Lawrence Estuary beluga , 2014 .

[10]  D. Rotstein,et al.  Unusual Mortality Events of Harbor Porpoise Strandings in North Carolina, 1997–2009 , 2013 .

[11]  P. Jepson,et al.  Pathology and causes of death of stranded cetaceans in the Canary Islands (1999-2005). , 2013, Diseases of aquatic organisms.

[12]  J. Teilmann,et al.  Possible Causes of a Harbour Porpoise Mass Stranding in Danish Waters in 2005 , 2013, PloS one.

[13]  Julie M Van Der Hoop,et al.  Assessment of Management to Mitigate Anthropogenic Effects on Large Whales , 2012, Conservation biology : the journal of the Society for Conservation Biology.

[14]  G. Guardo.  Morbillivirus-host interaction: lessons from aquatic mammals , 2012, Front. Microbio..

[15]  S. Wasser,et al.  Evidence that ship noise increases stress in right whales , 2012, Proceedings of the Royal Society B: Biological Sciences.

[16]  S. Larrat.  Short Note: Rake Marks on a Harbor Porpoise (Phocoena phocoena) Calf Suggestive of a Fatal Interaction with an Atlantic White-Sided Dolphin (Lagenorhynchus acutus) , 2012 .

[17]  J. Haelters.  Short Note: Two Cases of Physical Interaction Between White-Beaked Dolphins (Lagenorhynchus albirostris) and Juvenile Harbour Porpoises (Phocoena phocoena) in the Southern North Sea , 2011 .

[18]  D. Lusseau,et al.  Underestimating the damage: interpreting cetacean carcass recoveries in the context of the Deepwater Horizon/BP incident , 2011 .

[19]  S. Raverty,et al.  Polyparasitism Is Associated with Increased Disease Severity in Toxoplasma gondii-Infected Marine Sentinel Species , 2011, PLoS neglected tropical diseases.

[20]  Eric S. Zolman,et al.  Bottlenose dolphins as indicators of persistent organic pollutants in the western North Atlantic Ocean and northern Gulf of Mexico. , 2011, Environmental science & technology.

[21]  W. Van Bonn,et al.  Antemortem diagnosis of a ventricular septal defect in a California sea lion Zalophus californianus. , 2011, Diseases of aquatic organisms.

[22]  G. Ylitalo,et al.  Congenital Neuroglial Heterotopia in a Neonatal Harbor Seal (Phoca vitulina richardsi ) with Evidence of Recent Exposure to Polycyclic Aromatic Hydrocarbons , 2011, Journal of wildlife diseases.

[23]  M. Moore,et al.  Mortality trends of stranded marine mammals on Cape Cod and southeastern Massachusetts, USA, 2000 to 2006. , 2010, Diseases of aquatic organisms.

[24]  D. Mcalpine,et al.  Cetacean Strandings in the Canadian Maritime Provinces, 1990-2008 , 2010 .

[25]  J. Raga,et al.  Emerging infectious diseases in cetaceans worldwide and the possible role of environmental stressors. , 2009, Diseases of aquatic organisms.

[26]  T. Lipscomb,et al.  MAJOR PATHOLOGIC FINDINGS AND PROBABLE CAUSES OF MORTALITY IN BOTTLENOSE DOLPHINS STRANDED IN SOUTH CAROLINA FROM 1993 TO 2006 , 2009, Journal of wildlife diseases.

[27]  S. Bilgin,et al.  The Effect of Pingers on Harbour Porpoise, Phocoena phocoena Bycatch and Fishing Effort in the Turbot Gill Net Fishery in the Turkish Black Sea Coast , 2009 .

[28]  S. Ridgway,et al.  Neuronal Migration Defect: A Case of Subcortical Heterotopia in a California Sea Lion , 2008, Veterinary pathology.

[29]  L. Measures.  Lungworms of Marine Mammals , 2008 .

[30]  J. Prescott,et al.  Chapter 13. Salmonellosis , 2008 .

[31]  C. Camphuysen,et al.  Cetaceans stranded in the Netherlands from 1998 to 2007 , 2008 .

[32]  P. Wade,et al.  Worldwide Distribution and Abundance of Killer Whales , 2007 .

[33]  G. Bossard.  Marine Mammals as Sentinel Species for Oceans and Human Health , 2006 .

[34]  Simon Northridge,et al.  Bycatch of Marine Mammals in U.S. and Global Fisheries , 2006, Conservation biology : the journal of the Society for Conservation Biology.

[35]  C. Stephen,et al.  Cryptococcus gattii in Wildlife of Vancouver Island, British Columbia, Canada , 2006, Journal of wildlife diseases.

[36]  J. R. Baker,et al.  Relationships between polychlorinated biphenyls and health status in harbor porpoises (Phocoena phocoena) stranded in the United Kingdom , 2005, Environmental toxicology and chemistry.

[37]  K. Lafferty,et al.  ARE DISEASES INCREASING IN THE OCEAN , 2004 .

[38]  S. A. Norman.  Multidisciplinary investigation of stranded harbor porpoises (Phocoena phocoena) in Washington State with an assessment of acoustic trauma as a contributory factor (2 May-2 June 2003) , 2004 .

[39]  J. Haelters,et al.  Post-mortem findings and causes of death of harbour porpoises (Phocoena phocoena) stranded from 1990 to 2000 along the coastlines of Belgium and Northern France. , 2002, Journal of comparative pathology.

[40]  Karen Birmingham,et al.  the heart , 2002, Nature.

[41]  P. Quinn.  Veterinary Microbiology and Microbial Disease , 2001 .

[42]  P. Corkeron,et al.  Boat traffic affects the acoustic behaviour of Pacific humpback dolphins, Sousa chinensis , 2001, Journal of the Marine Biological Association of the United Kingdom.

[43]  U. Siebert,et al.  Post-mortem findings in harbour porpoises (Phocoena phocoena) from the German North and Baltic Seas. , 2001, Journal of comparative pathology.

[44]  D. W. Laist,et al.  COLLISIONS BETWEEN SHIPS AND WHALES , 2001 .

[45]  T. Kuiken,et al.  Exposure to heavy metals and infectious disease mortality in harbour porpoises from England and Wales. , 2001, Environmental pollution.

[46]  T. Kuiken,et al.  Pulmonary pathology of harbour porpoises (Phocoena phocoena) stranded in England and Wales between 1990 and 1996 , 2000, Veterinary Record.

[47]  C. Gili,et al.  Histopathological and immunohistochemical studies on cetaceans found stranded on the coast of Italy between 1990 and 1997. , 2000, Journal of veterinary medicine. A, Physiology, pathology, clinical medicine.

[48]  T. Jefferson,et al.  POST-MORTEM INVESTIGATIONS ON STRANDED DOLPHINS AND PORPOISES FROM HONG KONG WATERS , 2000, Journal of wildlife diseases.

[49]  G. Stone,et al.  Hector's Dolphin 'Cephalorhynchus hectori' Calf Mortalities May Indicate New Risks from Boat Traffic and Habituation , 2000 .

[50]  John M. Terhune,et al.  Mitigation of harbour porpoise (Phocoena phocoena) by-catch in the gillnet fishery in the lower Bay of Fundy , 1999 .

[51]  P. Jepson,et al.  FURTHER INSIGHT ON THE EPIDEMIOLOGY OF CETACEAN MORBILLIVIRUS IN THE NORTHEASTERN ATLANTIC , 1998 .

[52]  H. Koopman.  Topographical Distribution of the Blubber of Harbor Porpoises (Phocoena phocoena) , 1998 .

[53]  R. Baird.  An interaction between Pacific white-sided dolphins and a neonatal harbor porpoise , 1998 .

[54]  M. Kingsley,et al.  Concentrations and accumulation patterns of organochlorine contaminants in the blubber of harbour porpoises, Phocoena phocoena, from the coast of Newfoundland, the Gulf of St Lawrence and the Bay of Fundy/Gulf of Maine. , 1997, Environmental pollution.

[55]  E. Trippel,et al.  Incidental mortality of harbour porpoise (Phocoena phocoena) by the gill-net fishery in the lower Bay of Fundy , 1996 .

[56]  D. Muir,et al.  Persistent organochlorines in beluga whales (Delphinapterus leucas) from the St Lawrence River estuary--II. Temporal trends, 1982-1994. , 1996, Environmental pollution.

[57]  J. Baker,et al.  Causes of mortality and parasites and incidental lesions in harbour porpoises (Phocoena phocoena) from British waters , 1992, Veterinary Record.

[58]  P. Boveng,et al.  MODELING AGE‐SPECIFIC MORTALITY FOR MARINE MAMMAL POPULATIONS , 1991 .

[59]  A. Read.  Estimation of body condition in harbour porpoises, Phocoena phocoena , 1990 .

[60]  D. Anderson,et al.  Humpback Whales (Megaptera novaeangliae) Fatally Poisoned by Dinoflagellate Toxin , 1989 .

[61]  J. Naylor,et al.  Protein energy malnutrition and fat mobilization in neonatal calves. , 1986, The Canadian veterinary journal = La revue veterinaire canadienne.

[62]  R. Mitchell.  Environmental quality. , 1981, Science.

[63]  S. G. Brown.  Relation Between Stranding Mortality and Population Abundance of Smaller Cetacea in the Northeast Atlantic Ocean , 1975 .

[64]  H. Mersmann.  Metabolic patterns in the neonatal swine. , 1974, Journal of animal science.

[65]  R. Conklin,et al.  MULTIPLE BIRTHS AND CARDIAC ANOMALIES IN THE BOTTLE-NOSED DOLPHIN1 , 1974, Journal of wildlife diseases.

[66]  P. Arnold.  Predation on Harbour Porpoise, Phocoena phocoena, by a White Shark, Carcharodon carcharias , 1972 .

[67]  金潤,et al.  SALMONELLOSIS , 1974 .