Pathology findings and correlation with body condition index in stranded killer whales (Orcinus orca) in the northeastern Pacific and Hawaii from 2004 to 2013
Open Access
- 2 December 2020
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLOS ONE
- Vol. 15 (12), e0242505
- https://doi.org/10.1371/journal.pone.0242505
Abstract
Understanding health and mortality in killer whales (Orcinus orca) is crucial for management and conservation actions. We reviewed pathology reports from 53 animals that stranded in the eastern Pacific Ocean and Hawaii between 2004 and 2013 and used data from 35 animals that stranded from 2001 to 2017 to assess association with morphometrics, blubber thickness, body condition and cause of death. Of the 53 cases, cause of death was determined for 22 (42%) and nine additional animals demonstrated findings of significant importance for population health. Causes of calf mortalities included infectious disease, nutritional, and congenital malformations. Mortalities in sub-adults were due to trauma, malnutrition, and infectious disease and in adults due to bacterial infections, emaciation and blunt force trauma. Death related to human interaction was found in every age class. Important incidental findings included concurrent sarcocystosis and toxoplasmosis, uterine leiomyoma, vertebral periosteal proliferations, cookiecutter shark (Isistius sp.) bite wounds, excessive tooth wear and an ingested fish hook. Blubber thickness increased significantly with body length (all p < 0.001). In contrast, there was no relationship between body length and an index of body condition (BCI). BCI was higher in animals that died from trauma. This study establishes a baseline for understanding health, nutritional status and causes of mortality in stranded killer whales. Given the evidence of direct human interactions on all age classes, in order to be most successful recovery efforts should address the threat of human interactions, especially for small endangered groups of killer whales that occur in close proximity to large human populations, interact with recreational and commercial fishers and transit established shipping lanes.This publication has 62 references indexed in Scilit:
- Distinguishing the Impacts of Inadequate Prey and Vessel Traffic on an Endangered Killer Whale (Orcinus orca) PopulationPLOS ONE, 2012
- West Nile Virus Infection in Killer Whale, Texas, USA, 2007Emerging Infectious Diseases, 2011
- Polyparasitism Is Associated with Increased Disease Severity in Toxoplasma gondii-Infected Marine Sentinel SpeciesPLoS Neglected Tropical Diseases, 2011
- Effects of age, sex and reproductive status on persistent organic pollutant concentrations in “Southern Resident” killer whalesMarine Pollution Bulletin, 2009
- Linking killer whale survival and prey abundance: food limitation in the oceans' apex predator?Biology Letters, 2009
- Killer whale (Orcinus orca) interactions with the tuna and swordfish longline fishery off southern and south-eastern Brazil: a comparison with shark interactionsJournal of the Marine Biological Association of the United Kingdom, 2007
- Propeller scars on and known home range of two orca(Orcinus orca)in New Zealand watersNew Zealand Journal of Marine and Freshwater Research, 1999
- Dietary specialization in two sympatric populations of killer whales (Orcinus orca) in coastal British Columbia and adjacent watersCanadian Journal of Zoology, 1998
- Isolation of St. Louis encephalitis virus from a killer whaleClinical and Diagnostic Virology, 1993
- PRESENCE OF SOLID FOOD IN A YOUNG CALF KILLER WHALE (ORCINUS ORCA)Marine Mammal Science, 1988