Comparative Health Assessments of Alaskan Ice Seals

Caroline E. C. Goertz,Peter Boveng,Heather Ziel,Colleen Reichmuth,Nicole M. Thometz

doi:10.3389/fvets.2019.00004

Abstract

Bearded (Erignathus barbatus), ringed (Pusa hispida), spotted (Phoca largha), and ribbon (Histriophoca fasciata) seals rely on seasonal sea-ice in Arctic and sub-Arctic regions. Many aspects of the biology and physiology of these seals are poorly known, and species-typical health parameters are not available for all species. Such information has proven difficult to obtain due to the challenges of studying Arctic seals in the wild and their minimal historic representation in aquaria. Here, we combine diagnostic information gathered between 2000 and 2017 from free-ranging seals, seals in short-term rehabilitation, and seals living in long-term human care to evaluate and compare key health parameters. For individuals in apparent good health, hematology, and blood chemistry values are reported by the source group for 10 bearded, 13 ringed, 73 spotted, and 81 ribbon seals from Alaskan waters. For a smaller set of individuals handled during veterinary or necropsy procedures, the presence of parasites and pathogens is described, as well as exposure to a variety of infectious diseases known to affect marine mammals and/or humans, with positive titers observed for Brucella, Leptospira, avian influenza, herpesvirus PhHV-1, and morbillivirus. These data provide initial baseline parameters for hematology, serum chemistries, and other species-level indicators of health that can be used to assess the condition of individual seals, inform monitoring and management efforts, and guide directed research efforts for Alaskan populations of ice-associated seals.

Highlights

Rapid environmental change threatens the stability and overall health of Arctic and subArctic ecosystems [1,2,3]
The information presented here provides a set of initial baseline parameters and observations for Alaskan ice seals that may be considered in the context of emerging conservation concerns for Arctic environments, including those related to climate change and associated sea ice loss, increasing risks of contamination from oil, hazardous materials, and pollutants, introduction of pathogenic vectors including parasites and viruses, and food safety issues for subsistence communities
When compared to other Arctic seals, the Alaskan ice seals exhibited higher Red blood cell (RBC) counts than both harp and hooded seals, and higher Hct values than harp seals [61, 62]

Summary

Introduction

Rapid environmental change threatens the stability and overall health of Arctic and subArctic ecosystems [1,2,3]. The transboundary nature of this UME increases concern that the opening of northwest and northeast passages through the Arctic, created by retreating sea ice, may result in disease transmission and possible epidemics in Alaskan marine mammals [see [10]]. This concern appears to be well founded, as nucleic acids from, and antibodies to, phocine distemper virus (PDV)—a pathogen responsible for two epidemics in northern Europe—have been detected for the first time in the North Pacific Ocean within the last decade [11], coincident with the first seasonal icefree access routes through the Arctic from the North Atlantic Ocean [12]

Methods

Results

Discussion

Conclusion