Serum biochemistry and haematology in wild and captive bearded seals (Erignathus barbatus) from Svalbard, Norway

Morten Tryland,Kit Maureen Kovacs,Stein Istre Thoresen,Espen Rafter,Christian Lydersen

doi:10.1186/s13028-021-00598-8

Abstract

BackgroundHealth assessment of seals in captivity include haematology and serum biochemistry measurements. Because such parameters differ between species, it is crucial to have species-specific reference values for the interpretation of clinical samples. Furthermore, differences in nutrition and environment, life cycles as well as seasonal/annual cycles and varying physiological conditions can potentially affect serum chemistry and haematology parameters. Blood samples from four captive adult bearded seals (initially caught as pups in Svalbard, Norway, now held at Polaria, an Arctic experience centre in Tromsø, Norway) collected over a 16-month period were analysed for haematology (n = 22) and serum chemistry (n = 25) parameters. Serum chemistry analyses were also conducted on blood samples from 74 wild bearded seals (1995–2007) collected from Svalbard, Norway.ResultsWe found higher activity of creatine kinase (CK) and higher concentrations of cortisol in the wild animals when compared to the captive seals, probably reflecting the physical restraint and concomitant stress induced during sampling. For the captive bearded seals, we did not find marked differences in haematology or serum chemistry parameters throughout the different seasons of sampling.ConclusionsThis study presents haematology and serum chemistry reference values for captive and wild bearded seals. Comparing physiological parameters for captive seals with wild seals indicated that having wild-caught bearded seals under the conditions offered at Polaria for several years did not markedly affect physiological parameters of the animals, and that training may have helped to alleviate stress associated with blood sampling and veterinary inspection.

Highlights

Health assessment of seals in captivity include haematology and serum biochemistry measurements
From the wild bearded seals, 36 samples were classified by the ADVIA system as being slightly lipaemic (1+) and 28 were classified as moderately lipaemic (2+)
When comparing results from samples with no or slight lipaemia (1+) to samples with moderate lipaemia (2+), we found no obvious differences for parameters previously reported for marine mammal sera that might potentially be affected by moderate lipaemia, such as creatine kinase (CK), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), lipase, urea, creatinine, sodium and chloride [18]

Summary

Introduction

Health assessment of seals in captivity include haematology and serum biochemistry measurements Because such parameters differ between species, it is crucial to have species-specific reference values for the interpretation of clinical samples. Blood samples from four captive adult bearded seals (initially caught as pups in Svalbard, Norway, held at Polaria, an Arctic experience centre in Tromsø, Norway) collected over a 16-month period were analysed for haematology (n = 22) and serum chemistry (n = 25) parameters. Serum chemistry analyses were conducted on blood samples from 74 wild bearded seals (1995–2007) collected from Svalbard, Norway. The bearded seal (Erignathus barbatus) is the largest northern phocid seal This species is distributed, at low densities, throughout the circumpolar Arctic. Bearded seals are found at low densities in the fjords of Svalbard, Norway They are predominantly benthic feeders, eating clams, shrimp, squid, crabs and fish. Bearded seals have a longevity of 20–25 years in the wild [1]

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