title: Pathology and Epidemiology of Stillbirth in New Zealand Sea Lions (Phocarctos hookeri) From Enderby Island, Auckland Islands, 1998-2012.
abstract: Stillbirth is a small and often cryptic fraction of neonatal mortality in mammals including pinnipeds. As part of an investigation into the poor reproductive success of the endangered New Zealand sea lion (Phocarctos hookeri), archived tissues from 37 stillborn pups born on Enderby Island between 1998 and 2012 were examined using histopathological techniques. Apart from bronchopneumonia with neutrophilic infiltration in 4 cases, few inflammatory conditions were identified in stillborn pups. However, 27/32 (84%) stillborn pups had aspirated squames present in the respiratory tract, without meconium. It is unclear if this finding represents fetal distress during parturition or whether it is a normal finding for this species. Three pups lacked histological evidence of hepatic glycogen storage, which may indicate placental defects or maternal undernutrition. No evidence of infectious disease was found on histopathological analysis, consistent with the low seroprevalence in New Zealand of infections known to cause reproductive failure in other pinniped species. This study forms an important baseline for further examination of stillborn New Zealand sea lion pups, as pup mortality is investigated as a contributor to the species' decline.
authors.affiliation: Wildbase, Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand sarah.a.michael@gmail.com.
authors.forename: S A
authors.initials: SA
authors.lastname: Michael
authors.affiliation: Marine Species and Threats, Department of Conservation, Wellington, New Zealand Current address: Wildbase, Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand.
authors.forename: B L
authors.initials: BL
authors.lastname: Chilvers
authors.affiliation: Wildbase, Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand.
authors.forename: S A
authors.initials: SA
authors.lastname: Hunter
authors.affiliation: Department of Ecosystem and Public Health, University of Calgary, Calgary, Alberta, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Duignan
authors.affiliation: Pathobiology Group, Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand.
authors.forename: W
authors.initials: W
authors.lastname: Roe
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D056727:Endangered Species; D005260:Female; D005333:Fetus / Q000473:pathology; D008297:Male; D009520:New Zealand / Q000453:epidemiology; D046070:Sea Lions; D050497:Stillbirth / Q000453:epidemiology / Q000662:veterinary*
keywords: aspiration pneumonia; fetal distress; liver glycogen; pinnipedia; squamous cells; stillbirth