GROWTH AND DEVELOPMENT IN FREE‐RANGING HARBOR SEAL (PHOCA VITULINA) PUPS FROM SOUTHERN BRITISH COLUMBIA, CANADA

Abstract

Harbor seals (Phoca vitulina) are small pinnipeds that are widely distributed throughout the temperate coastal regions of the Atlantic and Pacific oceans. We determined birth mass, neonatal growth rates, weaning age, and weaning mass of NE Pacific harbor seals (P. v. richardsi) during a capture‐recapture study that spanned the nursing period (Sidney Island, British Columbia, Canada). Of 46 harbor seal pups initially captured, 28 were classified as newborns (i. e., < 24 h old). Mean body mass of newborns was 11.2 ± SE 0.31 kg. Pups were individually tagged and recaptured throughout the nursing period. Average daily mass gain during the nursing period was 394 ± 26 g. Mean birth mass of males did not differ significantly from females, although pups found with fetal pelage (lanugo) (21.4% of all newborns) were smaller at birth (9.8 ± 0.44 kg) than non‐lanugo pups (11.6 ± 0.33 kg). Mean weaning mass was estimated at 23.6 ± 1.2 kg at a mean weaning age of 32 d ± 1.5 d. While birth and weaning masses differed little from the published data for offshore Sable Island harbor seals (P. v. concolor), British Columbia harbor seals are characterized by half the daily mass gain and a longer nursing period.

Mercury Accumulation in Harbour Seals from the Northeastern Pacific Ocean: The Role of Transplacental Transfer, Lactation, Age and Location

“…Because weight can be used as a surrogate for age in harbour seal pups (Cottrell et al 2002), these results suggest an increase of THg in hair with age and therefore the duration of lactation in accordance to our whisker results described earlier. Similarly, the analysis of human hair from Faroe Island infants also suggested an increase of Hg with the nursing period (Grandjean et al 1995a).…”

BRUCELLA PINNIPEDIALISINFECTIONS IN PACIFIC HARBOR SEALS (PHOCA VITULINA RICHARDSI) FROM WASHINGTON STATE, USA

“…Using known pupping dates from a wellstudied harbor seal haul-out site (Gertrude Island, Washington) and weight/age correlations for harbor seals from British Columbia (Bigg, 1969, Cottrell et al, 2002, harbor seals were classified as pups (,2 mo), weaned pups (2-12 mo), yearlings (12-24 mo), subadults (24-48 mo), or adults (.48 mo).…”

Pathology and Epidemiology of Phocid Herpesvirus-1 in Wild and Rehabilitating Harbor Seals (Phoca vitulina richardsi) in the Northeastern Pacific

“…Of the 53 PhHV-1-positive animals for which data on age and sex were available, 46 (87%) were neonates (determined by presence of an umbilicus and/or lanugo coat, incomplete tooth eruption, and a body weight of ,25 kg) and 7 (13%) were weanlings (determined by time of year, complete tooth eruption, little or no umbilical remnant, and a body weight of ,35 kg) (Cottrell et al, 2002;Ronald and Gotts, 2003). Twenty-seven (51%) were females and 26 (49%) were males.…”

“…There was marked temporal clustering of cases, all of which occurred between July and October (with peak submissions in August). Although observer bias related to increased surveillance of seal haulout sites in the summer and fall may partially explain this result, it is more likely a reflection of the harbor seal pupping season in BC, Canada and Washington, USA, which takes place between June and September and is followed by weaning and breeding 4-6 wk later (Cottrell et al, 2002;Ronald and Gotts, 2003). During this period the greatest number of PhHV-1-susceptible seals (i.e., young of the year) are present within the population and adults are likely to be shedding virus, leading to increased PhHV-1 transmission and disease (Gulland et al, 1997;King et al, 2001).…”

“…), which can result in the introduction and subsequent transmission of the virus within these facilities. Cases of PhHV-1-associated disease in BC, Canada and Washington, USA appeared to occur later in the year than in California, USA, which is likely a result of geographic variation in the harbor seal pupping season (Gulland et al, 1997;King et al, 2001;Cottrell et al, 2002;Ronald and Gotts, 2003;Goldstein et al, 2004).…”