Growth rates of vibrissae of harbor seals (Phoca vitulina) and Steller sea lions (Eumetopias jubatus)

2001 ◽  
Vol 79 (6) ◽  
pp. 1053-1061 ◽  
Author(s):  
Amy C Hirons ◽  
Donald M Schell ◽  
David J St. Aubin
Keyword(s):  
Growth Rates ◽  
Isotope Analysis ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Harbor Seals ◽  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Active Growth ◽  
Sea Lions ◽  
Two Peaks

Growth rates of vibrissae (whiskers), which act as a temporal record of feeding in harbor seals (Phoca vitulina) and Steller sea lions (Eumetopias jubatus), were estimated using 13C- and 15N-labeled glycine followed by stable-isotope analysis. The labeled glycine was incorporated into keratin and served as a temporal marker for growth-rate calculation. One captive harbor seal received two doses 147 days apart, while a second seal received one dose; vibrissae were analyzed after 86 and 154 days. The peak positions indicated that growth began in the fall, continued into spring, but ceased in June, with active growth rates of 0.33 mm/day. Two adult captive Steller sea lions each received two labeled doses during a 308-day period. After 427 days vibrissae in both sea lions showed two peaks corresponding to the markers; growth rates were calculated as 0.05–0.07 mm/day. Growth rates in captive juvenile and wild adult Steller sea lions, 0.10–0.17 mm/day, supported the assumption that major isotopic oscillations in vibrissae of wild sea lions were annual. The multiyear records imply that Steller sea lions retain their vibrissae; harbor seal vibrissae, in contrast, have periods of rapid growth and appear to be shed, at least in part, annually.

Growth rates of vibrissae of harbor seals (Phoca vitulina) and Steller sea lions (Eumetopias jubatus)

2001 ◽  
Vol 79 (6) ◽  
pp. 1053-1061 ◽  
Author(s):  
Amy C. Hirons ◽  
Donald M. Schell ◽  
David J. St. Aubin
Keyword(s):  
Growth Rates ◽  
Phoca Vitulina ◽  
Harbor Seals ◽  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Sea Lions

scholarly journals Morphological characteristics of harbor seal (Phoca vitulina) whiskers and their use in dietary reconstruction using stable isotope ratios

2018 ◽  
Vol 96 (11) ◽  
pp. 1255-1263 ◽  
Author(s):  
Justin Smith ◽  
Shawna Karpovich ◽  
Greg A. Breed ◽  
Diane M. O’Brien
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Whisker Growth ◽  
Morphological Characteristics ◽  
Isotope Ratios ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Harbor Seals ◽  
Dietary Reconstruction ◽  
Whisker Morphology

We investigated whether inferences about harbor seal (Phoca vitulina Linnaeus, 1758) whisker shed status and growth rates based on whisker morphology could improve dietary time series from whisker isotopic profiles. We identified morphometric characteristics of Alaskan harbor seal whiskers, including a smooth root section (SRS) and a bumpy section. The SRS was longer for spring versus fall-collected whiskers and matched the length of fully grown, shed whiskers. Thus, SRS length can differentiate whisker shed and growth status, and we used it to determine the sequence of whisker shedding by cohort in summer-captured harbor seals. The mean interbump length (IBL) correlated with whisker length, potentially providing a proxy for whisker growth rate. We compared carbon isotope ratios (expressed as δ13C values) along the three longest whiskers from 10 harbor seals, using two approaches for converting whisker position to date: (1) a standard growth rate constant based on captive studies and (2) individually adjusted growth rates based on whisker morphology. Intraindividual patterns of whisker δ13C values became more synchronous when expressed by deposition date rather than by position; however, adjusting growth rates based on IBL did not improve synchrony further. These findings suggest that whisker morphology can contribute whisker growth rate and shedding information for dietary reconstruction.

scholarly journals Metagenomic identification of a novel anellovirus in Pacific harbor seal (Phoca vitulina richardsii) lung samples and its detection in samples from multiple years

2011 ◽  
Vol 92 (6) ◽  
pp. 1318-1323 ◽  
Author(s):  
Terry Fei Fan Ng ◽  
Elizabeth Wheeler ◽  
Denise Greig ◽  
Thomas B. Waltzek ◽  
Frances Gulland ◽  
...  
Keyword(s):  
Marine Mammals ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Viral Metagenomics ◽  
Harbor Seals ◽  
California Sea Lions ◽  
Viral Pathogens ◽  
Sea Lions ◽  
Mortality Event ◽  
Specific Pcr

To investigate viral pathogens potentially involved in a mortality event of 21 Pacific harbor seals (Phoca vitulina richardsii) in California in 2000, viral metagenomics was performed directly on lung samples from five individuals. Metagenomics revealed a novel seal anellovirus (SealAV), which clusters phylogenetically with anelloviruses from California sea lions and domestic cats. Using specific PCR, SealAV was identified in lung tissue from two of five animals involved in the 2000 mortality event, as well as one of 20 harbor seal samples examined post-mortem in 2008. The identification of SealAV in multiple years demonstrates that this virus is persistent in the harbor seal population. SealAV is the second anellovirus reported in the lungs of pinnipeds, suggesting that anellovirus infections may be common amongst marine mammals and that more research is needed to understand the roles of these viruses in marine mammal health and disease.

Diet composition of Steller sea lions (Eumetopias jubatus) in Frederick Sound, southeast Alaska: a comparison of quantification methods using scats to describe temporal and spatial variabilities

2015 ◽  
Vol 93 (5) ◽  
pp. 361-376 ◽  
Author(s):  
D.J. Tollit ◽  
M.A. Wong ◽  
A.W. Trites
Keyword(s):  
Pacific Salmon ◽  
Biomass Energy ◽  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Southeast Alaska ◽  
Merluccius Productus ◽  
Sea Lions ◽  
Sampling Protocols ◽  
Dietary Indices

We compared eight dietary indices used to describe the diet of Steller sea lions (Eumetopias jubatus (Schreber, 1776)) from 2001 to 2004 in Frederick Sound, southeast Alaska. Remains (n = 9666 items) from 59+ species categories were identified from 1684 fecal samples (scats) from 14 collection periods. The most frequently occurring prey were walleye pollock (Theragra chalcogramma (Pallas, 1814) = Gadus chalcogrammus Pallas, 1814; 95%), Pacific herring (Clupea pallasii Valenciennes in Cuvier and Valenciennes, 1847; 30%), Pacific hake (Merluccius productus (Ayres, 1855); 29%), and arrowtooth flounder (Atheresthes stomias (Jordan and Gilbert, 1880) = Reinhardtius stomias (Jordan and Gilbert, 1880); 21%). These species, along with Pacific salmon (genus Oncorhynchus Suckley, 1861) and skate (genus Raja L., 1758), accounted for 80%–90% of the reconstructed biomass and energy contribution, with pollock contributing 37%–60%. Overall, 80% of fish were 14–42 cm long and mainly pelagic, though 40% of scats contained benthic-associated prey. Steller sea lions switched from adult pollock to strong cohorts of juvenile pollock, and took advantage of spawning concentrations of salmon in autumn and herring in late spring and summer, as well as a climate-driven increase in hake availability. Observed temporal and site differences in diet confirm the need for robust long-term scat sampling protocols. All major indices similarly tracked key temporal changes, despite differences in occurrence and biomass-energy-based diet estimates linked to prey size and energy-density effects and the application of correction factors.

Maternal attendance patterns of Steller sea lions (Eumetopias jubatus) from stable and declining populations in Alaska

2003 ◽  
Vol 81 (2) ◽  
pp. 340-348 ◽  
Author(s):  
Linda L Milette ◽  
Andrew W Trites
Keyword(s):  
Prey Availability ◽  
A Priori ◽  
Population Decline ◽  
Perinatal Period ◽  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Sea Lions ◽  
First Feeding ◽  
Attendance Patterns ◽  
The Mean

Maternal attendance patterns of Alaskan Steller sea lions (Eumetopias jubatus) were compared during the summer breeding seasons in 1994 and 1995 at Sugarloaf Island (a declining population) and Lowrie Island (a stable population). Our goal was to determine whether there were differences in maternal attendance between the two populations that were consistent with the hypothesis that lactating Steller sea lions in the area of decline were food-limited during summer. Our a priori expectations were based on well-documented behavioural responses of otariids to reduced prey availability. We found that foraging trips were significantly shorter in the area of population decline, counter to initial predictions. The mean length of foraging trips in the declining area was 19.5 h compared with 24.9 h in the stable area. In contrast, the mean perinatal period (time between parturition and first feeding trip) was significantly longer in the area of decline (9.9 versus 7.9 days), again countering initial predictions. The mean length of shore visits for the declining population was also significantly longer (27.0 h compared with 22.6 h where the population was stable). For both populations, the mean time that mothers foraged increased as pups grew older, whereas the time that they spent on shore with their pups became shorter. Behavioural observations of maternal attendance patterns are inconsistent with the hypothesis that lactating Steller sea lions from the declining population had difficulty obtaining prey during summer.

High diving metabolism results in a short aerobic dive limit for Steller sea lions (Eumetopias jubatus)

2013 ◽  
Vol 183 (5) ◽  
pp. 699-708 ◽  
Author(s):  
Carling D. Gerlinsky ◽  
David A. S. Rosen ◽  
Andrew W. Trites
Keyword(s):  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Sea Lions ◽  
Aerobic Dive Limit
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