Averaged Propulsive Body Acceleration (APBA) Can Be Calculated from Biologging Tags That Incorporate Gyroscopes and Accelerometers to Estimate Swimming Speed, Hydrodynamic Drag and Energy Expenditure for Steller Sea Lions

Drag forces acting on Steller sea lions (Eumetopias jubatus) were investigated from ‘deceleration during glide’ measurements. A total of 66 glides from six juvenile sea lions yielded a mean drag coefficient (referenced to total wetted surface area) of 0.0056 at a mean Reynolds number of 5.5×10(6). The drag values indicate that the boundary layer is largely turbulent for Steller sea lions swimming at these Reynolds numbers, which are past the point of expected transition from laminar to turbulent flow. The position of maximum thickness (at 34 % of the body length measured from the tip of the nose) was more anterior than for a ‘laminar’ profile, supporting the idea that there is little laminar flow. The Steller sea lions in our study were characterized by a mean fineness ratio of 5.55. Their streamlined shape helps to delay flow separation, reducing total drag. In addition, turbulent boundary layers are more stable than laminar ones. Thus, separation should occur further back on the animal. Steller sea lions are the largest of the otariids and swam faster than the smaller California sea lions (Zalophus californianus). The mean glide velocity of the individual Steller sea lions ranged from 2.9 to 3.4 m s(−)(1) or 1.2-1.5 body lengths s(−)(1). These length-specific speeds are close to the optimum swim velocity of 1.4 body lengths s(−)(1) based on the minimum cost of transport for California sea lions.

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Validating the relationship between 3-dimensional body acceleration and oxygen consumption in trained Steller sea lions

Journal of Comparative Physiology B ◽

10.1007/s00360-015-0911-y ◽

2015 ◽

Vol 185 (6) ◽

pp. 695-708 ◽

Cited By ~ 10

Author(s):

Beth L. Volpov ◽

David A. S. Rosen ◽

Andrew W. Trites ◽

John P. Y. Arnould

Keyword(s):

Oxygen Consumption ◽

Steller Sea Lions ◽

Body Acceleration ◽

3 Dimensional ◽

Sea Lions ◽

The Relationship

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MULTIPLE HYPOTHESIS TESTING AND THE DECLINING-POPULATION PARADIGM IN STELLER SEA LIONS

Ecological Applications ◽

10.1890/07-1254.1 ◽

2008 ◽

Vol 18 (8) ◽

pp. 1932-1955 ◽

Cited By ~ 22

Author(s):

Nicholas Wolf ◽

Marc Mangel

Keyword(s):

Hypothesis Testing ◽

Multiple Hypothesis Testing ◽

Steller Sea Lions ◽

Sea Lions ◽

Multiple Hypothesis

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Evidence of partial deferment of digestion during diving in Steller sea lions (Eumetopias jubatus)

Journal of Experimental Marine Biology and Ecology ◽

10.1016/j.jembe.2015.04.017 ◽

2015 ◽

Vol 469 ◽

pp. 93-97 ◽

Cited By ~ 10

Author(s):

David A.S. Rosen ◽

Carling D. Gerlinsky ◽

Andrew W. Trites

Keyword(s):

Eumetopias Jubatus ◽

Steller Sea Lions ◽

Sea Lions

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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

Canadian Journal of Zoology ◽

10.1139/cjz-2014-0292 ◽

2015 ◽

Vol 93 (5) ◽

pp. 361-376 ◽

Cited By ~ 7

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.

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

Canadian Journal of Zoology ◽

10.1139/z03-008 ◽

2003 ◽

Vol 81 (2) ◽

pp. 340-348 ◽

Cited By ~ 35

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.

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