 Austen Thomas has just returned from his first field season visiting local harbor seal haulouts as part of larger study on the diet of this species in the Strait of Georgia. Austen and his team of volunteers surveyed potential sites to collect harbor seal scats for a large scale study planned for 2012-2013. They also collected scats from wild harbor seals to validate the use of prey DNA in harbor seal fecal remains to quantify prey consumed. Scats were collected during the late summer/early fall salmon migration into the Fraser River, allowing Austen to compare salmon consumption by harbor seals in two very different habitat types using DNA analyses. This Fraser River collection constitutes the largest sample size of harbor seal scats ever collected during the adult salmon migration.
Austen and his local harbor seal scats will soon be making a long-distance trip together. They will travel to the Australian Antarctic Division Laboratory in Hobart, Tasmania, where Austen will learn how to identify prey from genetic analysis of scat. Austen will work with Dr. Bruce Deagle and Dr. Simon Jarmon — two Australian researchers who are among the world’s foremost molecular ecologists.
Results from this study will reveal how much and what species of salmon are consumed by harbor seals throughout the Strait of Georgia during the fall migration and other key times of year.
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 Tiphaine Jeanniard du Dot is investigating how the foraging efficiency of northern and Antarctic fur seals affects pup growth and, ultimately, population trends. Her field work aims to determine how much energy lactating females spend foraging relative to their success at capturing prey, and how this relates to the energy they can provide to their pups.
This summer, Tiphaine and her team of biologists and a veterinarian went to St. Paul Island, Alaska in the Bering Sea to study northern fur seals. They captured 20 mother-pup pairs and equipped the females with several high-tech gadgets to record their at-sea behaviors. These included a GPS logger to know where they went to forage, and a “daily diary” tag that recorded fine-scale, three-dimensional movement in the water column, and a fine scale accelerometer on their head to detect prey capture attempts. The females were also injected with doubly-labeled water to determine energy expenditure during each foraging trip. Finally, they collected data on the growth of male and female pups on shore and collected scats on the rookery for diet analysis.
The female fur seals tracked went on foraging trips that lasted from 5 to 14 days and traveled between 250 to 800 km to and from their foraging grounds. Females on the same rookery did not forage in the same areas, but dispersed in all directions around the island, with some staying on the continental shelf and others foraging in deep waters.
Ultimately, the data collected will help scientists understand the foraging efficiency of different foraging strategies and how this translates into pup growth. This will contribute to understanding whether the decline of the Pribilof population is related to difficulties capturing prey.
Unfortunately, Tiphaine doesn’t have the luxury of sitting at a desk right now to analyze all of her data. She is already busy preparing to perform similar measurements on Antarctic fur seals. This field season in Antarctic waters is scheduled for the 2011-2012 breeding season from December to April.
Austen Thomas and Tiphaine Jeanniard du Dot are both Ph.D students at U.B.C.
Tiphaine’s research on fur seals in Alaska is supported by the North Pacific Research Board, and Austen’s research on harbor seal predation is supported by the Pacific Salmon Foundation. Fur seal photograph taken under NMFS Research Permit Number 14329.
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