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| From the fort overlooking the city |
Nice and cool in Halifax and a very nice city. This is my first marine mammal conference, a needed perspective in the context of my research. Working in a chemistry laboratory in a geology department with a isotope biogeochemist as my adviser and zooarchaeologists as my collaborators I don't often get a chance to speak with people who work directly with animals.
There's been a number of great talks and I'd like to highlight some of them below:
The California sea lion: Isotopic indicator of changing conditions in the Gulf of California, Mexico presented by Julieta Sandoval-Sierra
Julieta's analysis was very similar to my own project, modeling food webs using carbon and nitrogen stable isotopes but with a very different application. Instead of comparing data over vast time periods, she showed a gradient in niche width from north to south in Baja California due to variation in oceanographic characteristics. Sea lions were eating very differently throughout this range.
Pre-historic insights into northern fur seals and fishing territories in the Pacific Northwest presented by Andrew W. Trites
Andrew told an amazing story of how science can be applied for social justice. An 1856 treaty granted fishing rights to several Native American tribes on the Washington coast, and a dispute over the boundaries of those fishing grounds was in the courts. Andrew used historical documents and isotopic analysis of archaeological materials to show that indigenous peoples were hunting a population of fur seals that existed off the continental shelf break (but no longer does today), far from shore at the time the treaty was made. After 30 years of losing in the courts, the judge was convinced by Andrew's testimony and awarded these tribes rights to fish all the way to the continental shelf break.
Eating seal or hungry like a wolf? Polar bear use of terrestrial resources revealed by compound-specific stable isotopes presented by Lara Horstmann
Lara applied isotopic analyses of amino acids to show how polar bears are beginning to rely more and more on terrestrial foods, such as elk and berries, instead of their preferred food, ringed seals. This appears to be directly related to loss of sea ice in the arctic, as polar bears will hunt these seals on the ice. One population of polar bears appears to be entirely terrestrial at this point, in direct competition with brown bear in north Alaska. She also measured cortisol in bone as an indicator of acute stress response, though didn't find much. An interesting idea though!
