Search Results

May

14

2007
 
 

I am (glad I’m not) the walrus



Novel biomarkers reveal what polar bears do and don’t eat feel like walrus tonight?Polar bears are -- like humans -- what they eat, a fact put to good use by scientists studying the dietary requirements of the embattled Arctic carnivores. Writing in the Canadian Journal of Zoology, a team of zoologists led by the University of Alberta’s Gregory Thiemann describe how certain fatty acids in tissue samples obtained from polar bears Ursus maritimus hint at their predatory habits. The chemical signature of the samples allowed the scientists to track the bears’ food right to the bottom of the food chain -- the particular fatty acids were known to be produced by mollusks on the sea floor, which are only eaten by certain prey species (bearded seals Erignathus barbatus and Atlantic walruses Odobenus rosmarus). The Arctic’s alarming ecological shifts, largely in response to climate change, have the capacity to profoundly affect its wildlife. Being able to monitor who’s eating who offers a tiny ray of hope that we might soon understand enough to limit the damage. Source: Thiemann GW, Budge SM, Iverson SJ & Stirling I (2007) Unusual fatty acid biomarkers reveal age- and sex-specific foraging in polar bears (Ursus maritimus). Canadian Journal of Zoology DOI: 10.1139/Z07-028 Image © Gail Johnson

Filed Under Climate change, Endangered species, Marine, Monitoring, Tools and technology | Leave a Comment

Email This Post Email This Post

Mar

30

2007
 
 

Lean, green, killing machine



fly the gauntlet!Wind turbines are getting more bird-friendly, but bats are still suffering Wind turbines kill bats as well as birds, according to a recent report in the Canadian Journal of Zoology. The University of Calgary study, led by Robert Barclay, found a sharp rise in the number of bat fatalities linked with increasing height of turbine towers: the technological trend has been towards fewer, taller structures. One possible cause of the flying mammals’ demise, say the study’s authors, is that the speed of the whirling rotor – some 200 km/h at the tips of the largest blades – is simply too fast for them to avoid. Although changes in turbine design, placement and lighting have probably resulted in fewer bird fatalities, nothing is currently being done to save bats from the chop. Source: Barclay RMR, Baerwald EF & Gruver JC (2007) Variation in bat and bird fatalities at wind energy facilities: assessing the effects of rotor size and tower height. Canadian Journal of Zoology DOI: 10.1139/Z07-011 Image © Maxfx Related story in Conservation magazine: Getting it right the first time

Filed Under Climate change, Monitoring, Socio-political issues, Tools and technology | Leave a Comment

Email This Post Email This Post

Feb

4

2007
 
 

Squid marks



Steller sealion (open wide!)Experiment shows how to estimate wild sea mammal diets Rummaging through mounds of sealion poo might not be everyone’s dream vocation, but for Dom Tollit and colleagues at the Marine Mammal Research Unit, University of British Columbia, it provides a means to an end... so to speak. Testing (and no doubt hoping to uphold) the old adage of “what goes in, must come out”, they conducted a series of feeding trials on captive Steller sealions and report their findings this week. By searching for fish otoliths, bones and squid beaks, they were able to develop a method for back-calculating what a sealion ate, given its faeces. This should help conservationists to find out what’s been on the menu for sealions and other pinnipeds in the field. Source: Tollit, DJ, Heaslip, SG, Barrick, RL & Trites, AW (2007) Impact of diet-index selection and the digestion of prey hard remains on determining the diet of the Steller sea lion (Eumetopias jubatus). Canadian Journal of Zoology DOI: 10.1139/Z06-174

Filed Under Marine, Monitoring | 1 Comment

Email This Post Email This Post