Drift-block experiments to analyse the mortality of oiled seabirds off Vancouver Island, British Columbia
Hlady, D.A.; Burger, A.E. (1993). Drift-block experiments to analyse the mortality of oiled seabirds off Vancouver Island, British Columbia. Mar. Biol. (Berl.) 26(9): 495-501
In: Marine Biology: International Journal on Life in Oceans and Coastal Waters. Springer: Heidelberg; Berlin. ISSN 0025-3162; e-ISSN 1432-1793, more
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Keywords |
Accidents > Oil spills Aquatic organisms > Marine organisms > Aquatic birds > Marine birds Carcasses Drift Environments > Aquatic environment > Marine environment Pollution > Oil pollution Pollution > Water pollution > Marine pollution Population functions > Mortality Stranding Water pollution effects Aves [WoRMS] INE, Canada, British Columbia, Vancouver I., Barkl [Marine Regions] Marine/Coastal |
Abstract |
The authors used wooden drift-blocks, simulating carcasses, to estimate the proportion of oiled seabirds which might come ashore following an oil spill off Vancouver Island, British Columbia, Canada. Blocks were released at an inshore site (1-2 km offshore), and at four offshore sites (35-116 km offshore). In the month following releases, we recovered 43% and 53% of the inshore blocks in summer and winter, respectively, but only 10% of the offshore releases in the winter. Most blocks were found within 10 km of the release sites, but a few travelled >400 km. Recovery rates of inshore blocks were not strongly affected by tidal flow, whereas wind and the Vancouver Island Coastal Current had significant effects. Block size had little effect on recovery or distance travelled. Fewer blocks were recovered from rocky shores and more from sand and gravel beaches than expected, and many blocks were mixed among logs and kelp jetsam. These data indicate that seabird mortality following marine oil spills could be greatly underestimated, particularly if the spills occurred far offshore |
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