> A new paper is now available: > Sumich, J.L., and Show, I.T. 2011. Offshore migratory morridors and aerial > photogrammetric body length comparisons of southbound gray whales, > Eschrichtius robustus, in the southern California Bight, 1988-1990. Marine > Fisheries Review 73: 28-34. > > Abstract: > Through most of their annual migration, gray whales, Eschrichtius robustus, > remain within 10 km of shore, but in the Southern California Bight many > individuals migrate much farther from shore. This paper summarizes aerial > survey and photogrammetric efforts to determine body lengths and temporal and > spatial distributions of migratory gray whales in the southern portion of the > Southern California Bight. Aerial surveys were flown along 13 east–west > transects between lat. 32°35′N and 33°30′N during the southbound gray whale > migratory seasons of 1988–90 in the Southern California Bight. Photogrammetry > was used to obtain body length estimates of animals during some of the > surveys. A total of 1,878 whales in 675 groups were sighted along 25,440 km of > transect distance flown and 217 body lengths were measured. Using position and > heading data, three major migratory pathways or corridors in the southern > portion of the bight are defined. Those migrating offshore were split almost > evenly between two corridors along the west sides of Santa Catalina and San > Clemente Islands. These corridors converge on the mainland coast between San > Diego and the United States–Mexico border. No whales larger than 11.5 m were > photographed within 30 km of the mainland coast, suggesting that smaller, and > presumably younger, whales use the coastal migratory corridor through the > California Bight. > > A PDF can be downloaded from: http://spo.nmfs.noaa.gov/mfr731/mfr7313.pdf > > Jim Sumich
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