Marine bird and sea otter population abundance of Prince William Sound, Alaska: trends following the T/V Exxon Valdez oil spill, 1989-2007

• Main Author: Irons
• Format: Dataset
• Language: unknown
• Published: Gulf of Alaska Data Portal
• Subjects: population trends; seabirds; sea otters; Prince William Sound; Montague; Orca; Alaska
• Online Access: https://search.dataone.org/view/df35r.7.27

We conducted small boat surveys to estimate marine bird and sea otter populations in Prince Willi am Sound, Alaska during March (“winter”) and July (“summer”) 2007, using methods developed in 1989-91 (Klosiewski and Laing 1994). We examined trends of marine birds in the oiled and unoiled areas of PWS between 1989 and 2007. We consi dered an increasing population trend evidence that recovery was occurring, and no trend or a decreasing trend evidence that populations were not recovering. We also compared trends between the oiled and unoiled regions; we considered a significantly greater slope in oiled area trends evidence that a population was recovering, while a significantly grea ter slope in unoiled area trends indicated continuing oil spill effects for that taxon. Our data indicated that most t axa for which injury was previously demonstrated were not recovering. During winter surveys, three taxa (“loons,” Comm on Loons, and “scoters”) had increasing population trends, while fourteen taxa (Bald Eagles, Black-legged Kittiwakes, Buffleheads, Common Murres, “cormorants,” “goldeneyes,” “grebes,” Glaucous-winged Gulls, Harlequin Ducks, “mergansers ,” Mew Gulls, Marbled Murrelets, Northwestern Crows, and Pigeon Guillemots) did not exhibit any trend toward recovery. During summer surveys, three taxa (“cormorants,” Glaucous-winged Gulls, and Northwestern Crows) showed trends consis tent with a recovering population, and fifteen taxa (Bald Eagles, Black-legged Kittiwakes, Black Oystercatchers, “gold eneyes,” Harlequin Ducks, “loons,” Common Loons, Kittlitz’s Murrelets, “mergansers,” Mew Gulls, Marbled Murrelets, Com mon Murres, Pigeon Guillemots, “scoters,” and “terns”) showed no trend toward recovery. Densities of sea otters in Ma rch and July surveys showed no trend toward recovery.