Modeling bird mortality associated with the M/V Citrus oil spill off St. Paul Island, Alaska

We developed a model to estimate the number of bird carcasses that were lik ely deposited on the beaches of St. Paul Island, Alaska following the M/V C itrus oil spill in February 1996. Most of the islands beaches were searched on an irregular schedule, resulting in the recovery of 876 King Elder carc asses. A sub-sample of beaches were intensively studied to estimate daily p ersistence rate and detection probability [Fowler, A.C., Flint, P.L., 1997. Marine Pollution Bulletin]. Using these data, our model predicted that an additional 733 +/- 70 King Elder carcasses were not detected during our sea rches. Therefore, we estimate that at least 1609 +/- 70 King Elder carcasse s occurred on beaches as a result of the spill. We lacked sufficient sample size to model losses for other species, thus we applied the estimated reco very rate for King Elders (54%) to other species and estimate a total combi ned loss of 1765 birds. In addition, 165 birds were captured alive making t he total estimated number of birds impacted by the M/V Citrus spill 1930. G iven that oiled birds occurred in places on the island which could not be s ystematically searched combined with the fact that it was unlikely that oil ed birds that died at sea would have been recovered during our searches [Fl int, P.L., Fowler, A.C., 1998. Marine Pollution Bulletin], our estimate of total mortality associated with the spill should be considered a minimum. ( C) 1999 Elsevier Science B.V. All rights reserved.