Two data sets concerning organic contaminants are included here to aid in assessment of the sea otter population collapse in southwest Alaska. One data set consists of levels of organic pollutant compounds found in wild sea otter blood collected from captured animals in 1997 (Jessup et al., 2010). These sea otters were captured from islands in the western Aleutians and from outside the area of population collapse, in southeast Alaska near Cross Sound. Another data set consists of levels of organic pollutant compounds found in blue mussels collected from multiple sites along the Aleutian archipelago and from the Cross Sound area in southeast Alaska in 1994-1996 (Reese et al., 2012). These data support the following publication: M. Tim Tinker, James L. Bodkin, Lizabeth Bowen, Brenda Ballachey, Gena Bentall, Alexander Burdin, Heather Coletti, George Esslinger, Brian B. Hatfield, Michael C. Kenner, Kimberly Kloecker, Brenda Konar, A. Keith Miles, Daniel H. Monson, Michael J. Murray, Ben Weitzman and James A. Estes, 2021, Sea otter population collapse in southwest Alaska: assessing ecological covariates, consequences, and causal factors: Ecological Monographs References: Jessup, D. A., C. K. Johnson, J. Estes, D. Carlson-Bremer, W. M. Jarman, S. Reese, E. Dodd, M. T. Tinker, and M. H. Ziccardi. 2010. Persistent organic pollutants in the blood of free-ranging sea otters (Enhydra Lutris Ssp.) in Alaska and California. Journal of Wildlife Diseases 46:1214-1233. Reese, S. L., J. A. Estes, and W. M. Jarman. 2012. Organochlorine contaminants in coastal marine ecosystems of southern Alaska: inferences from spatial patterns in blue mussels (Mytilus trossulus). Chemosphere 88:873-880.