Seals constitute an important part of pelagic food webs as top predators and their health is essential for maintaining a good ecosystem balance. These organisms are at the highest trophic level and can be used as proxy for harmful substances since these compounds are stored in the body fat (adipose tissue) and organs of the animals. This monitoring program is focused toward determining the health status of seal populations via autopsies of animals that are collected and sent to the Swedish Museum of Natural History. In addition, the program is also aimed for finding and measuring potentially harmful substances in biota. Sampling provides information to describe the cause of death among seals. Data are collected and analyzed according to methods described by the Swedish Environmental Protection Agency (http://www.naturvardsverket.se/upload/stod-i-miljoarbetet/vagledning/miljoovervakning/handledning/metoder/undersokningstyper/kust-hav/patologi-hos-grasal-vikare-sal-och-knubbsal-ver-1-1-2014-03-19.pdf). If the exact position of the findings are not known, the position will be stored as the county town of the county in which the seal was found.