Protecting marine animals in the world's largest brackish water sea
The Baltic Sea, surrounded by nine countries, is unique as the world's largest brackish inland sea. Its low salinity and limited water exchange create a fragile ecosystem supporting harbor porpoises, grey seals, harbor seals, and endemic fish species. Eutrophication from agricultural runoff, persistent pollutants, and climate change create severe welfare challenges.
The Critically Endangered Baltic Proper harbour porpoise subspecies faces extinction from gillnet bycatch. Acoustic deterrents (pingers) on fishing gear reduce but don't eliminate entanglement. The critically low population size means individual deaths are irreplaceable losses.
The Baltic contains some of the world's highest concentrations of persistent organic pollutants including PCBs, DDT metabolites, and dioxins. These bioaccumulate in seals, porpoises, and top predators, causing reproductive failure, immune suppression, and cancer. Despite bans on these chemicals, legacy contamination persists for decades.
HELCOM (Helsinki Commission) coordinates Baltic protection among all nine coastal states. The Baltic Sea Action Plan targets nutrient reduction, fisheries management, and hazardous substance elimination. Gillnet restrictions in critical porpoise areas represent the most urgent welfare intervention. Sweden and Germany have designated strict porpoise protection areas.