05/18/2025
Today marks International Day of the Baltic Harbour Porpoise – a chance to celebrate and raise awareness for one of the world's most endangered whale populations. (Yes, porpoises are whales!) These remarkable animals have called the Baltic Sea home for nearly 9,000 years, about the time the Baltic Sea formed after the last ice age.
But their ancient presence doesn't guarantee their future. Scientists estimate between 70 and just over 1,000 Baltic harbour porpoises remain, with the most likely number sitting around 500 individuals. Getting an exact count is incredibly challenging – these shy creatures surface only briefly and live scattered across a vast area. Researchers rely on underwater microphones to detect their echolocation clicks rather than trying to spot them visually. The ongoing SAMBAH II study is working to update these population estimates.
The reality is sobering. A century ago, thousands of these porpoises thrived in Baltic waters. Today, fewer than 250 adults likely remain capable of reproduction. Their biggest threat comes from accidental capture in fishing nets, though they also face increasingly noisy seas, water pollution, and changes to their food sources. For such a small population, losing even one or two animals each year to fishing gear is devastating.
Yet there's reason for hope. In 2024, the Baltic harbour porpoise gained the highest level of international protection when it was added to the Convention on Migratory Species' most protected list. Countries around the Baltic are implementing fishing restrictions and requiring boats to use acoustic warning devices in certain areas. Denmark recently became the first Baltic nation to ban ships from discharging harmful waste water in its territorial seas, with the ban taking effect this July.
The next few years will determine whether this population survives or vanishes forever. While governments are taking important steps, we all have a part to play. Supporting sustainable fishing practices, working to reduce pollution, and sharing knowledge about these incredible creatures can help ensure that future generations will share their seas with Baltic harbour porpoises.
