Several factors are often considered, ranging from overfishing to rising sea temperatures. We have one such example right on our doorstep. In the Baltic Sea, the herring stock has been declining for several years. The herring has been named Fish of the Year 2021 to draw attention to the problem. For years, different approaches and assumptions have been used to explain the herring decline. These could not be scientifically substantiated by long-term measurements.
After more than 10 years of research, the scientific explanation has now been found: Rising water temperatures are the cause of the decline in the herring population.
The CTD probe has made a major contribution to this realisation and you can find out exactly what role it plays below.