The pronounced seasonal changes of warm open-water and cold ice-covered seasons dominate natural cycles in Finnish lakes.
The pronounced seasonal changes of warm open-water and cold ice-covered seasons dominate natural cycles in Finnish lakes.
« Summer is the growing season of fish followed by weight loss during winter and spring spawning time, » says research team leader, Professor Kimmo Kahilainen from the Lammi Biological Station, University of Helsinki.
Significant changes in temperature and other environmental factors during colder months result in lowered metabolism in fish. Additionally, less food is available for fish during this harsh timeframe. Under these conditions, eventually the energy required to grow is not met by the amount of energy taken in, resulting in weight loss and starvation.
This seasonal cycle means that fish mercury in winter and spring can be up to 30%–40% higher compared to summer and autumn.
