The overconsumption of fish has been a detriment to the ocean’s health for many years, now a study has found that the mercury concentration within said fish peaks in the winter into spring seasons. Why is that? Let’s take a look—

A year-round study conducted in Finland took a deep look into their boreal lake fish population and the natural, seasonal cycles that pair with them. According to the study, summer is the growing season for fish, followed by weight loss during winter and into spring for spawning. During the winter time, naturally food becomes less plentiful and significant environmental and temperature changes occur. This means that the energy to grow does not come in high doses, resulting in weight loss and starvation. During this period, mercury levels are about 30 to 40% higher than summer and autumn seasons. 

The field research conducted during the cold months is lower than warmer months, so significant data is inconclusive. Cold months have a large impact on natural cycles (as previously stated), but due to inconclusive research, many do not understand to what extent these months have on the lake’s ecosystems. Their current findings are very interesting—both the perch and pikeperch fish species are important for both recreational and commercial fishing in the boreal region, but during the winter months these fish tend to feed on other fish. And despite the higher mercury levels during these months, the overall levels are below the standard health limit. 

The study, to its most accurate degree, provides valuable information and insight on the dynamics and challenges these fish populations face during seasonal changes. This study will help further along efforts in monitoring the mercury levels in said fish. The authors came to the conclusion that it would be the sustainable solution to have commercial and recreational fisheries decrease activity during the spawning time, due to high mercury levels still in the population’s system from the winter. This can give major insight to the surrounding areas, and even overseas to match up seasonal dynamics to other regions to find the best possible time to fish and consume.