New figures show that more than one in three of Denmark’s 108 coastal waters have already been hit by oxygen depletion this year, the third year in a row with alarming levels.
DR reports that the measurements come from the Danish Agency for Green Land Conversion and Water Environment. The Danish Society for Nature Conservation calls the level alarmingly high. The organization compared the newest readings from 40 locations with the past two years at the same sites.
One area where the effects are clearly felt is Helnæs Bugt near Faaborg on Funen. Recreational angler Kent Andersen has fished there for many years and says conditions have never been worse. According to Andersen, the decline began around five years ago.
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Andersen told DR that Helnæs Bugt used to be one of the best places on Funen to catch sea trout. This year he has not heard of anyone landing a single one. He normally catches about 350 trout a year along Danish waters, but has caught only 50 this year.
Researchers point to nutrients and warmer seas
Jens Würgler Hansen, senior adviser at the Department of Ecoscience at Aarhus University, said the situation is not good. Per Hansen, oxygen depletion is establishing itself quickly, particularly in the waters around Funen. He noted that much of it falls into the severe category.
According to Hansen, two factors are driving the worsening. One is too many nutrients, such as nitrogen, in the marine environment. The other is climate change, which raises sea temperatures and reduces wind, conditions he described as a very bad cocktail.
As reported by DR, Denmark measured its worst oxygen depletion on record in 2023, and that record was surpassed in 2024. Hansen said 2025 was heading toward similar conditions, but strong winds in September slowed the development. He said the figures show a substantial and continuing problem in the marine environment.
Folketing vote set for Thursday
The figures come as the Folketing prepares to finalize new rules on nitrogen. On Thursday, parliament is set to adopt a law allowing far stricter regulation of agricultural nitrogen discharges. According to Hansen, most of the nutrient load reaching the sea comes from farming.
Minister for Nature and Animal Welfare Christian Rabjerg Madsen of the Social Democrats called the task of solving oxygen depletion an obligation that cannot be avoided. He said the case shows the complexity involved and that he understands the frustration among farmers.
The minister said he is concerned about the numbers being presented. He called it serious that Denmark sets a new negative record year after year. According to Madsen, the challenge cannot be solved without reducing nitrogen discharges from agriculture.
Hansen said there is no way around marked reductions in the amount of nutrients reaching the sea. Andersen, the angler, said the area was full of life 30 to 40 years ago, with garfish and cod. He described the same waters today as a desert.
