Mysterious death of fish in the North sea – now researchers are faced with a puzzle

the island of Sylt, St. Peter-Ording, Büsum, Cuxhaven, Hamburg: In several Places in Schleswig-Holstein and lower Saxony has washed up on the North sea in the l

Mysterious death of fish in the North sea – now researchers are faced with a puzzle

the island of Sylt, St. Peter-Ording, Büsum, Cuxhaven, Hamburg: In several Places in Schleswig-Holstein and lower Saxony has washed up on the North sea in the last days of dead fish. Including especially herring. Partial mass layers of dead Fish dead on the shore, as pictures show.

In the Bay Grimmershörn in Cuxhaven about would be partially located up to 30 dead young herring on a square metre of Mudflats, reported "the Wadden sea-protection of Cuxhaven". "Many birds feed on young herring in their offspring. Only these dead fish will not be touched,“ it says.

in addition to the primarily affected herring conservationist reports of stranded dead eels and sturgeon, is said to have been found in Hamburg. Both species are considered threatened with extinction.

"yet washed-up fish may only be the tip of the iceberg"

About the reason for the large fish die, the scientists of the world yet. There are several previously unconfirmed theories on the cause of the event. Some of the Work on the deepening of the Elbe river in Hamburg is responsible. You should choke to reduce the oxygen content in the water is dangerous and the fish in consequence.

in the Alliance, "Living the tidal Elbe" brought together environmental associations BUND, NABU and WWF, have reported on Tuesday a criminal complaint against Unknown. In addition, challenge the Hamburg Port Authority (HPA) and the Directorate-General for waterways and shipping (GWDS) as "builders" of the deepening of the Elbe river, all the excavator work immediately to stop as long as the causes for the dramatic fish die not yet been completely elucidated. "The hitherto washed-up fish may be only the tip of the iceberg," say the associations.

experts disagree environmentalist theory

But clearly the cause of the fish dying does not seem to be. So have spoken, in the meantime, increasingly, experts are of the washed-up fish carcasses and other theories brought into play.

"in My opinion, the hypothesis of the toxic blooms of blue-green algae (cyanobacteria) should be checked as the cause in more detail", explains about Henner Hollert, Professor of ecology, Evolution and environmental toxicology at Johann Wolfgang Goethe-University of Frankfurt am Main. This could cause the measure to be such a fish die if mass destruction to take place increases.

The "Remobilisation of sediments due to the deepening of the Elbe are not to die, in my opinion, the reason for the fish," continues the Professor, "since it would then be occurred more likely in the Elbe even stronger". Chemicals are not to be excluded as a reason for the fish die. "But with the existing Information, one can say little."

the fish is made of die people, and the construction work in the Hamburg port area are due, not believe Jörn Coulter sack, the point of contact for fish diseases in the North sea and the Baltic sea from the working area of the marine environment of the Thünen Institute of fisheries ecology in Bremerhaven.

The construction works in Hamburg, could "lead locally to a lack of oxygen, if the silt is applied". But would have to disappear relatively quickly, says the biologist, and that would then affect more than one species, and not primarily herring. "Also, the fish could avoid these areas and would not stay there. So an anthropogenic – human-induced – cause I think this is rather unlikely.“

toxic blue Are dying algae to blame for the fish in the North sea?

The blue-green algae theory hinges bag looks a bit more critical than his Frankfurt colleague. Accordingly, the toxic algae blooms could lead to the extinction to mass. But then you would have to be from his point of view, other species of fish as herring stranded. In the case of current Events, however, that, with few exceptions, only pegs its affected. Other species such as eels and Sturgeons appeared to be only locally in the area of the Elbe estuary affected.

"It can be, of course, that herring, as a plankton-eater will be drawn in the case of algae bloom hit particularly hard, so this is also a possible cause", or limit, or bevy sack. Both explanations – a herring-specific disease, and algal blooms – were, therefore, in his eyes, plausible theories, and Algal blooms relatively quickly, by examination of water samples examined. "If, however, that other types of large-scale affected, it changes the situation. This would then indicate a poisoning.“ Each week provides you FOCUS Online with the most important news from the knowledge Department. Here you can subscribe to the Newsletter.

More information about the evaluation

The Situation should be further analyzed, the experts agree. "To my knowledge, several samples were taken from herring and from the water, which will be examined by the competent bodies of the countries," explains Coulter sack. In addition, it is planned that institutions that are specialized in fish diseases, were such as the Friedrich-Loeffler-Institut on the island Riems or the Department of fish diseases, University of Veterinary medicine Hannover, samples that you might specifically on fish pathogens examined.

"have Also offered to examine the fish, however, we can only perform a macroscopic evaluation of the condition of the fish, no bacterial or virological examination."

marine biologist Justus van Beusekom from the Institute for coastal research at the Helmholtz-Zentrum Geesthacht, refers to a similar incident in 2007, on the island of Sylt has given. Then, too, several hundreds of thousands of dead fish were washed up on the coast. "They suspected that the weather was to blame and too little oxygen in the water was available," says van Beusekom. "To be able to the current situation to better assess, however, would have to be carried out further measurements and studies," says he. "To the washed-up dead fish on the North sea coast, no specific cause is currently known." Until the weekend! The severe weather are being exacerbated, in the Thunderstorm on the most violent PCP Until the weekend! The severe weather are being exacerbated, in the Thunderstorm on the most violent will In a hidden chamber, German researchers make a unique discovery FOCUS Online In a hidden chamber, German researchers make a unique discovery

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Updated Date: 25 June 2020, 17:27

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