2023-11-24 09:47:00
Staatsbosbeheer has captured almost all sunfish in five fens in the Mastbos near Breda with traps: more than 100,000 fish have been killed.
Sunfish were brought to the Netherlands from North America for the trade in fish for garden ponds. This trade has now been banned, but the calf has already drowned. Pond fish keepers would rather throw their surplus fish into a canal or lake than eat them. And this is how exotic fish end up in nature. (Exotic) pond plants are also dumped in nature, with fish eggs and all. These exotic plants have no enemies here and multiply happily. This also applies to sunfish, which are currently causing a slaughter among young amphibians and invertebrates.
In the fens in the Mastbos, sunfish threatened to wipe out amphibians and invertebrates. Only when they are gone do the bass start to eat each other and the situation can stabilize, but then you have tens of thousands of American sunfish in a lake and almost nothing else.
The purification campaign took place in 2012. The Mastbos is a walking forest; there is a good chance that new sunfish will be released into the water. Moreover, you can never catch all the fish and eggs. That is why pikes were released following the catch. Laura van Veenhuisen and Hein van Kleef of the Bargerveen Foundation have monitored the effect of this and are publishing their findings in the latest edition of The Living Nature.
Sunfish have not been caught in one fen for years: mission accomplished. In the other fens yes, but ninety percent less. There are still a few thousand of them, but the pikes are doing their job. Good news for aquatic life: water bugs, caddisflies and dragonflies are doing much better once more and a very rare dancing mosquito has even been found. That is Omitted Caledonian, which had not been seen in the Netherlands for fifty years. Unfortunately, the amphibian population is not yet recovering.
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#Pike #sunfish #Fidelity