Port's marine life
City ecologist and port biologist Martin Melchers has come across several exotic passers-by in the 65 years that he has been strolling through the port of Amsterdam. The latest special finds were the American blue sea crab, Japanese brush crabs and the South American brackish water horn. They probably ended up in the Amsterdam harbour 'by accident' via ballast water.
Melchers is commissioned by the port authority to study biodiversity in the port of Amsterdam. He joins professional fishermen to study the animals under and above the water. What about this biodiversity in the port? Do we have enough sea bass and glass eels in the water?
Amsterdam Wildlife
''The number of bass is increasing,'' Melchers says. ''Normally they reproduce in the south of England, but we are now seeing them doing the same in the Western Harbors. The harbors are full of grouper fish and glass eels." The city ecologist is currently working on a sequel to the film Amsterdam Wildlife and in it he follows the journey of the elvers, among other things. The route through the Nieuwe Zeesluis to Halfweg, where a stream of fresh water can be found. There they grow up to become eels.
Impact new sea lock
The arrival of the new sea lock is also an interesting part of the research. Whether the world's largest sea lock will affect nature Melchers cannot yet say for sure. However, he does know from experience that both living and working do not always have a positive effect on biodiversity. "Where there are people, nature is secondary. By the way, vacant lots or close to the frayed edges of the city are good areas for nature. The edges of the city are the richest for nature. Lots of things grow and flourish here! You can see this in the harbor as well."
Mini-evolution behind the station
The harbor is a special and fun area to explore, Melchers believes. "Ships take various species from all over the world. With the arrival of exotics, the underwater world is changing rapidly. Where Darwin wrote in his books that evolution takes thousands of years, we see the opposite happening in the IJ. For example, behind the central station I discovered a mini-evolution of the American long-loop rib jellyfish. The DNA of this jellyfish is different from its peers."
