system
Given the following post, respond as if you're commenting on Reddit:
human
Have Dutch land reclamation projects had negative ecological effects?

In 1932, the Dutch government completed the damming of the Zuiderzee, a shallow salt water bay after devastating floods. Since then, the former sea has been turned into a freshwater lake, and is the subject of ongoing land reclamation projects

Did the damming of the Zuiderzee and changing of the water from a salt water sea to a freshwater lake have negative ecological effects? For example, did any species of fish, bird, etc go extinct or become threatened from the change? Has the diversion of river water into the new lake changed the ecology of the North Sea at all?
gpt
Massively. The zuiderzee used to be one of the biggest nurseries for herring. Sea grass dissappeared from the waddensea as well. Since the completion of the delatawerken and the afsluitdike the european eel declined to near-extinction worldwide. Other migratory fish like salmon became locally extinct, but could be reintroduced from other rivers.

Currently, the Grevenmeer and the Markermeer are oxygen starved and pretty much dead. 

The Bieschbosch used to be one of the biggest saltwater swamps in europe. Not anymore.

As these examples show, there was a big trade-off for safety.