I hadn't heard of this before (the bit about the Suez Canal causing big changes to Mediterranean fish species):
Redistribution of species and interchange will cause a tremendous increase in fish
biodiversity in coastal areas around e.g. Greenland and Svalbard, and
thus dramatic changes to interactions between species.
History has shown that such biotic interchange can result in severe ecological consequences. For example, the construction of the Suez Canal in 1869 resulted in the invasion of the Mediterranean Sea by Red Sea marine fauna. The Mediterranean fish community is now dominated by Red Sea fishes, and this has had harmful ecological and economic consequences for Mediterranean biodiversity and its fishing industry.