Fine.
What has happened is between 16 and 40 species of crustacian has evolved in only 40 years. The creation by man of a new niche made an opportunity for creatures with genes that permit varying amounts of salinity. Before that niche, the environment was stable. After it was filled, the niche was filled, the species still evolve, but outliers are trimmed. With the niche newly created (by man) the evolution rate radically increases.
I wouldn't know this unless I worked at Pt. Mugu for a year. We are now restricted on what we could do in the Mugu lagoon, as each of these species are endangered, and protected. Nothing like them anywhere in the world.
Interesting experiment, no?
Any data?