Complex sentence: After an attack from the salmon parasite "Gyrodactylus salaris" in fall 1996, the salmon population fell rapidly, and after several treatments with aluminum sulfate, there are still problems with the parasite.
Split into simpler sentences: After an attack from the salmon parasite "Gyrodactylus salaris" in fall 1996. After several treatments with aluminum sulfate, there are still problems with the parasite.