Complex sentence: Yellow perch have such an extensive impact on trout species in the bodies of water in which they were introduced and established, they caused a drastic change in the food habits and reduced the growth rates of the trout by more than 50% in some locations.
Split into simpler sentences: Yellow perch have such an extensive impact on trout species in the bodies of water in which they were introduced and established. They caused a drastic change in the food habits and reduced the growth rates of the trout by more than 50% in some locations.