Complex sentence: They eat mainly on other fishes as well as crustaceans and aquatic insects.Trout cod reach sexual maturity at 3-5 years.It was once abundant but is now gravely threated by overfishing and environmental factors.
Split into simpler sentences: They eat mainly on other fishes as well as crustaceans and aquatic insects. Trout Cod were once abundant, but are now gravely threated by overfishing and environmental factors.