Complex sentence: In addition, the presence of dams redistributes the remineralization of nutrients as research estimates as much as 7 to 15 percent of the migrating salmon stock perishes traversing at each consecutive dam.
Split into simpler sentences: In addition, the presence of dams redistributes the remineralization of nutrients. Research estimates as much as 7 to 15 percent of the migrating salmon stock perish as they cross each consecutive dam.