Complex sentence: High levels of organic chemicals accumulate in these animals since they're high up on the food chain they have large reserves of blubber, more so for toothed whales as they are higher up on the food chain than baleen whales.
Split into simpler sentences: High levels of organic chemicals accumulate in these animals since they are high in the food chain. They have large reserves of blubber, more so for toothed whales as they are higher up the food chain than baleen whales.