Complex sentence: Even though mouthbrooding requires more energy by the male, there is also a greater chance of survivability of his young, and therefore, reproducibility and continuation of his genes; the eggs are not defenseless while in their father's mouth.
Split into simpler sentences: Even though mouthbrooding requires more energy by the male, there is also a greater chance of survivability of his young, and therefore, reproducibility and continuation of his genes. The eggs are not defenseless while in their father's mouth.