Why are eggs laid in large quantities in ponds?

Assuming you are talking about amphibians such as frogs and toads it because they have a very high predation rate. Just about everything that lives in water will eat the eggs, tadpoles and froglets. So to keep the species going they need to lay large numbers of eggs to ensure that a small percentage survive to adulthood. read more

Female salmon, for instance, will lay anywhere from 1,500 eggs to about 10,000 at one time. Among these eggs, only around 10 will successfully spawn salmon. The eggs themselves are highly sensitive, which can make it difficult for them to survive and hatch. read more