How does the ability to produce 3000 to 6500 eggs benefit the species

If a species has the ability to produce that many eggs, that means it has the ability to overproduce. This is beneficial because while the parents cannot provide excessive amounts of parenting/care for each of the offspring, only the fittest will end up surviving. Once the fittest survive and reproduce, they will pass on the trait or traits that made them fitter to their offspring. Then the process will repeat, resulting in a better population over time. Thus, the amount of favorable traits will accumulate in the species; this, in other words, is a benefit to the species.

more offspring are likely to survive and reproduce