You can guarantee that in Japan, they have exhausted the best ways to eat certain seafood at certain times of the year, and of course paired with other foods.
Fall is the season that is likely most anticipated by the seafood-loving Japanese populace. Just as it is the time of major vegetable, and more importantly rice harvesting, it is also the time of fish proliferation. That being said, fish eggs are most abundant in the fall, and different varieties can be enjoyed as a topping to a number of tasty dishes.
Tarako, Mentaiko, Kazu-no-ko, and Sujiko are some of the most common fish eggs to be enjoyed over the fresh rice harvested all over Japan in the fall. I would recommend mentaiko if you are not very accustomed to fish eggs, as they are probably the most mild in flavor.