I was sitting by the aquarium at my Doctor's office watching the fish. How do fish mate?

[eppur_se_muova]

14. No, they bury their eggs in the sand, so not quite as messy. Herring are known to have huge seasonal coastal spawnings.

I don't know what other fish do, but herring form very large schools, so that probably has a lot to do with it. Sheer force of numbers -- what programmers call the "Mongolian hordes" approach (ironically, not actually the devastating tactic the Mongols usually used. They preferred to flee into a pre-set ambush by concealed reinforcements, then turn and finish off their pursuers).

Google "satellite imagery of herring milt" to get some idea of the scale involved.