I am severely allergic to shellfish, yet when I accidentally drink some seawater I don’t get an allergic reaction. How come the millions of fish don’t just contaminate the water with their allergens?
Millions of fish is an understatement. Estimates put it at 3,500,000,000,000 fish.
There’s a lot of water in the ocean as well. Estimates put it at 1,260,000,000,000,000,000,000 litres.
That comes out to about 1 fish per 360,000,000 litres of water, quite diluted down.
Concentration. When you bath in the ocean do you constantly step on fish or are they everywhere? There’s very little fish per liter (small concentration), but the ocean is huge, so there’s still many fishes.
The ocean is huge. Takes up most of the planet. It would take a lot of allergens to notice it in that many gallons of water.