Why are there no insects in the open sea?

J Exp Biol. 1998 Sep:201 (Pt 17):2461-4. doi: 10.1242/jeb.201.17.2461.

Abstract

The air-filled tracheal respiratory system of insects prevents them from diving deeply in water. It is argued that this is the major factor in preventing insects from colonizing the open sea: they cannot descend sufficiently deeply in the daytime to escape being eaten by fish.