Creatures of the Abyss by Murray Leinster — Read

The next morning the _Esperance_ headed southeast over a sunlit sea. First, of course, the crew examined the sea's surface for miles around. As expected, there was nothing remarkable to be observed. Davis did point out that there were no fish jumping, which was an indication that there were not as many fish as usual in this part of the ocean. But it was hard to be sure. There is no normal number of times when fish will be seen to jump. They usually jump to escape larger fish that want to eat them. The number is pure chance. But there seemed to be almost no jumps at all this morning.

It was not discussed at length, however. All the ship's company was curiously reluctant to refer to the events of the previous night. In broad daylight, a detached review was simply impractical. With gulls squawking all about, with seas glinting in the sunshine, with decks to be washed and breakfast to be eaten, and commonplace, routine ship-keeping to be done, the adventure of the patch of shining sea seemed highly improbable. Terry felt that it couldn't really have happened. To discuss it seriously would be like a daylight ghost tale. One was unable to believe it in daylight. It was better ignored.