Also, here and there a heavy, sucking swirl on the smooth slope of a wave would show where some very big fish was taking toll of the pinky swarms.

The whale kept her eye on these ponderous swirls with a certain amount of suspicion, though not really anticipating any danger here.
"She was just about coming to the conclusion that one can have enough, even of shrimps, when, glancing downwards, she caught sight of a long, slender, deadly-looking shape slanting up toward her through a space of clear water between the armies of the shrimps.

She knew that grim shape all too well, and it was darting straight at her baby, its terrible sword standing out keen and straight from its pointed snout.
"In spite of her immense bulk and apparently clumsy form, the whale was capable of marvelously quick action.

You see, except for her head she was all one bundle of muscle.

Swift as thought, she whipped herself clear round, between her calf and the upward rush of the swordfish.
She was just in time.