epiplankton

Century Dictionary and Cyclopedia

1. n. The animals and plants which float or swim at the surface or above the hundred-fathom line, considered collectively and in contrast with the dwellers in deeper water; the pelagic plankton (which see, under plankton).

Wiktionary

1. n. Plankton normally living in the top hundred fathoms of a body of water (at a depth of about 180 metres or less).