Abstract: This disclosure is concerned with creating relatively darkened or light-shielded coverings along and upon a substantial selected area of the surface of a pond or other confined fish-holding water volume in the form of surface turbulence generated over said selected area by water spraying or other agitation, with calm illuminated feed zones adjacent but external to said selected area.

Abstract: This disclosure is concerned with utilizing the lower dark strata of deep sea cages and the like for fish, such as salmon, as a stress-relief resting volume, while providing specially contoured artificial illumination beyond daylight hours that is limited to upper strata of the cages where feed is periodically applied, and which illumination is prevented from penetrating into the dark strata, but rather provides a predetermined upper laterally illuminated feed-exposing strata, viewable diffusely from below by the fish in the dark lower resting strata.