Effects of light on the efficacy of traps forNautilus pompilius

Abstract

Nautilus pompilius is usually caught using baited traps set on the bottom at depths of over 100 m. Since laboratory tests have shown that the animals are positively phototactic, the effects of light on the efficacy of trapping was studied by setting pairs of traps at 450 m off the reef at Suva, Fiji. The traps were matched in design but one was illuminated and one dark. Illuminated traps caught significantly more Nautilus (P<0.001), suggesting that Nautilus is attracted by light in the natural environment. The function of this behaviour is considered, and it is suggested that it may help the animals find their sources of food.