The intensity of scattered light in turbid seawater is a major factor in the turbiditaxis of Japanese anchovy larvae

Abstract

Positive taxis toward turbid seawater (turbiditaxis) is a well-known key factor in the formation of Shirasu (Japanese anchovy larvae, Engraulis japonicus) fisheries in coastal waters. The physical characteristics of turbid seawater, including color, particle size, underwater light intensity, and scattered light intensity, were studied to examine the mechanism by which turbidity lures the larvae using four food colors, polishing powder, and five water colors. The results of taxis tests comparing turbid materials with different characteristics, led to the conclusion that the scattered light intensity of turbid seawater was the key factor causing positive turbiditaxis in anchovy larvae.