Diving behavior of lipped hard-lure changed by the body shape in the retrieving process

Abstract

The flume tank and the field experiments were conducted to clarify the relationship between the body shape of floating hard-lure and the diving behavior in the retrieving process. Experimental lure-bodies were made up of the same rectangular shape (Lb = 65 mm, Lw = 15 mm) in the plane view and of different heights (13 mm ≦ Lh ≦ 65 mm) of elliptic shape in the side view. Trial lures with the same lip were used in both the experiments at velocities of 40, 60 and 80 cm/s in the flow or in the retrieve. Diving depth, attack angle and tension on a towing line of the lure were measured in the tank test. The lure behavior was also recorded by video camera from the top and the side of flume tank. Diving pattern of the lures was investigated with 4 transducers of fish finder within 20 m retrieving course in the field experiment. As increasing the ratio of axial length κ = Lh/Lb as a parameter for the elliptic lateral shape of the body, the horizontal vibrating angle β of the lure was enlarged and the diving depth was shallower. It was indicated from these results that the diving behavior of the lure could be controlled by the value of body shape κ.