A detachable clamping sinker automatically detaches from fishing line after immersion in water. The sinker includes a first weighted half, and a second weighted half that is moveable relative to the first weighted half. An elastic tie assembly couples the first weighted half to the second weighted half. The elastic tie assembly includes an elastic member, and an externally exposed rapidly disintegrating water soluble material linking the elastic member to one of the weighted halves. The elastic member under tension imparts a force holding the first weighted half against the second weighted half to clamp a fishing line therebetween. The disintegrating material when dry withstands a casting load and when wet rapidly dissolves to release the tension that clamps the fishing line. The weighted halves may be biodegradable or dissolvable.
