Abstract: Two half sections of bamboo defining three chambers contain a pre-inflated helium gas balloon with a radio beacon, two bags of surface dye, and bait fish. The sections are secured together by multiple wrappings of line ending in hooks or lures. When the associated probe is deployed, the windings unravel in free-fall--separating the half sections and dispersing the bait. The balloon is released and descends to the water surface, where the line hooks and the bait submerge. An aquatic nibble causes the balloon to bob. A more forceful bite separates the bags of dye--creating a surface marker. If a hook is set, the line also extracts a pin from the balloon--activating the radio beacon and freeing it to rise to an altitude where an induced leak soon results in the balloon redescending to the surface of the water. Upon reaching the surface, normal wave propagation forces out the residual gas and the balloon, being no longer buoyant under the weight of the radio beacon, sinks to the ocean bottom.

Abstract: An elongated resilient cylindrical tube capable of returning to its original shape after being forceably deformed has a closed end and an open end. A sleeve is fixed to the open end of the tube. The tube is filled with buoyancy material and a plurality of different colored dyes, and the sleeve is sealed with a weighted plug coupled to a fish hook. The probe is submerged in the water, and descends due to the weight of the plug. The plug unseals the sleeve when the force of a hooked fish is exerted upon it, causing the probe to ascend toward the surface. As the probe ascends, the different colors of dyes are successively expelled from the probe. The color of the dye which is first expelled by the probe when the probe reaches the surface is indicative of the depth at which the plug was removed from the body.