Strike Trigger Mechanisms (Lateral Line vs. Inner Ear)

How many times have you been sitting in your boat in October and witness a flock of birds or a school of shad after been frightened? To our amazement, they never collide with one another during their wildest dips and dives. How do they do it? Well it is still one of nature's most studied phenomenons. Actually, it has a lot to do with how fish detect prey, resulting in what we wait for...the "strike."

Fish use two mechamisms to detect sounds, vibrations and movement which are the lateral line and inner ear systems, both independent but sharing common principles of operation. The lateral line system measures and evaluates pressure differences caused by wave action from surround objects. The lateral line consists of pores that open into a canal containing nerve hair cells. These cells are sensitive to vibration and pressure changes which send impulses to the fish's brain. These cells change mechanical energy into electrical energy. It is the lateral line that maintains the fish's position in a school and the major mechanism in the decision for the fish to strike. Research indicates the lateral line may agument visual prey dettection at high light levels.

A fish can also hear long distances with their inner ears which consist of fluid-filled canals and chambers. The lower portion of the inner ear is responsible for sound detection which contains a calicified ear stone called an "otolith." The otoliths are located just behind the brain and are approximately three times denser than the fish's body so when struck by sound waves, they vibrate at a different frequency and amplitude from the fish's body. Research indicates there are magnetic materials in the otolith of fish and birds which raises the possibility that these structures may be key elements in the elusive magnetic sensory system. The lateral otolith comprises tiny magnetic particles of low inertia that are displaced by imposed magnetic fields providing fish and birds with geomagnetic sensory input from which the brain would infer navigation information.

I know this is a little technical and most of us would just as soon be away from work, enjoying the "bite" and not having to worry about the "how."