Grunion fish

grunion fish
   Grunion is a smelt found off the coast of Cali­fornia. The grunion, Leuresthes tenuis, has remarkable breeding habits. On the second, third, and fourth nights after the full moon from March to June these fish come in with the high tides and flip onto the sandy beach. Each female, attended by a male, quickly deposits eggs, which are immediately fertilized and buried two to six inches in the sand. The fish then flip back into the water. In about two weeks, when the eggs are ready to hatch, they are washed out of the sand by the high tides accompanying the new moon. This cycle is an outstanding example of animal adaptation to lunar rhythms.