25. What kind of biological cycle is shown by grunion?
Lunar cycle. Their activity is controlled by the tides. When the tides are 1-3 days past the highest tides of the month, the grunion will swim ashore and the females will dig in with their tails laying their eggs a few inches below the sand. The decreasing height of the high tides over the next few days will deposit more sand over the eggs. The eggs are above the water line for about 10 days and will develop. As the tides get higher, sand is eroded away from the surface and the fish larvae will emerge.