Friday, May 13, 2011


On some Californian beaches there is a spectacle like no other during nights of a full moon. Millions of fish launch themselves ashore in an apparent mass suicide attempt.

Although for a fish to launch itself onto a beach may seem like a life-threatening action, it is in fact simply a spawning technique. It is used by one or two fish species, including the grunion and the capelin. Many of these fish die during these dangerous onshore excursions, but it is all in the
cause of breeding. The goal is for egg- and sperm-laden fish to be swept far up shore by the waves and to be left stranded there for a few seconds. During this brief period, females bury the back half of their bodies into the soft wet sand, positioning themselves in an upright position. As this happens, a number of males surround each female. The female then releases her eggs under the sand, and the males release their sperm, thus fertilizing the eggs. With luck, the next large wave will sweep the females and males back into the safety of the surf.

Spring Tide Hatching
GrunionSpawning happens during the full moon when tides are at their highest. The eggs will remain buried in the sand above water level for the next two weeks, until the highest tides are due again. During this time, the embryos develop inside the eggs. They hatch within minutes of being wetted by the first waves of the incoming high tide and are washed into the sea. It takes the young fish one year to mature. They then return to the beaches to breed and take part in the same dangerous life-and-death ritual.


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