Grunion

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Q 1.
	What fish lays its eggs on land?
Q 2.
	I maintain that there is a fish in California which lays its' eggs on the beach at certain times, but my friend bets me there is no such thing. Can you confirm this for us?
Q 3.
	How deep in the sand grunions deposit their eggs?
Q 4.
	In a pasture near my home, there is a hollow in which rain accumulates for several months of the year: Although it has no connection to any other body of water, the newly formed pond is quickly populated by small minnowlike fish that persist until it dries up. Where do these fish come from?


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	Q&A 1.	What fish lays its eggs on land?
	This is the famous grunion, Leuresthes tenuis, one of the Atherinnid fishes of the California coast, limited in range from Point Conception southward to the northern portion of Lower California. Near relatives of the grunion are the silversides fishes, which are most commonly used for bait, locally. The grunion is a small fish which deposits its eggs on the beach in summertime, always appearing for this purpose on the 1st, 2nd, 3rd, and 4th nights after the highest tide of the series at the full of the moon or the new moon. Precisely at 15 minutes after the crest of high tide grunion appear, allowing themselves to be washed ashore as far as possible by the incoming waves. Spawning takes place very quickly, the female lying partially buried in the sand while the males curl about her as the eggs are laid. In about 20 seconds the next wave brings in a new swarm of grunion and carries the spent ones back out to sea. Spawning stops within an hour and the eggs are incubated about four to six inches beneath the moist sand until liberated by the next spring tide, two weeks later, when they hatch. Since grunion are delicately flavored little pan fish, they are caught in great numbers off Long Beach and other spawning ground along the California coast as they come ashore.
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	Q&A 2.	I maintain that there is a fish in California which lays its' eggs on the beach at certain times, but my friend bets me there is no such thing. Can you confirm this for us? Chicago, Illinois
	The grunion, Leuresthus tenuis, belonging to the silverside family, deposits its eggs in the sand at the high-tide mark along the sandy beaches of southern California. This occurs one to three days after the highest spring tide, and the eggs are buried two or three inches beneath the surface of the sand. Here the eggs remain and develop until two weeks later, and a second high tide once more covers them and they are now ready to hatch. The timing involved between the deposition of eggs and the height of the tide is amazing, for if the eggs had not been laid just after the highest spring tide, rather than during the highest tide, there is the possibility that the next high spring tide two weeks later might not have been quite so high, thus preventing the eggs from being reached by the water, and, since they are ready to hatch, they could not survive another two weeks. Furthermore, by being laid after, instead or before, the highest tide, they would be unlikely to be washed out of the sand before they had fully developed, since each successive high tide would be slightly lower until the spring tides began again.
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	Q&A 3.	How deep in the sand grunions deposit their eggs? New Orleans, Louisiana
	The beach-spawning grunion deposits its eggs in pods two or three inches below the surface. These fish usually spawn on the high spring tides which accompany the full and the new moon. As a result of tidal action after the eggs have been deposited it is possible for the eggs to become covered to greater depths. Under ideal conditions they are uncovered by the next series of high tides when they hatch out. During the short period that the eggs are in the beach sands they are preyed upon by beetles and birds. It also has been reported by the California Fish and Game Department that ground squirrels have made diggings along the same contour levels as the eggs are found; one squirrel was found to have over 400 grunion eggs in its stomach. Thus, even though the grunion protects its eggs from numerous predators in the sea it does not conceal them well enough to be safe from some terrestrial enemies.
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	Q&A 4.	In a pasture near my home, there is a hollow in which rain accumulates for several months of the year: Although it has no connection to any other body of water, the newly formed pond is quickly populated by small minnowlike fish that persist until it dries up. Where do these fish come from? Houston, Texas
	Fishes that appear in temporary ponds and water stands are generally silversides (Atherinidae) and killifishes (Cyprinodontidae). Some of the fishes in these families produce eggs with sticky trailers that adhere to water birds. The birds then carry the eggs to isolated ponds. These fishes have very rapid life cycles and can become abundant in only a few weeks time.
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	Rosenstiel School of Marine & Atmospheric Science Library University of Miami, FL USA 4600 Rickenbacker Causeway, Miami, Florida 33149 Phone: 305 421 4060 Fax: 305 421 9306 E-mail: libcirc@rsmas.miami.edu		go to the top