Grunion Run, Birch Aquarium at Scripps Institution of Oceanography in San Diego, California
The History of Grunion.
From Point Conception in California to Point Abreojos in Baja Mexico grunion are only found in the Pacific Ocean off the coast of California and Mexico. Grunion are found between San Francisco in Northern California to San Juanico Bay in Baja, Mexico to the south.
Archaeological evidence, such as bones, found that Coastal Indians in California first harvested grunion. Spanish explorer, Juan Cabrillo, mentioned grunion in his ships log dating back to 1542. In 1860 scientists in San Francisco Bay officially identified grunion.
Grunion are two fish species. The California Grunion species is called L. tenuis and the Gulf Grunion species is called L. sardinas. They are in the Silversides family including the jacksmelt and topsmelt family.
Grunion are small, slender, sardine sized fish and have bluish green backs and silvery sides and bellies with blunt, rounded, snouts. They are very slippery and hard to hold onto when caught by hand.
Grunion have very unusual mating rituals they are known for. At very high tides male scouts wash up on the beach when a big wave breaks. The females wash up on the beach behind the males when its all clear with the next big wave.
The females swim up onto the sand as far as possible. Then she digs into the sand with her tail by arching and twisting her body, buries herself up to her fins, and lays her eggs about four inches below the sand surface.
Several males wrap themselves around the female and fertilize the eggs with milt. The next big wave washes the grunion back out to sea, leaving the eggs buried in the sand to incubate and hatch.
Kept moist by the ocean water the eggs incubate for about 10 days. If the eggs are not eaten by shore birds or other predators, at the next high tide the eggs hatch with the agitation of the rising surf and the young grunion are washed out to sea to begin a new generation.
By the time grunion are one year old they are about five inches long and ready to spawn. Adults range in size from 6 to 7 inches. The biggest grunion reportedly on record was 8.5 inches long and found in La Jolla, Ca.
Grunion growth rates slow and then stop during spawning season. Peak spawning season is March - June. An adult female can lay anywhere from 1600 - 3,000 eggs at a time.
A grunion's life span is three to four years. Grunion have no teeth, feed on organisms such as plankton, and are non-migratory.
By the 1920’s recreational fishing for grunion caused signs of depletion. Regulation in 1927 & 1947 closed the hunting season during peak spawning.
Other regulations such as grunion can only be caught by hand, only on specific dates, and, while there is no limit, you may only take what you can use have helped replenish the population. With regulation of existing laws and appropriate harvesting, the grunion population is maintaining itself.
Concentration here in Southern California is very large. However, grunion are not an abundant species. Beach erosion, pollution, and harbor construction have further reduced grunion spawning habitat. This is a critical problem facing the grunion population.
Grunion runs at Birch Aquarium run April - June. Become a Grunion Greeter!
You need a fishing license to catch grunion. Take it with you unless you are only observing.
Wear layered, warm clothing and some kind of waterproof shoe, like rain boots, that will keep your feet dry as you will get wet..
Take a flash light, snack, and a blanket or chairs. You will have to wait awhile.
There are plenty of great hiking trails in the area and surrounding San Diego County.
Are we there yet? What to take on a road trip:
An ice chest with food, snacks and drinks for everyone. Forget sharing.
Don't forget your chargers, headphones, earplugs, meds, and a bag for garbage
Take along your Kindle and cell phone to keep yourself and the kids occupied on long road trips. Down load any e-books and apps that will help you.
Remember to take along a great camera. We found the Sony Nex-5 to be light weight and user friendly.
Freeways, streets, and traffic jams are frustrating. Take a good GPS system with you and visit off season.
How to cook um.
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