By Jami Lambert
The words “California’s treasure” can bring many different ideas to mind. Some see the beautiful stretches of beach while others may picture the abundant redwoods or even the promise of gold to new settlers in the 1840s and 50s.
But when Karen Martin, professor of biology at Pepperdine University, says those words, she’s not referring to trees, sandy beaches, or gold. She is talking about grunion, a small slender fish found only in Southern California. And she’s doing her part to ensure the well-being of this rare resource for many generations to come.
“I have been interested in grunion ever since I came to California,” Martin said. “I just think they are a very unique, wonderful animal.”
Martin was recently awarded the California Sea Grant of nearly $10,000 to aid in her research of the effects of beach grooming on the grunion population. The grant will allow her to monitor and observe four San Diego beaches where grunion often lay their eggs.
These fish are remarkable because they are the only fish in existence to spawn out of water. Spawning occurs from March through August, between two and six nights after a full or new moon. The process begins after high tide and continues for several hours.
As a wave breaks on the beach, female grunion swim as far up the slope as possible and use their tails to create a nest in the wet sand. Once they are half buried in the sand, they deposit unfertilized eggs and wait for a male grunion to fertilize them before retreating to the water.
The spawning process usually takes less than 30 seconds and a female lays between 1,600 and 3,600 eggs and can spawn as many as six times during a season. The eggs incubate in the sand for 10-15 days and hatch during the next high tide series.
Last summer, the city of San Diego was confronted with the issue of grunion survival when large tractors and trucks were used to groom the beaches by raking algae from the sand to make them more pleasant to tourists. This heightened public concern and the city’s Parks and Recreation Department took immediate action to end the grooming. Unfortunately, a lack of specific evidence left too many unanswered questions. Martin hopes to find answers to some of these questions.
In addition to beach grooming, erosion, harbor construction and pollution contribute to a loss of spawning. A regulation passed in 1927 established a closed season between April and June, in which grunion could not legally be harvested. The fishery improved and in 1947 the closure was shortened to April through May. This closure is still in effect today to protect grunion during the peak spawning period.
Martin is not alone in her concern for this species of fish. “This has become a great collaborative effort,” she said.
Others involved in the study include Project Pacific, a nonprofit organization dedicated to “actions benefiting the ocean,” the Birch Aquarium at Scripps, the city council of San Diego, the San Diego Parks and Recreations Department, Scripps scientists, Pepperdine University researchers like students Rachel Pommerening and Tara Spear and numerous volunteers.
Since no significant research on the grunion has been done since the 1940s, it is not clear whether the grunion is an endangered species.
They are difficult fish to locate and study in open water and are not kept well in captivity. Martin will begin collecting data in March and she hopes to have some results by the end of the summer.
Photo by Jennifer Flannery
TEAM GRUNION: The research of Karen Martin, Rachel Pommerening and Tara Spears may save grunion.
March 21, 2002