Sand raking disturbs grunion eggs during their delicate incubation period.
The grunions' behaviour must give them some survival advantage.
There are no good counts of the grunion population.
At new and full moons during the summer, grunion emerge from the ocean to spawn on the beach.
The normal lifespan of the grunion is three to four years, although individuals up to five years old have been found.
Seagulls, sea lions, and sand sharks have also been observed feeding on grunion during a grunion run.
Many people enjoy catching grunion at events called grunion runs.
In a laboratory setting, grunion eat live brine shrimp.
