Southern California’s beaches are set to witness another round of the rare and fascinating grunion runs, where small, silvery fish emerge from the ocean to spawn onshore. The phenomenon, tied to lunar cycles, occurs during specific nights from March to August, with the next run expected to begin tonight and continue through Friday.
Core Facts & Immediate Action
- When and Where: The grunion runs are predicted to occur from Tuesday to Friday, with the best viewing typically on the second and third nights. The fish emerge for about two hours as the high tide recedes, usually between 10 p.m. and 2 a.m.
- Key Locations: While grunion runs happen across Southern California, Cabrillo Beach in San Pedro is a well-documented hotspot. The timing varies slightly by location, with runs occurring earlier in San Diego and later in Santa Barbara.
Deeper Dive & Context
The Spawning Ritual
The grunion’s mating process is unique. Females bury themselves halfway in the sand, laying eggs while males wrap around them to fertilize them. This behavior, known as a "grunion run," is a rare spectacle visible to the public. The eggs incubate in the sand before hatching over a week later.
Viewing Tips
- Best Nights: The second and third nights of the four-night runs tend to be the most active.
- Safety & Accessibility: The California Department of Fish and Wildlife (CDFW) advises checking with local lifeguards for real-time updates, as conditions vary. Some beaches may have curfews or safety restrictions.
Regulations & Public Participation
While observing the grunion runs is permitted, there are rules for those who wish to collect the fish. The CDFW allows limited harvesting under specific conditions, though exact regulations vary by location. The agency emphasizes responsible viewing to minimize disturbance to the natural process.
Scientific Uncertainties
Despite decades of observation, scientists still don’t fully understand why grunion runs occur at slightly different times along the coast. CDFW environmental scientist Malcolm Tunnell notes that the fish remain a "cryptic species," with behaviors that vary unpredictably.
Public Engagement
For many Southern California families, witnessing the grunion runs is a cherished tradition. Reports of sightings have been documented from La Jolla to Ventura, with enthusiasts encouraged to share their observations with local authorities.
Upcoming Runs
The next predicted run after this week is expected on July 14–17, with specific times adjusted for each night. The CDFW provides a schedule based on moon cycles and historical data, though exact timings can shift slightly.