Leuresthes tenuis (California Grunion)
Credit: Donna Stern
about the species
California grunion are known for their spectacular spawning runs onto sandy beaches in the middle of the night. This endemic planktivorous fish lives in coastal waters from Punto Abreojos, Mexico, to Tomales Bay, California, spawning in the spring and summer after full and new moons. Eggs remain buried in sand above the water line throughout incubation, and are only triggered to hatch when washed out to sea. Anthropogenic impacts include many beach activities in the critical reproductive habitat, as well as a unique bare-hand fishery on the spawning fish.
why species was selected
A range shift since 2002 has L. tenuis spawning as far north as Tomales Bay, well north of the historic range south of Point Conception. However, these extralimital fish are smaller, shorter lived, and produce fewer offspring than those on the southern coast. Thus, potential for adaptive response to climate change is unclear. L. tenuis serves as key indicator species for sandy beaches in California’s Marine Protected Areas and for Ventura County’s climate change initiative.
