Grunions

Grunions are small, slender fish of the genus Leuresthes, native to the Pacific coast of North America. They are famous for their unique spawning behavior, which occurs on beaches during specific high tides, typically a few nights after a new or full moon. These tides are known as "grunion runs."

During a grunion run, female grunion swim ashore and burrow into the wet sand to lay their eggs. Male grunion then wrap around the females and fertilize the eggs. The fish then ride the receding wave back into the ocean. The eggs remain buried in the sand, protected from predators and drying out, until the next series of high tides, approximately two weeks later. The vibrations of the incoming tide trigger the hatching of the eggs, and the newly hatched larvae are washed out to sea.

This remarkable reproductive strategy has made grunion a subject of scientific interest and a popular spectacle for observers along the California and Baja California coastlines. Regulations are in place to protect grunion populations, including fishing seasons and size limits. Their dependence on specific tidal conditions makes them particularly vulnerable to environmental changes and coastal development.