Common name: Copepods

Scientific name: many different vernal pool species, most without name
Phylum: Arthropoda
Subphylum: Crustacea
Class: Copepoda
Habitat: vernal pools, lakes, ponds, oceans

Size: up to 3 mm long

Description: There are many different species of Copepods. Few of the species in vernal pools have been named. You are most likely to spot the bright red Diaptomus and at least one green copepod species in Sacramento’s vernal pools. Copepods have four or six legs, a short tail, and long antennae.

Fun facts: The cysts of Copepods can survive on the bottom of a vernal pool for a long time. When scientists found Copepod cysts that were 300 years old, they put them in water and watched them hatch!

Life cycle: Copepods can reproduce in two ways: male and female Copepods can mate or female Copepods can produce cysts without the help of a male. The female carries the cysts in sacs near the base of her abdomen. When she lays her cysts, they fall to the bottom of the vernal pool. Some of the cysts will hatch right away and the young Copepods will grow quickly. The first stage of a Copepod’s life is spent as a larva. The larva looks very different from the adult Copepod. When the larva is fully grown, it will metamorphose into the adult form.

There may be time for several generations to reproduce before the vernal pool dries up. The other cysts can wait in the bottom of the pool for many years before hatching. When the pool dries up, the cysts remain buried in the hot, dry bottom waiting for the return of winter rains.

Ecology: Some copepods eat detritus, Bacteria, and Algae. Others, like the red Diaptomas, are predators that eat tiny Water Fleas, Seed Shrimp and other species of Copepods. In vernal pools, copepods are eaten by Vernal Pool Tadpole Shrimp, Flatworms, Aquatic Beetle larvae and other aquatic insect larvae, wading birds, Mallards and other ducks that filter them out of the water with their bills.

Investigate: When you visit a vernal pool, watch how the Copepods move through the water. What part of their bodies do they use to swim? How do their jerky movements help them to avoid predators?