Taxa List

Crustaceans
Copepods

Small planktonic crustaceans, adult size from ~ 0.2 mm to 10 mm.  Ubiquitous. [N.B. >250 species are reported
from the California Current System, only a few of which are illustrated here.]

Euphausiids

Pelagic shrimp-like crustaceans with exposed gills, well-developed eyes; most species have 10 photophores.  Adults of local species are smaller than 30 mm.

Mysids

Shrimp-like crustaceans with spherically shaped statocysts (balance organs) on the uropods (tail fan).

Decapods

True shrimps, and larvae of lobsters and crabs.  The eyes are often stalked and the gills are always covered by the carapace.  The larval phase is planktonic while the adults may be planktonic or benthic.

Hyperiid Amphipods

Small crustaceans (2-42 mm) with large, compound eyes; some species associated with gelatinous zooplankton.

Ostracods

Small crustaceans (0.5-6.0 mm) with a bean-shaped bivalved carapace, commonly known as "mussel or seed shrimps."

Transparent or Jelly-Like
Cladocerans

Commonly called "water fleas."  Bear a large, anterior compound eye, and carapace covering most of the body.

Ctenophores

Transparent marine animals with eight rows of cilia.  Body is ~97% water, size from a few mm to several cm.

Jellyfish

Often transparent, bell-shaped marine animals with hanging tentacles; body more than 95% water; size varies.

Pelagic Tunicates

Nearly transparent marine animals, body mostly water.  Four pelagic groups: salps, doliolids, appendicularians, and pyrosomes; each is covered by a thin or thick tunic.  

Siphonophores

These are colonial animals, mostly transparent, with many specialized parts; relatives of jellyfish. A pneumatophore is a gas-filled float positioned at the top of the colony in some siphonophores. 

Worm-Like
Chaetognaths

Nearly transparent, flattened worm-like animals with side fins and tail fins; adults ~ 2 - 120 mm. Commonly referred to as "Arrow Worms."

Segmented Pelagic Worms

Segmented worms with well developed, paired, paddle-like appendages.

Animals with Shells
Heteropods

Molluscs with reduced shells, medial swimming fin, well developed eyes and a nearly transparent body; size to 300 mm.

Janthina

Small to medium-sized pelagic sea snails, commonly known as purple snails or violet shells. These snails live at sea-air interface.

Pteropods

Small, swimming pelagic snails, commonly known as "sea butterflies."

Squid
Squid

Cephalopods with eight arms and two tentacles, body often covered with chromatophores (pigment cells).

Others
Fish eggs and larvae

The planktonic stages of some common local fish, often not bearing any likeness to the adults.

Invertebrate larvae

Meroplankton:  planktonic stages of local species that are often benthic as adults.