Halfmoon Medialuna californiensis

Type of Animal:
Sea Chub

High water/mid-water column areas-over rocks, mid-depth areas over kelp, rocky reefs, kelp beds, floating kelp pads, oil rigs, shallow rocky areas, kelp forests

E Pacific from Vancouver Island to Gulf of California

Elongate compressed oval fish w/ small pointed head, small horizontal mouth, gray to dark bluish gray, fish darker in more offshore areas, juveniles blue above & silvery below, caudal/tail fin resembles crescent moon, dark spot above gill opening

Kelp, red algae, green algae, small sponges, shrimp, small anemones, mussels, small crabs, squid, anchovies, sardines

Status in Wild:

Not applicable

Schools of 12-200 fish

Additional Info:

Young: Fry
Group: School
2 lbs

1-2 days 

Life Span:
4-8 years

Body Length:
Adult: 10-12 in
Young: 1 in

Main predators are pinnipeds, larger fish, & fish-eating birds.
Also called blue perch, Catalina blue perch, California halfmoon, blue bass, black perch, island mackerel, blooper, blue wizard, halfmoon perch, medialuna, & chopa medialuna.
Often found schooling w/ other fish species.
They’re broadcast spawners, w/ sperm & eggs being released into water column.
Spawning season runs from June to October.
Eggs/newly hatched larvae are planktonic.
Reach maturity at a year old.
From a distance, coloration allows them to blend in w/ surrounding area.
Dark spot above gill opening may function as false eye-spot, distracting/confusing predators.
Scales are small/thick/rough.

Fun Fact(s):
They can be rather scrappy when hooked.
These fish often disliked by kelp growers due to feeding on kelp.
Get name from half-moon shaped tail.
Very popular game fish in California w/ fishing season running from August-April. They’re also very common bycatch.
Largest fish on record measured 1.583 ft & weighed 4 pounds, 12.5 ounces.
Meat said to have light mild flavor.

Leave a Reply

Your email address will not be published. Required fields are marked *