IUCN threat status:

Least Concern (LC)

Comprehensive Description

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  Common names: halfmoon (English), chopa (Espanol)
Medialuna californiensis (Steindachner, 1876)

California halfmoon

Body an elongate oval, compressed;  small pointed head; mouth is small, horizontal and opens at the front; the top jawbone slips partially under the under-eye bone when the mouth is closed; teeth pointed, 1 row on each jaw; dorsal fin continuous, IX-XI spines that fold down into a scaly groove, 22-27 rays, spiny part much lower than soft part; anal III, 17-21;  tail fin slightly concave; paired fins are relatively short; origin of the pelvics behind the base of the pectoral fin; scales small, thick and rough, covering the body, head (except forward of eyes) and soft portions of the median fins.

Dark bluish above, paler below; sometimes indistinct short bars along flank; a dark blotch at upper corner of operculum; dorsal, tail and anal grey, dark outer margins; juveniles blue above, silvery below.

Size: 48.3 cm.

Habitat: rocky bottoms and algal beds.

Depth: 0-44 m.

Canada to the SW Gulf of California.   


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© Shorefishes of the tropical eastern Pacific online information system. www.stri.org/sftep

Source: Shorefishes of the Tropical Eastern Pacific Online Information System

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