246 UNDERWATER GUIDE TO MARINE LIFE 



Identification: The usual intense silvery color of mojarras is crossed by dusky 

 bands, which are more evident in young fish. 



Habits: This little fish swims actively in shallow water, usually over a sandy 

 bottom. It is omnivorous and schooling. 



Similar Species: The mojarra, Eucinostomus calif ornien sis, reaches 8 inches 

 and is common in bays from Cape San Lucas to Panama. The common mojarra, 

 Eucinostomus gula, reaches 6 inches and ranges from Cape Hatteras to Brazil. 

 Both of these lack the crossbanding of the gray mojarra, though indistinct 

 blotches may be present. 



RUDDERFISHES: Family Kyphosidae 



Rudderfishes received their name from their habit of following in the wake 

 of boats. They have incisor teeth in the front of the small mouth but have no 

 molars. This befits their algae-eating habits. They also eat some small inverte- 

 brates. The body is spindle-shaped, and the dorsal and anal fins are long and low. 

 There are not many species, but their distribution is world-wide, chiefly in the 

 tropics. Small pods or large schools of them mill about rocks grazing on algae, 

 depending upon alertness and speed for protection. 



BERMUDA CHUB (chopa) : Kyphosus sectatrix^Colov Plate 8 



Size: Averages 1 foot or more. 



Weight: Up to 20 pounds. 



Distribiition: From the West Indies north to Florida. Straggles to Cape Cod. 



Identification: The ground color is slaty. There are thin, dull yellow, horizontal 

 stripes, and there is a color phase which has large light spots on the back and 

 sides. The color becomes darker when the fish swims under coral ledges or in 

 holes. 



Habits: This is an active and curious fish. It swims chieflv in reef waters that 

 have access to the open sea and will follow ships long distances out to sea, 

 probably to feed on garbage. Its flesh is very firm and delicious to eat. 



Similar Species: There are several similarly shaped species ranging north to 

 the Canary Islands and on the West Coast from the Gulf of California 

 southward. One of these, the California halfmoon, Mediahina calif ornien sis, 

 is found from southern California to Cedros Island. It has a steely ground color 

 with oblique rows of spots and blackish fins. 



OPALEYE (greenfish): Girella nigricans— Color Plate 8 



Size; Averages 10 inches. Up to 15 inches. 



Distribution: San Francisco to Cape San Lucas. 



Identification: The color is uniform light to dark green. There is a prominent 

 yellowish spot below the spiny dorsal fin on the back. 



Habits: This is an active little inshore fish, speedy and alert, common in 

 shallow, rocky waters where it browses on seaweed. 



CROAKERS: Family Sciaenidae 



This is the last of the complex pcrchlike families, and it is a large one, 

 containing 150 species. Though these species are extremely \'ariable in form, the 

 habitat variation is not extensive. Croakers are conspicuous in warm temperate 



