208 UNDERWATER GUIDE TO MARINE LIFE 



Identification: The ground color varies somewhat with the environment, but 

 the three or four large dark blotches on each side are the best identifying 

 mark. The most common ground color is white to rose. Red specimens are 

 sometimes seen. 



Habits: This fish is usually found swimming singly or with other reef fish 

 such as small parrot fishes. It feeds in sand near coral heads. 



Similar S'pecies: The northern goatfish, Mullus auratus, is another West 

 Indian sandy bottom fish, but it strays north to Cape Cod. It is red above with 

 light yellow sides and with two rows of light blue spots on the sides above 

 the lateral line. 



The yellow goatfish (^color fhotografVi), U^eneus martiniciis, differs from 

 most of the goatfishes in that it schools densely and acts much like the 

 smaller schooling grunts in habits. There is a bright yellow stripe extending 

 horizontally from the eye, down the middle of the pale, whitish body, and onto 

 the tail. This coloration thus strongly resembles that of the yellowtail snapper 

 COcyurus^. 



The only common West Coast goatfish is Upeneiis dentattis. It occurs from 

 Cape San Lucas southward. It is rosy with a red stripe running down the side 

 and onto the tail fin. 



Mackerellike Fishes: Suborder Scombroidei 



These primarily oceanic fishes are mainly offshore predators and are so 

 diverse, numerous, and confusing that we will be able to treat them onlv in a 

 summary way. They are mostly rather large, schooling fishes of the open seas 

 and as such are difficult for the swimmer to observe. Nevertheless, the oppor- 

 tunity to study them under water should be grasped because little is known 

 about most of them. In general, they have smooth, streamlined bodies that offer 

 little resistance to the water. They have pointed heads, constricted caudal 

 peduncles, and large lunate tails. These are all adaptions for swift movement. 

 It is in this group that we find the swiftest of fishes as well as the swiftest things 

 that swim. Some of them even have slots into which the dorsal and pectoral 

 fins fold in order to further reduce water resistance. The typical families of the 

 group have separate spinv and soft dorsal fins, and the soft dorsal and the anal 

 fins are of similar size and shape, being directly over and under each other. 

 Most of them are highly predacious, and many are schooling. The color is 

 usually silvery with a greenish or bluish back. As we shall see, there are a 

 number of families which seem to fit none of these rules. The most constant 

 features are the silvery, iridescent ground color and the similar soft dorsal and 

 anal fins, but even these rules are frequently broken. 



TRUE MACKERELS: Family Scombridae 



The swimmer will not often encounter the largest of the species of this family, 

 but if he does he is in for an almost unmatchable thrill because of the speed, 

 size, and silvery beauty of these fishes. There are about sixty very similar 

 species in the world of these mostly predacious fishes. Many of them are 

 cosmopolitan, of great size, and commcrciallv xaluable. All are schooling and of 

 wide distribution. 



