202 UNDERWATER GUIDE TO MARINE LIFE 



Distrihution: Carolinas to Cape Cod. Rarely to Nova Scotia. 



Identification: The size is rather large (for a sea horse), and the color is 

 brownish over all. 



Habits: This is a slow-moving fish, most often seen anchored to eelgrass 

 or other objects with the prehensile tail. The dorsal fin is the principal organ of 

 propulsion. The earlike pectorals also help, but these fishes are not very mobile. 

 Because of this, the swim bladder is large and well developed, and if a little 

 gas is removed from it, the fish will sink to the bottom (Gudger, 1905). 



By means of stroboscopic lights and a high-speed camera, Breder and Edgerton 

 (1942) found that the dorsal fin movement is very complex and fast. The fin 

 moves from side to side thirty-five times a second, nearly as fast as a humming- 

 bird's wing. There are also wavelike motions in this fin passing from the top 

 to the bottom, ten waves passing through this fin in a second. This locomotor 

 method, as well as the habit of living in seaweed, limits sea horses to a small 

 size. It is probably not coincidence that the largest sea horse lives where there 

 are the largest seaweeds. Movements of the head and, thus, the pectoral fins, 

 change the direction of travel. 



Similar Species: The giant sea horse, Hippocam-pus ignens, of Magdalena Bay in 

 Baja California and southward, grows to 1 foot long and is the largest sea horse. 



Spiny-Rayed Fishes: Order Acanthopterygi {"spiny fins") 



The great majority and the most varied of fishes belong in this group. The 

 great array of species presents difficult problems in identification because of the 

 similarities in appearance between species as well as the variations of color 

 and pattern within many of them. Nevertheless, this cannot help but be a 

 fascinating group, as well as a challenging one, because the most colorful of all 

 fishes, as well as those with the most complex and interesting social behavior, 

 are found here. 



All spiny-rayed fishes have at least one, and usually all, of the following 

 characteristics: (1) spines on the forward ends of the pectoral and \'entral 

 fins, (2) the pectorals placed high on the body above the abdomen, (3) the 

 possession of two dorsal fins, one spiny and one soft, and (4) ventral pins placed 

 under the pectorals. 



There are several large suborders. These are the dominant fishes of todav. 



Mulletlike Fishes: Suborder Percesoces 



These are the only spiny-rayed fishes that still have the ventral fins placed on 

 the abdomen in back of the pectoral fins. Their bodies are rather elongate. There 

 is a small, spiny dorsal fin widely separated from the soft dorsal. The three 

 families of this suborder constitute the most primitive of all spiny-raved fishes. 

 They are typical of the warm temperate and tropical seas of the world. 



SILVERSIDES: Family Antherinidac 



These small fishes, also known as "smelts," "whitebait," and "frv," school 

 by the thousands and look much like anchovies or small smelts, but these latter 

 do not have two dorsal fins. Silversides have a brilliant silver stripe on the 



