MASTERS OF THE WATER-BONY FISHES 191 



an isolated group, their origin and evolution being a mystery. They are found 

 in most temperate and all tropical seas. Bertin (1942) gives a detailed account 

 of eels. 



COMMON EELS: Family Anquillidae 



These most primitive eels are recognized by the presence of small scales 

 imbedded in the skin and the large pectoral fins. They are really fresh-water 

 fishes, which, opposite to the salmon, enter salt water to breed (a situation 

 described as "catadromous"). Members of this family are practically world-wide, 

 but are not found on our Pacific coast. 



COMMON eel: Anquilla rostrata— Color Plate 1 



Size: Averages 2 feet. Exceptionallv up to 5 feet. The females are larger. 



Weight: Averages 1 pound. Exceptionally up to 7 pounds. 



Distribution: St. Lawrence River to Brazil. A very similar species on the 

 Atlantic coast of Europe. 



Identification: The color varies from brown to black and is usually olivaceous. 



Habits: The story of the common eel is one of the most remarkable known, 

 both from the standpoint of the history of scientific speculation and that of 

 animal adaptation. Ley (1951) tells it in excellent fashion and in some detail. 



The story revolves around the eel's extraordinary reproductive habits which 

 from earliest times were shrouded in mystery. Aristotle said that "the eel has 

 no sex, no eggs, no semen, and originates from the the entrails of the sea." Such 

 a statement could have been made because fishermen had never found roe or 

 milt in eels which they captured. Up until 1777 various explanations of eel 

 reproduction were given: they generated from slime from other eel's bodies, 

 from bits of hair, or from sod wet with May dew. In that year a man named 

 Mondini found what he believed were female sex organs (ovaries), but it 

 was not until 1824 that Syrski found comparable male organs. Then in 1895 

 Grassi and Calondruccio kept what they believed to be an entirely different 

 animal called "leptocephalus," a bandlike, transparent fish of up to 3 inches 

 in length, in a tank and observed that these animals (which were actually larvae) 

 shrank, became slimmer, and then transformed into baby eels or elvers. It was 

 these two men that brought forth the theory that eels are in the rivers only 

 to grow and mature and go to the sea to breed. Where and when eels breed was 

 not known until a Dane named Johannes Schmidt, with the help of the fisher- 

 men he had supplied with deep nets, observed that the nearer to the Sargasso 

 Sea that leptocephalus larvae were caught, the smaller they were. This was 

 in 1904, and in 1913 Schmidt went to the Sargasso Sea and found the tiniest, 

 most recently hatched leptocephalus of all. The mystery was solved. Eels leave 

 the streams in the fall and travel the Gulf Stream to the Sargasso Sea to 

 deposit their eggs, one of the most remarkable of all fish migrations. 



No less remarkable is the trek the larvae make back to the streams. European 

 larvae take three years to travel the three thousand miles, and American 

 eels, having the shorter distance of one thousand miles to go, take only a year. 

 The larvae grow to 3 inches in this time. When they enter fresh water, they 

 become slim, transparent, "glass eels" and soon thereafter darken to miniatures 

 of the adults. These young may be extremely plentiful, seeming to clog streams 



