BREEDING PLACES OF THE EEL SCHMIDT 313 



important fisheries about October. In the -western part of the Eng- 

 lish Channel trawlers may, toward the end of the year, occasionally 

 bring up a few big specimens in their nets, but after this the last 

 trace of the eel on European ground is lost. No longer subject to 

 pursuit by man, hosts of eels from the most distant corners of our 

 continent can now shaj)e their course southwest across the ocean, 

 as their ancestors for unnumbered generations have done before 

 them. How long the journey lasts we can not say, but we laiow 

 now the destination sought : A certain area situate in the w^estern 

 Atlantic, northeast and north of the West Indies. Here lie the 

 breeding grounds of the eel (fig. 6). 



Spawning commences in early spring, lasting to well on in sum- 

 mer. The tiny larvse, 7-15 mm. long, float in water layers about 

 200-300 meters from the surface, in a temperature of about 20° C. 

 The larvae groAv rapidly during their first months, and in their 

 first summer average about 25 mm. in length (fig. 11). They now 

 move up into the uppermost water layers, the great majority being 

 found between 50 and 25 meters or at times even at the surface 

 itself. Then they commence their journey toward the shores of 

 Europe, aided by the eastward movement of the surface water 

 itself. During their first summer they are to be found in the west- 

 ern Atlantic (west of 60° long. W.). By their second summer they 

 have attained an average length of 50-60 mm., and the bulk are 

 now in the central Atlantic. By the third summer they have ar- 

 rived off the coastal banks of Europe and are now full grown, 

 averaging about 75 mm. in length, but still retaining the com- 

 pressed, leaf-shaped larval form. In the course of the autumn 

 and winter they undergo the retrograde metamorphosis which gives 

 them their shape as eels and brings them to the elver stage, in which 

 they move in to the shores and make their way up rivers and water- 

 courses everywhere (Plate 3). The average age of the elvers in 

 spring is about 3 years. Many individuals, especially males, keep 

 to the brackish water in lagoons or estuaries; others, especially fe- 

 males, move far up the streams they have entered and may in the 

 course of their wanderings penetrate far into the interior of the 

 Continent. In Switzerland, for instance, considerable quantities of 

 eels occur, and specimens have been taken there in waters at an 

 altitude of 3,000 feet above the level of the sea. The eels utilize 

 their sojourn in fresh water to feed and grow big, but the duration 

 of their stay here varies greatly, according to sex, climate, and 

 quantity of food, ranging from about five to about twenty years or 

 more. All the large eels are females ; the males seldom exceed 45 cm. 

 in length. During its period of growth the eel is of a yellowish 

 or greenish color, with no metallic luster; these grooving eels are 

 generally termed " yellow eels." When they have reached the stage 



