SCIENCE AND THE SEA FISHERIES 237 



the North of Spain. They were also taken to the westward up to 

 15° W. Longitude, where the depth is 4000 metres and more. Eel 

 larvae are true pelagic forms, they are not found on the sea bottom, 

 but only in the upper layers of water. At night they swim at the 

 surface, in the daytime at depths of from 50 to 100 metres. The 

 greatest number of larvae taken in a single haul of the net was 70, 

 at a depth of 70 metres in 49°25' N. and i2°2o' W., where the depth 

 of the sea is from 1270 to 1310 metres. AH the eel larvae taken in 

 May and June were in a very eaily stage of development ; it was 

 only in September that a search for successive stages in the larval 

 development was successful. 



It is interesting to note that the later stages were captured nearer 

 the coast. In the course of its metamorphosis the breadth of body 

 of the eel larva diminishes, the eyes become a little smaller, the 

 larval teeth disappear, the gut shortens, and gradually the eel-like 

 appearance develops. 



At first the young eel is transparent, the so-called Glass-eel stage. 

 In the Baltic this stage is unknown, but in West Europe, in Great 

 Biitain, France and Spain it occurs in overwhelming numbers, and 

 in many localities is the occasion of a regular fishery. 



M. Vaillant, of the Paris museum of Natural History, has described 

 this fishery on the Atlantic coast of France and there are other 

 descriptions for the south of England and Spain. All agree in 

 describing the enormous swarms of young eels and the brief duration 

 ot the fishery. The young eel now passes into a dark colomed 

 condition, the so-called Montee. The nearer the coast is to the 

 looo-metre line the earlier the eels appear, and naturally at an 

 earlier stage ot their development. On the north coast ot Spain, 

 at Santander, Bilbao and San Sebastian ; in Bayonne in the south 

 of France, the Glass-eels appear from October to December ; in 

 France at Pauillac, Rochefort and Marans, which lie in the estuary 

 of the Gironde and Charente, and in Ireland at Castlemaine, Tralee 

 and Limerick, the fishery commences in January ; in France at 

 Nantes, Dinan and Caen, on the coasts of Brittany and Normandy, 

 as well as in the English Rivers Parret and Severn, it begins in 

 February and March. 



By the time the young eels have worked their way through the 

 North Sea they have for the most part passed through the Glass-eel 

 stage, and have taken on a dark appearance (the Montee). A few 

 Glass-eel larvae have, however, been obtained in the sea off the 

 Danish coast, but never in the Baltic. Here the stage is the Montee. 



All the ascertained facts tend to show that the ripe fresh water 

 eel is a deep sea fish, spawning out in the open Atlantic. The larvae 

 migrate to the rivers ot Western Europe, where they live until 



