of the Fishery Board for Scotland. 



209 



experiments of Mobius, that, although the average size of the ova in eels of 

 52 cm., and more, is greater in autumn than during the rest of the year, 

 still even in autumn eels are found having ova much smaller than the 

 average size of ova during that season, and in other months of the year 

 ova are found of as great a diameter as those observed in autumn. Mobius 

 found no spermatozoa in the testes of the eels kept in the aquarium. In 

 the migrating eel, when it has been examined, the ovaries are in a very 

 undeveloped condition. Eels which have been caught in salt water have 

 not shown much, if any, further tendency to ripeness of the ova. Whether 

 the eels captured in salt water were eels which had migrated during the 

 autumn is not known. These may have been eels which are found dur- 

 ing summer near the shore in salt water. An interesting question suggests 

 itself — What becomes, in the winter months, of the eels of all sizes which 

 are found during the greater part of the year in the estuaries of rivers ? 

 Whether they join the body of migrating eels, and proceed to the sea, or 

 whether they, as some think, burrow into the mud during cold weather 

 remains to be solved. The eel which is commonly caught in the estuary 

 of the Eden during the summer is the yellow variety of eel. Before the 

 second week in May, the eels which are captured there are only about 

 12 inches in length. On and after that date, however, it is observed that 

 larger eels, about 20 inches long, come up the river with the flood tide, 

 and go down again with the ebb. In the month of July large eels come 

 up from the sea, and proceed right up the river into the fresh water. 

 These eels are about the size of the migrating eel, and are accompanied by 

 small eels. With the cold weather, at the beginning of winter, the eel- 

 fishing on the Eden ceases ; none but very small eels are then caught. 

 The eel fishermen are of the opinion that the eels burrow into the mud in 

 the bed of the estuary, and become dormant during winter. This belief 

 is to some extent corroborated by the fact that occasionally during winter 

 the musselmen on the Eden bring up small eels among the mussels and 

 mud in the mussel rake. On February 25th, 1895, two eels measuring 

 11 J and 12J inches respectively were captured in this manner. They 

 were both females having ova which measured '045 mm. in diameter. It 

 is only during winter that eels are procured with the rake, and they are 

 all small, viz., under 18 inches in length. In summer they sometimes 

 bring up eels in the rake, but they always escape at the surface of the 

 water. This fact seems to point to the probability that certain of the eels 

 do hibernate, but perhaps only those eels which are immature do so, while 

 the larger estuary eels proceed to the sea. No eels are caught in winter 

 by means of the ' tot,' * which is used with success in summer. The fisher- 

 men are of the opinion that if the eels were in the river, they would be 

 able to catch them by this method. If the eels hibernate, the same non- 

 success would attend the efforts of the fishermen as if the eels left the 

 estuary altogether. That they do not all leave is proved by the capture 

 of certain individuals, and the latter appear to be in a semi-dormant con- 

 dition, for they could, without the slightest difficulty, escape between the 

 prongs of the rake. During the summer, eels of various sizes, from 10 

 inches to 2 feet or more in length, are quite common in the salt water 

 pools among the rocks near St Andrews. In May of this year (1895), the 

 rock pools were carefully examined, on several occasions, at low water 

 during spring tides. Two eels only, measuring 10 inches in length, were 

 obtained, while one which appeared to be less than 18 inches long was 

 seen. The larger eels, which are to be seen there in summer, were absent. 



* The so-called ' tot ' is composed of a number of sand-worms (Arenicolee), which 

 are threaded on worsted and rolled up into a ball. The teeth of the eel are caught 

 iu the worsted, and it is then easily lifted into the boat. This method of fishing is 

 also known as ' bobbing.' 



