302 THE MIGRATION OF THE ANCHOVY. 
summer is only obtained further south on the French coast, where 
anchovies are taken in summer, and where they probably spawn. 
We know that there are anchovies in autumn and winter at the 
western end of the English Channel; these, in order to reach a 
temperature high enough for spawning, must go either north or 
south. It seems probable that all these anchovies come from 
Holland and return thither. 
In relation to this probable migration it is interesting to compare 
the statistics of the Dutch fishery with the evidence we have 
obtained of the varying abundance of anchovies in the neighbour- 
hood of Plymouth. The following are the temperatures in July 
in the Zuyder Zee, and the total yield of the anchovy fishery in 
that sea in successive years : 
Temperature in July. Ankers of Anchovies salted. 
1882 , TACT atollony : 18,736 
1889 : 16°8° to 18°9° ; 1,676 
1890 : 15°4° to 18°3° : 194,096 
1891 : 16:82 folio. ; 45,914 
1892 : 16:2° to 17°7° 6,854. 
1893 evade cones ; 13,908 
Now we first heard of anchovies in connection with the M. B. A. 
in November, 1889, when large numbers were seen at Dover, large 
numbers were taken in the sprat seines at Torquay, and samples 
were brought to the Laboratory by the pilchard fishers at Plymouth. 
In the previous summer very few had been caught in the Zuyder 
Zee, although the temperature in that summer was high. But in 
the following summer, with a similar temperature in the Zuyder 
Zee, one of the maximum catches was made there. In the winter 
of 1890 anchovies were abundant in the Channel; I obtained 
1000 from pilchard-nets in two days in November, and again in the 
following summer a fairly large catch was made in the Zuyder Zee. 
In the winter of 1891 and 1892 anchovies were not plentiful off 
Plymouth, and in the following summers the catch in the Zuyder 
Zee was small. 
The fact that so few anchovies were taken in the Zuyder Zee in 
1889, while in the following autumn they were so abundant in the 
Channel, is difficult to reconcile with the theory that the winter 
anchovies in the Channel come from the coast of Holland. It is 
possible that there is another explanation, namely, that in warm 
winters the anchovies come northward to the Channel, and in a 
warm summer following pass up to the warm waters of the Dutch 
coast, where they are crowded together in narrow waters, and so 
give opportunity for a fishery, If this suggestion were correct the 
prosperity of the Zuyder Zee fishery would depend not, as Prof, 
