RATE OF GROWTH OF SOME SEA FISHES. 



257 



Engraulis encrasicholus, the Anchovy. 



Tlie Dutch iclithyologist, C. K. Hoffmann,* when investigating 

 the anchovy in the Zuyder Zee, captured a number of the young of 

 this species at short intervals in August, September, and October. 

 Their numbers and sizes were as follows : 



Hoffmann proceeds to state that the average length of the sexually 

 mature spawning anchovy is 15 cm., but ripe specimens of only 

 13*0 to 13'5 cm. are not altogether rare. The conclusion which he 

 draws from his observations, and which he emphasises by means of 

 italics, is the following : — " The anchovy comes in shoals into the 

 Zuyder Zee in order to spawn ; those which are not captured de- 

 part after spawning, except a few which remain behind. The young 

 brood remain during the first months of their life in the Zuyder 

 Zee ; they grow very fast, and at the end of October have already 

 reached a length of 12 cm. ; then, and not till then, the young 

 depart. ^^ 



At the time when Hoffmann formed this conclusion the larval 

 stage of the anchovy was unknown, and the fertilised eggs had not 

 been seen. But Hoffmann had himself observed that the anchovies 

 in the Zuyder Zee were sexually ripe in the latter half of June and 

 in July. In the last week of July all the anchovies he obtained had 

 just shed their spawn. He argues that temperature has a very great 

 influence, not merely on the time of development of the eggs of fishes, 

 but on their rate of growth, and that the anchovy grows very fast 

 on account of the high summer temperature of the water of the 

 Zuyder Zee. He refers to Meyer's result concerning the spring 

 herring in the Baltic, namely, that the young hatched in April and 

 May reach a length of 3*5 to 4*2 cm. in two or three months. 



* Bijdrage tot de kennis der levenswjze en der voortplanting van de ansjovis, Verslag 

 van den Staat der Nedfrlaiulsche Zeevisscherijen over 1885, Bijlage ii. 



