4d 



This list shows clearly tliat little sinelts of t'roni 50 — 70 niillim. 

 are to be fouud tliroughout the whole year. Only betweea the 

 second half of April and the first half of July these very small 

 ones have disappeared , at least have growu very seldora in the 

 kuilnets: the size of the smallest fishes in that time is 75 — 90 m.ra. 

 In the beginning of July it is again the turn of the smallest 

 ones to show themselves. Hitherto almost nothing was known with 

 regard to the reproduction of the smelt in the Zuiderzee. About 

 one point iuformation was quite wanting: the spawning-places 

 of the smelt were unknown. There was reason to believe that 

 the spawning of this fish did not happen in the Zuiderzee itself 

 but was to be looked after in the river IJsel and perhaps in 

 other rivers also. I paid special attention to the subject and the 

 results of my investigations are as foUows. 



It is true that tbe smelt ascends the river IJsel in spring 



— it is also undoubted that these fishes do so to spawn in the 

 fresh water of this river. However it is not true that this is 

 done by all the smelts : there are also some (and probably they 

 are very numerous) which stay in the Zuiderzee and produce their 

 offspring there. T did not study the spawning places of the smelt 

 high up on the river IJsel , but I met with the smallest larvae 

 of this fish in the Zuiderzee. One could think , though it would 

 have been rather improbable, that these little larvae had descended 

 already from the IJsel or were carried down by the current of 

 that river: in that case one would find these larvae also in the 

 mouth of the river or in that river itself below Kampen, about the 

 time that the most numerous and the smallest larvae were observed 

 in the S. E. part of the Zuiderzee. On the same day (12 July '88) 

 on which I collected with a single sweep of the surface-net 



— at a distance of one quarter of an hour outside the Ketel — 

 a whole bottle of younger and older smelt-larvae, I did not 

 succeed, either in the IJsel below Kampen, or in the Ketel, in 

 catching a single larva , though I fished six times at dift'erent 

 places always with two surface-nets at the same time. 



The spawning places of the smelt in the Zuiderzee are in the 



