39 



present the total number of fishes occurring iu the Zuiderzee 

 ordinarily or only temporarily. A few of them are true fresh- 

 water fisbes, aud of these some (perch , ruö', pike, gudgeou and 

 bleak) were observed only once , or twice as was the case with the 

 roach: there is no reason for entering into details as to these fishes. 

 I only wish to state that the perch and the gudgeon were caught 

 in very uearly fresh water near Schokland; that the pike and 

 a couple of roaches were taken in a »kwakkuil" near the south- 

 coast — not far from the Muiderzand — , whereas the rufi's, the 

 bleak and the other roaches were caught to the south of the 

 en trance of the „Kamper Ketel" (mouth of the river IJsel). 



Of the 18 remaining fishes the sea-stickleback , the lesser- 

 launce, the garfish and the sea-snail have only been observed 

 once : the sea-stickleback between Volendam and the Nek , the 

 lesser-launce not far from the Knar , and the garfish between Urk 

 and the Enkhuizer Zand ; the sea-snail was fouud in the con- 

 tents of a „kwakkuil" which had been fishing in the Hop. An- 

 other and very sniall specimen of the garfish was taken when 

 a pelagic net was used ofl Blokzijl at a distance from the coast of 

 about 4000 Meters. None of these four fishes can be considered 

 to belong to the fauna of the Zuiderzee proper. 



Neither is this the case with the sole ; only small specimens, 

 and those moreover exceptionally, were observed in the contents 

 of the „kuil" nets. The sole spawns in the Northsea near the 

 coast; the newly born soles probably disperse in different direc- 

 tious and some of them enter the Zuiderzee. When winter ap- 

 proaches the sole removes to the deeper parts of the Northsea 

 and most probably those few specimens which entered the Zuiderzee 

 will also try to reach the open sea again. (In the Vuilegat, between 

 Hollandsch Diep and Haringvliet , a couple of small soles were 

 also taken in a so-called »Ankerkuil", which was fishing there). 



Thirteen species of fishes are left. They can conveniently 

 be divided in such as are important for the fishery (plaice, 

 Sounder, smelt, herring, sprat, anchovy and eel) and such 

 which from an ecouomical point of view are of a very proble- 



