71 



These lierrings so distinctly corres[)Ond witli one another that 

 Olie feels inclined — eveu tliough their number is so very 

 small — to poiut tbeni out as represeutatives of a true herrin<^- 

 race, even more so tban is the case witb tbe Zuiderzee-berring. 

 However, tbe latter in tbis respect excel again tbe berrings of 

 tbe Hollaudscb Diep and tbose of tbe Haringvliet; tbe not 

 very numerous specimens caugbt in tbese estuaries do not sbow 

 a distinct type: wbereas some of tbem migbt be considered as 

 Nortbsea-berriugs, otbers mueb more resemble tbose of tbe Zui- 

 derzee-race. 



A very interesting point in tbe study of tbe Zuiderzee-berring 

 treats of the questiou, wbetber tbere differeuces between autumu- 

 and spriug-berrings exist or not. Some years a bit earlier, otber 

 years later a herring enters tbe Zuiderzee during tbe last montbs 

 of tbe year. In tbe autumn of '88 wben I was engaged in the in- 

 vestigation of tbe Zuiderzee-fisbery only very few berrings were 

 caugbt. In October and November '89 tbe catches of berrings 

 were ratber important ; I availed myself of tbis opportunity to 

 settle tbe question wbat kind of herring was tbis Zuiderzee- 

 autumn-berring. To understand tbe importance of tbis question the 

 following much be borne in mind. In early spring, as soon as the 

 water of tbe Zuiderzee gets free again from tbe drift-ice whicb 

 (mainly frora tbe IJsel-river) enters it, berrings begin to show 

 tbemselves, and a very active fisbing sets in. In some years tbis 

 happens towards tbe end of January or tbe beginning of February, 

 in otbers not before the beginning or middle of March, and from that 

 time tbe herring fisbing is continued until tbe middle or end of April. 

 As we have seen above (p. 57), about that period tbe spawning 

 of the berrings takes place, and, as soon as it is finisbed, a 

 period begins during whicb no berrings enter the Zuiderzee. Tbis 

 lasts till autumn, wben, about tbe end of September, new sboals 

 make their appearance. In October and November herring- 

 fishing takes place in the Zuiderzee and in some years is even 

 revvarded witb abundant catches. As a rule it draws to a close 

 towards tbe begiuniug of December, and it is a very popularo})!- 



