THE SALT-WATER FISHERIES OF BOHUSLAN. 207 



8. The capriciousness of the herring or its innate instinct independ- 

 ent of outward circumstances. ^ 

 B.~Causes produced hy human agencies : 

 1. The gradual destruction of the herrings by : 

 a. too much fishing, and more especiall/b*y catching vouns her- 

 rings in close nets, ^ 



I. preventing the herrings from reaching suitable spawning-places 

 c. destroying the spawn, or * r^^-ces, 



.Z destroying the places where the young fish are accustomed to 

 seek food and shelter ; 



2. The gradual expulsion of the herrings from the coast-waters by 

 a. noise, -^ • 



1). too many fishermen, 



.disturbing methods of fishing, especially fishing with floating 

 nets too early m the season, *= 



d. disturbing the spawning-process, 



'■ tkf ™terf """ '""""'"S-Pl^««« "y fl'-W"? «■ aiwiDg refuse into 



'■ oftfif t,e re^^ "" '"^ ^'»"''"' - t-^'-'-B- ^te and ,m 

 g. making the water impure by refuse from oil-reflneries, &c 

 ing"placef; *"' ^'""°' "'""" ^"'"^ ""O'^turbecUy to their- spawn- 



'■■ itrt rerrin^r' '^''"'»" ""'^ ^"^ -'-^»-* --''^ "^ 

 C — Biological and physical causes: 



1. Gradual destraction of the herrings by unfavorable weather an 



IXffooTrr '"' "™''" "''-''■'''-'''' ""^ -^"^^■o^^-™ 



2. The forced exp.dsion of the hen-iugs from the eoast-waters by ■ 

 «. the mcreasmg number of flsh-of-prey and birds-of-prey, 



h. the lack of food, ^ ^' 



c. a change in the nature of the coast-bottoms, making them unfit 



'•tfei"f>:rii";i:Styr'^'*"'''"^*'" ^"" '""'*'"'^"" --<•'«»--- 



SS^'lf win'^""^',"",""*' '" ^° *"'' ^'"' f™-" '^"^ «"''«* i" search of food, 

 less nulbe nfT f * "''"'''''y '" '"^ '^»' fr«1"ently a greater or 

 to ,r,r ' above-mentioned causes have been combined in order 



I tSnto?hfr'" '*"'•■ ^"^ ""' " "^^ — -y to gfv mat 

 thev have ?o „ 1 f "™'»>ied under the first headiug (A), although 



hey,^li^™tH.',,T v""?*'"""'' ™'^'''' *''« ^^e""" Heading (B), 

 tuey m,,ht practically be dmded into two subdivisions different from 



