652 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



By measuring a large number of herrings caught on the coast of Bohus- 

 lan during the latter part of spring, I have found that the majority of 

 herrings in that region may, according to their size, be divided into three 

 groups, namely, 1, those measuring 100 millimeters (total length 120 milli- 

 meters), which must be considered as one-year-old-fish;^^ 2, those measur- 

 ing 145 to 150 millimeters (total length 170 to 175 millimeters), which 

 must be considered as two-year-old-fish ; and 3, those measuring 175 

 millimeters (total length 200 to 210 millimeters), which are presumably 

 three years old, and have fuUy-developed sexual organs. Occasionally 

 I found a fish measuring only 160 millimeters (total length 185 milli- 

 meters) which had loose roe,^* as well as fish measiu-ing 160 to 170 milli- 

 meters (total length 185 to 200 millimeters), which could not possibly 

 have become ready for spawning that same year. Larger fish , measuring 

 about 200 millimeters (totaj. length 23 J centimeters), are probably four 

 years old.^^ As a considerable portion of the food which the herring 

 eats and assimilates is directly or indirectly used for the formation ot 

 the milt and roe, the growth of the herring in size is, of course, a slow 

 process.*^^ The circumstance that the spawning season of our coast-her- 

 rings extends over a period of at least several months, causing a consid- 

 erable difference of age among the young fish, and a difference in their 

 abiUty to seek and obtain food, with other accidental circumstances, 

 must be considered as the cause why in one and the same net fish of 

 every possible size may be caught.*^'' 



The Bohuslan coast herring seems to spawn for the first time when it 

 is three years old, although this must by no means be understood as if 

 all fish born in one and the same year must spawn at that i^articular 



^ According to the extensive investigations of tlie German Fishery Commission, the 

 growth of the young herrings in the southwestern portion of the Baltic is more rapid 

 during spring than my observations on the coast of Bohuslan have shown it to be. 

 In the above-mentioned j»art of the Baltic the herring are said to reach a total length 

 of 130 to 140 millimeters during the first year, i. e. 10 to 20 milluneters more than my 

 observations showed. {Jalireshericht, IV-VI, p. 246. ) 



^^In reproducing my observations (Preliminar herdttelse, 1873-74, p. 35) in the "Jahr- 

 eshericM der commission zur wissenscha/tUchen Untersuchimg der deutschen Mcere in Kiel" 

 (IV-VI, J). 247), the circumstance seems to have been overlooked that my measure- 

 ments do not include the caudal fin, which of course increases the length considerably. 

 I have in doing so followed the custom of other writers, amongst the rest Axel Boeck, 

 who does not count in the caudal fin. Modern writers, as well as some of the older 

 ones, have followed a different course in this respect. Desii'able as uniformity in this 

 matter would be, the choice must be left to individual opinions ; only for the sake of 

 avoiding mistakes it should always be mentioned what length is meant, and this has, 

 unfortunately, not always been done. 



65 j^_ \y ^ Malm's observations agree with this, as he says that fish having a total 

 length of 190 to 220 millimeters *'are presumably in their fourth year," and that fish 

 measuring 300 millimeters (total length) ''are probably upwards of 6 years old" (Fauna, 

 pp. 573, 577). 



^ Judging from the observations of the German Fishery Commission, the later growth 

 of the herring is not quite so slow as I have mentioned above. 



''^See "Preliminar herdttelse," p. 156. 



