of the, Fishery Board for Scotland. 



95 



little else but immatures were being caught then, and these latter are not 

 included in the percentages. 



It is difficult to decide from the condition of the captured fish whether 

 the spawning process in the herring is very short — a matter of hours, or a 

 day or two at most — or whether it is prolonged over several days, or even 

 passes into weeks. The presence of partially-spent fish would seem to 

 show that it is not a short and single performance. But the fish in this 

 condition are not so numerous as the spent fish which probably become 

 more active, perhaps in the search for food, after the spawning process is 

 entirely finished.* If spawning was a prolonged process, it is likely we 

 would get many more in the partially-spent condition. If it were a matter 

 of only a few hours, it is unlikely that we would get any except by the 

 seine-trawl ; yet the majority of my specimens came from off'shore fishings 

 during the summer months. Expressing the ova and milt by hand is but 

 a rougli test of what is likely to occur under natural conditions. I have 

 found that with fully-ripe herrings about three-fourths of the ova or milt 

 can be expressed ; yet microscopic examination in these cases shows all the 

 ova apparently equally ripe, not only towards the distal portion of the 

 ovary, but also in its deeper chambers. It seems almost certain that the 

 deposition of the roe is not a very prolonged process, and it probably only 

 occupies a few days, during which most of the spawning fish are moderately 

 quiescent. So far as concerns the spawning processes, the appearance of 

 the reproductive organs, &c. suggests no difference between the winter 

 and summer herring, except that the number of spent fish got in the 

 summer fishing is rather greater relatively to the whole catch than is 

 the case in winter, perhaps to be explained by nearly all my winter 

 specimens being got in inshore waters, from which they may retreat more 

 readily and quickly after spawning than they do from the more distant, 

 deeper summer fishing-grounds. 



A condition to be found in the spent fish raises the question of whether 

 the herring spawns once or twice a year. If our winter and summer her- 

 ring turn out to be distinct races, the question of double spawning 

 scarcely needs to be considered, and our knowledge of the spawning habits 

 of other fish would lead to the supposition that they only spawn once in 

 the year. I reserve some observations on this matter for fuller investiga- 

 tion, but the condition referred to above may be mentioned, being one 

 which may indicate a double spawning, or, as I think more probable, 

 shows that the development of the ova within the ovary is very much 

 slower in its earlier stages than in its later. In newly spent — even in not 

 wholly spent — fish there is often to be seen a large number of small ova. 

 It is not an uncommon occurrence to find in what may fairly be called a fully 

 spent fish a few full-sized and fully-ripe ova still unshed. I have found 

 as few as twelve, as many as eighty, scattered through the ovary, t mostly 



* The general opinion about the feeding of the herring supports this statement, 

 but I have considerable doubt as to the correctness of the belief that the spawning 

 iish do not feed, or feed little, and that the spent do so to a much larger extent. The 

 observation casually made when examining the reproductive organs of a large number 

 of fish leads to the conclusion that the prevalence of this habit, judging by the con- 

 dition presented by the stomach alone, is somewhat underestimated, for an 

 examination of the lower part of the intestine, in six or seven cases out of ten, gives 

 evidence that food, generally recognisable as different species of Crustacea, must very 

 lately have been consumed, and there do not appear to be more spent fish with food 

 in their stomachs than of ripe fish. 



t Considering the number of eggs ordinarily present in the herring this number is 

 insignificant. Day gives 10,000 to 30,000 as the number of eggs in the herring. This 

 is a fair statement, but I think slightly below the average, for of a number of fish 

 whose roe I have examined I find the highest reaches 48,000 ova. About one-third 

 had between 30,000 and 40,000, and there were far fewer with 10,000 to 20,000 ; the 



