of the Fishery Board for Scotland. 



103 



It is possible that for a short time (a month perhaps) after spawning 

 the herring does not take food. 



There are without doubt similar periods during the reproductive life 

 of herrings from all districts. Heincke's statements with regard to the 

 storage and using up of the muscle fat were based on no analytical 

 evidence. 



There are still many points in connection with variations in the 

 metabolism in herrings during spawning which require to be worked out, 

 especially the cycle of phosphorus between muscles and ovaries. 



Before concluding, I should like to refer to a subject which is at 

 present attracting a good deal of attention, namely, the nutritive value 

 of spent herrings. 



Statements are made vaguely as to the unwholesome character of the 

 spent fish. Now, upon what foundation does this rest? Usually upon no 

 further evidence than the general appearance of the flesh of the fish, 

 which is undoubtedly poorer in fat than in the maturing herring. But 

 the nutritive value of the fish does not depend solely upon the fat which 

 it contains ; the percentage of proteid must also be considered, and if the 

 tables of analyses be consulted, it will be seen that in this respect the 

 spent fish compare by no. means unfavourably with the maturing or 

 mature fish. 



But there is one other point which one must bear in mind, namely, 

 that in many cases spent fish contain a large percentage of fat in their 

 muscles, and to illustrate this I include some tables of analyses of fish 

 caught in Loch Fyne in May and June of this year. In many cases 

 these were fish which were undoubtedly storing fat after the discharge of 

 ova had taken place. It is true that this storage of fat does not take 

 place to any marked extent until three or four months have elapsed since 

 the last spawning took place, but still the herrings present the appearance, 

 so far as the genitals are concerned, of spent fish. 



Again, the poverty of fat in the muscles of freshly spent herring may 

 render them more digestible in the case of some individuals at least. 



One must also remember that fully mature fish about to spawn are in 

 much the same condition as freshly spent fish (vide Helmsdale herrings, 

 December 6), and yet these fish would scarcely be termed unwholesome. 



It would have been of extreme value to have had analyses made of 

 herrings which had left Loch Fyne in January and gone to Kilbrannan 

 Sound and Campbeltown district • but unfortunately I was unable to 

 obtain specimens. 



I subjoin the analyses to which I have just referred. 



Attention may be specially directed to the analyses of the flesh of the 

 large spent fish of June 2, as these show a comparatively high fat 

 percentage. 



May 16, 1906. 



The herrings sent on this date from Ardrishaig were young immature 

 fish. The genitals of 16 of these herrings weighed only 2 f 15 grammes, 

 and the ova were exceedingly small, "OS-'OSmm. 



[Table. 



