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Appendices to FovHli Annual Report 



the subject from another point of view. More particularly it is necessary 

 to know not only what forms are found in a fish's stomach, but also the 

 relative abundance of these forms in the sea itself, and also what choice 

 of food material was at the time available. Our attention must ultimately 

 be directed to the conditions under which the ' food material ' itself exists. 

 For the present, only one part of this subject has been studied. During 

 the time that the Fishery Board's Laboratory was open in Loch Fyne, 

 Mr Calderwood made frequent collections of the Copepods found in the 

 district. It has thus been possible to compare in this case the number 

 and frequency of the forms ascertained by surface dredging with those 

 actually found in the stomach of the herring. 



I. 



REPORT ON THE FOOD OF THE HERRHSTG. By G. Beook, 

 F.L.S., and W. L. Caldehwood. 



The food of the herring has frequently formed the subject for inquiry 

 during the past few years, both in this and other countries, and we are 

 already in possession of much valuable information on the subject. So 

 long ago as 1843 Goodsir pointed out that the herring on the East Coast 

 followed the large shoals of Entomostraca from place to place, and that 

 the presence of herring near our shores was largely dependent on the 

 abundance of free swimming Crustacea in the inshore waters. Sars has 

 shown that off the Loff'oden Islands the Calanidse, supply the most 

 abundant forms of herring food, Calanus finmarcliicus and Temora longi- 

 cornis being particularly abundant. 



Mr Sim has also devoted considerable attention to the study of herring 

 food, and has described a large number of forms occurring on the East 

 Coast of Scotland. More recently the question has been studied by Mr 

 Piercy and others, while Dr Mobius has given a list of the chief food 

 forms of the Baltic herring. 



The material on which the present report is based has been supplied 

 during the past two years by the officers of the Board at the chief fishing 

 centres. Altogether, many thousand stomachs have been examined, and 

 over two thousand which contained food have been transmitted to the 

 central laboratory preserved in spirit. We have received considerable 

 assistance in the identification of specimens from Mr Scott, Mr Jamieson, 

 and others employed by the Scientific Committee of the Board. From 

 April to November last a large amount of material was examined in a 

 fresh condition at Tarbert, and compared with the living forms obtained 

 by the tow-net. The importance of such a comparison can scarcely be 

 over-estimated, and in the future we may expect to obtain the most 

 instructive results from a study of the food forms themselves, and of the 

 physical conditions affecting their distribution. This is more particularly 

 the case with the herring, mackerel, and other fishes whose migrations 

 are, to a great extent, dependent on the distribution of the immense 

 shoals of pelagic Crustacea on which they feed. Widegren has already 

 called attention to this point. Speaking of the Copepods as forming a 

 large part of the food of the herring, he says : — ' Their quantity varies in 

 ' different seasons, during a change of temperature, and at different depths, 

 ' and this probably is the reason why these fishes are taken at different 

 ' depths, in accordance with temperature and currents.' 



The food of the herring being chiefly pelagic, the shoais of fish are 



