10 Part III. — Twenty-sixth Annual Report 



There has thus been an almost contmuous decline since the year 

 1897, which, however, represented the largest quantity which has 

 been recorded as taken from the loch, and the decrease during the 

 last four years has been very marked, and unfortunately still 

 continues. The object of the enquiry was to ascertain, as far as 

 possible, the nature and extent of the annual fluctuations in the 

 abundance of the herrings, their causes, and the movements of the 

 shoals into and out of Loch Fyne. In last year's Report a paper was 

 published dealing with all the available statistics for the period 

 from 1854 to 1906, and showing the annual fluctuations which had 

 taken place in that period. It was brought out that about thirty- 

 three years ago a very similar time of depression and poor fishing 

 occurred, the yield gradually falhng from 39,795 crans in 1868 to 

 3648 crans in 1873 and 4806 crans in 1874, after which it rose, at 

 first with some irregularity, to 55,754 crans in 1882, the second 

 largest quantity recorded from the loch, and fell again to 1886 and 

 1887, when it was considerably below the average. There is no 

 good reason to suppose that the present poor yield will not be 

 followed by corresponding years of abundance as in the past, or 

 that it is in the main, at all events, anything but the trough of one 

 of the waves of scarcity and plenty which have characterised the 

 fishing during the last half-century. The investigations to which 

 reference has been made comprise the determination of the 

 temperature of the water, the abundance of the planktonic food of 

 the herring, and the examination of samples of fish from various 

 parts of the Clyde in reb.tion especially to the condition of the 

 reproductive organs. Variations in the temperature of the sea and 

 in the quantity of food upon which the herrings live are believed 

 by many to be causes producing fluctuations in the herring fishery, 

 and when observations are completed, that is, when the herrings 

 return in something like their normal numbers, they will probably 

 show to what extent this explanation is correct. In addition to 

 the regular serial observations of the temperatures in Loch Fyne 

 made by means of a small yacht, other observations have been 

 made in the Clyde by the fishery cruiser " Vigilant." 



The Decomposition of Fish. 



In the present Report will be found a paper by Dr. A. G. 

 Anderson giving the results of an investigation undertaken by him 

 on the processes involved in the decomposition of fish, including a 

 bacteriological study of the subject, the observations and experi- 

 ments having been made partly at the Board's Marine Laboratory 

 and partly in the laboratories of Marischal College, Aberdeen. 

 Fresh fish, from its essential nature, readily undergoes decomposi- 

 tion, the process being associated with and chiefly caused by micro- 

 organisms which are universally present, the three cliief factors 

 which facilitate or inhibit their action being the supply of 

 nourishment, the temperature, and the degree of moisture. 

 Compared with the red muscles of mammals the pale muscles, or 

 edible portion, of fishes have usually less fat and much more 

 water, are slightly less vascular and looser in texture, and are thus 

 more susceptible to the attack of putrefactive micro-organisms. 



