of the Fishery Board for Scotland. 



Ixi 



Ypar- Herrings y Herrings 



Caught. Caught. 



1901, - - 29,117 cran.s. 1906, - - 5,258 crans. 



1902, - - 26,389 „ 1907, - - 3,914 „ 

 1908, ■ 21,198 „ 1908, - - 4,070 „ 



1904, - - 7,827 „ 1909, - - 3,684 „ 



1905, - - 4,672 „ 1910, - - 2,665 „ 



A study of the statistics shows that in the years 1871 to 1880, 

 incUisive, the catch of herrings in Lochfyne remained under the 

 average annual catch of 25,180 crans above referred to, the quantity 

 gradually sinking from a high point in 1868 to the low level of 1873 

 and 1874, after which it gradually rose again, with an exceptional fall 

 in the year 1878, to the second highest point reached in the records, 

 namely, 55,754 crans in 1882. Thus fourteen years separated the 

 great fishcjry of 1868 from that of 1882, and fifteen years separated 

 the latter from the still greater fishery in 1897. There was, however, 

 this difference, that in the first period of low returns there was a brief 

 rise to nearly the average, and in the second period a considerable rise 

 above the average, lasting for some years, while no upward change of 

 the kind has occurred in the depression at present existing. 



Lochfyne is not peculiar in exhibiting such variations in the abun- 

 dance of the herring frequenting its waters. Similar fluctuations, 

 particularly in fjords or arms of the sea, are of not infrequent occur- 

 rence on other coasts and in other countries, and have been attributed 

 to various causes, sometimes natural and sometimes arising from the 

 actions of man, but no satisfactory explanation has as yet been 

 advanced. Variations in the temperature or salinity of the water, or 

 in the quantity or kind of the floating food upon which the herring 

 chiefly subsists, are believed by many to be the principal causes of the 

 fluctuations, and since 1904 observations have been carried on in 

 Lochfyne, and were continued last year, with the object of ascertain- 

 ing if this is the case. At a number of places in the loch a series of 

 temperature observations are made at different levels and collections 

 of the floating herring food secured, and it is proposed to continue 

 these until the herrings return to Lochfyne in something like their 

 former abundance, and afterwards, so that comparison may be made 

 between the two periods. It is not improbable that the vagaries of 

 the herring in this and similar cases may be due to what may be 

 termed accident. Reasons have been given in former reports to show 

 that the herring in the Clyde tend to visit a locality in increasing 

 numbers, or to withdraw gradually from it, for a number of years in 

 succession, and this may occur in a very limited part or in a large 

 area. Thus in Lochfyne the fluctuations are not such that a good 

 year and a bad year come in succession. There is a series of good 

 years, getting better and better, and then a gradual decline, the fish 

 becoming scarcer and scarcer. It is probable that if a shoal should 

 enter the loch, and be not too much disturbed, they would tend, in 

 accordance with the habit referred to, to return in greater and greater 

 numbers in the following years. In addition to the observations on 

 the temperature of the water and the abundance of the plankton, 

 samples of the herrings are periodically examined, with reference 

 more particularly to their condition and reproduction. 



