8 



Fart III. — Twenty-eighth Annual Repor 



The statistics of the Loch Fyne herring fishery extend back to the 

 year 1854, and only in one year in that period was the quantity of 

 herrings caught less than in 1909, and then only by a few crans — 

 namely, in 1873, when 3,648 crans were landed. The poor results 

 of the fishing in recent years is not equalled in the history of the 

 fishery, so far as known, for in the last great depression there were 

 only three years — 1872-1874 — when the quantity was less than 

 10,000 crans. Towards the end of June last year there were 

 indications that a considerable shoal of herrings had entered Lower 

 Loch Fyne, and in the month of July a fair fishing was carried on — 

 the aggregate catch for that month being 2,966 crans, as compared 

 with 3,684 crans for the whole year. The herrings, however, did not 

 penetrate far up the loch, and they very soon left it altogether. 



Similar and apparently unaccountable fluctuations in the herring 

 fishery, more especially in lochs or arms of the sea, are of not infre- 

 quent occurrence, and have been attributed to various causes ; but no 

 explanation that has yet been given can be regarded as altogether 

 satisfactory. Variations in the temperature of the sea and in the 

 quantity of floating food upon which the herring subsists are 

 believed by many to be the principal factors in producing fluctuations 

 in the fishery. The investigations now being made are designed to 

 show whether or not this explanation is the right one. Periodic 

 observations are taken of the temperature of the water and of the 

 abundance of the floating herring-food, and these will be continued 

 until the herrings have returned to Loch Fyne in something like 

 their former abundance. There is no good reason to suppose that the 

 present scarcity will not be followed by years of good fishing, such as 

 have succeeded to the periods of depression in the past. 



The Influence of Temperature on the Development of 

 the Eggs of the Herring. 



At the request of the Government of New Zealand, a series of 

 experiments on the retardation of the development of the eggs of 

 the herring has been carried on at the Marine Laboratory during the 

 last two seasons. The object of the New Zealand Government is to 

 ascertain whether it is possible to delay the development, and thus 

 the hatching, of the ova of the herring for a period sufficiently 

 prolonged to enable them to be carried to New Zealand and dealt 

 with there — a period which is estimated at about 50 days. In last 

 year's Report an account of the first series of experiments was given 

 by Dr. H. C. Williamson, the general result being that it was shown 

 to be possible to delay the development of the eggs for the period 

 required, though the great proportion of them died at an earlier date. 

 The main cause of the mortality was deficient aeration of the water, 

 as it was difficult to secure a sufficient flow cooled to the necessary 

 temperature. The further experiments which were made by Dr. 

 Williamson are described in the present Report, other forms of 

 apparatus having been made use of. The cooling of the water was 

 successfully attained and a much more even temperature secured, but 

 the difficulties of the aeration of the water were not overcome, and 

 although a few of the eggs survived for a period of fifty days, none of 

 them hatched. Check experiments with uncooled water showed that 



