THE SEA-FISHERIES 301 



in 1915, the latest year for which statistics are completed, 

 the Pacific shad-fishery yielded over 7^ miUions of pounds, 

 valued at over 75,000 dollars. 



In addition, extensive operations in the hatching and 

 setting free of fry are conducted on the Atlantic coast. 

 Over 52| miUions of shad-fry from the hatcheries were 

 distributed in 1918 in the Eastern States. In the Commis- 

 sioner's report for 1921 (pubHshed in 1922) it is stated that 

 the two hatcheries then working were distributing aU their 

 fry locally in Maryland and North Carolina, and the report 

 adds : " In view of the conditions that exist in other shad- 

 streams where artificial propagation is not conducted, it 

 seems but just to assume that the hatcheries have been a 

 factor in maintaining the shad-fisheries in their vicinity." 



The Fishery Board for Scotland carried on for some years 

 an interesting experiment in adding artificially hatched 

 plaice larvae to a circumscribed sea-area (Upper Loch Fyne) 

 with the view of determining whether an increase was 

 noticeable in the number of young fish present. Positive 

 results seem to have been obtained. During a period of 

 six years, millions of larvae were hatched at Aberdeen and 

 deposited in Loch Fyne, and during the next six years none 

 were added ; while during the whole period of twelve 

 years experimental hauls of the net were made on certain 

 selected beaches where the young metamorphosed plaice 

 congregate. The statistical results apparently indicate that 

 during the years when larvae were added the number of 

 young fish caught, per hour of fishing, was more than 

 double the number caught in the succeeding period of six 

 years. Or, to put it another way, the figures given in the 

 report show that the addition of about 20 miUions of plaice 

 larvae a year doubled the number of young metamorphosed 

 fish on the shallow beaches of Loch Fyne. 



It has sometimes been said that the young fish turned out 

 from hatcheries may possibly be weaklings, which, on account 

 of having been reared under artificial conditions, may die 



