16 REPORT OF THE COMMISSIONER OF FISHERIES. 
fish at the time of delivery, and to avoid constant weighing an aver- 
age weight of 114 pounds per fish has been established as a basis for 
computing the cost, this being conceded by the fishermen as a very 
fair average. The fish thus purchased are released immediately after 
their eggs are secured, and they undoubtedly return to the river in 
appreciable numbers in subsequent years. The point of greatest 1m- 
portance, however, is the salvage of a very large percentage of the 
immature spawn contained in the fish at the time of capture for 
market. 
The shad hatcheries on both the Potomac River and Albemarle 
Sound were adversely affected by peculiar climatic conditions that 
prevailed during the spring of 1921. In the former field the first 
eggs were taken on March 22, the earliest recorded date for spawn- 
ing shad on the river. This premature spawning was undoubtedly 
brought about by the warm weather and consequent high water-tem- 
peratures prevailing in the latter part of February and in March, 
the minimum water temperature recorded at the Potomac River sta- 
tion during March being 40° F. An unfavorable reaction was occa- 
sioned by the abnormally cold weather in April and early May, when 
the season was brought to a close. Equally unsettled weather pre- 
vailed in the Albemarle Sound region, and to this fact, together with 
the very extensive fishing operations permitted in the sound, the re- 
duced output of the station is due. 
Tt should not be necessary to emphasize the great need for imme- 
diate restrictive measures if the shad is to be saved in the few remain- 
ing rivers where the run still persists in sufficient volume to be com- 
mercially attractive. The subject has been a prolific source of dis- 
cussion, but the various States most intimately concerned and re- 
sponsible for the conditions have apparently made no progress toward 
ameliorating the situation. It is pertinent to note that the weather 
which was so unpropitious for the hatcheries actually favored a large 
catch of fish in the pound nets in the lower reaches of Chesapeake 
Bay and Albemarle Sound. 
Very good results attended the initial attempt to propagate the glut 
herring or alewife on Albemarle Sound, and over 55,000,000 eggs 
were collected for the Edenton hatchery and nearly 44,000,000 fry 
were produced. The hatching of striped bass on the Roanoke River 
was conducted as usual in the spring of 1921, and, notwithstanding 
unfavorable weather, the collection of eggs, amounting to 24,620,000, 
was larger than in any previous season. 
PROPAGATION OF COMMERCIAL FISHES OF THE GREAT LAKES. 
The most important commercial species of the Great Lakes—white- 
fish, cisco, lake trout, and pike perch—were handled along the custom- 
ary lines, and, with the exception of the lake trout, all showed a 
satisfactory increase in output as compared with the previous year. 
This increase was made possible largely by favorable weather con- 
ditions, although in the case of the cisco the egg collections were 
greatly augmented by the receipts from new fields in the Canadian 
waters of Lake Ontario. 
The need of a hatchery at some point on Saginaw Bay to take care 
of the immense numbers of pike perch and yellow perch eggs avail- 
