472 



U. S. BUREAU OF FISHERIES 



were planted on the spawning grounds immediately after fertilization had been 

 accomplished. A few millions, reserved with the" object of testing the water 

 supply at a new site on the Bayou Plaquemine, were successfully incubated at 

 that point with only a 2 per cent loss, and the resulting fry were vigorous and 

 healthy. On account of the higher water temperature at the new site, the in- 

 cubation period is materially shorter than at Atchafalaya. 



Mussel Infection in Conjunction with the Rescue of Landlocked Fishes 



[H. L. Canfield, in charge] 



As in past years, mussel-infection operations were conducted in connection 

 with the salvage of food fishes from overflowed lands along the Mississippi 

 River. This work is receiving the hearty commendation of practically all who 

 are engaged in the various branches of the mussel industry, including clammers, 

 buyers, and pearl-button manufacturers, and many of them have expressed their 

 approval in writing. 



While weather conditions during the summer and fall of 1924 were unfavorable 

 for the prosecution of the rescue work, they were in the main favorable to infection 

 operations. This is explained by the fact that only strong, vigorous fish can be 

 used to advantage in the infections, and during protracted warm periods most of 

 the fish handled are so soft that they will not successfully endure the treatment. 



The first five-year term of the mussel closure law in force along the Mississippi 

 River and its tributaries in Wisconsin, Minnesota, Iowa, and Illinois having 

 expired, the areas in which it was applicable are now open, while other areas will 

 be closed for a second period of five years. No definite data as to the effects of 

 this law will be available until the close of the second period, but judging from 

 current reports it is believed it has proved beneficial. 



The fields in which mussel-infection operations were conducted during the 

 year and the numbers and species of mussels handled in each are shown in the 

 following table: 



Summary of infection of fishes, fiscal year 1925 



' This mussel is not of best quality and fishes are infected with it only when first-class mussels are not 

 available. 



MARINE FISHES 



A very successful season was experienced in the propagation of 

 the marine fishes of the New Enghind coast. The eggs collected at 

 the three stations comprising this group aggregated 4,886,182,000, as 

 compared with 4,049,135,000 in the preceding year, while the output 

 of eggs and fry amounted to 4,092,807,000, a gain of about 13 per 

 cent compared with corresponding figures for 1924. The heavy 

 increase shown is accounted for by the phenomenal abundance of 

 cod in fields around Gloucester, Mass., and by an unusually heavy 

 run of winter flounder along the Maine coast. 



