52 U. S. BUREAU OF FISHERIES. 



diatoms were found throughout this region, Buzzards Bay, and 

 Vineyard Sound, and great numbers were carried into Great Harbor 

 (Woods Hole) by the strong currents and winds. It was noticed 

 that after a thaw or heavy rain a considerable increase in the number 

 of diatoms occurred, while repeated observations indicated that this 

 was not a mere coincidence. A possible explanation may be that 

 the drainage from the land increases the necessary food products 

 of the diatom in these local waters. The particular diatom 

 {Rhi2osole7iia alata) that usually interferes with propagation of cod 

 at Woods Hole does not ordinarily occur until the temperature of 

 the harbor water drops to about 35° F. It is not possible to relieve 

 the situation by changing the source of water supply. 



The best results are obtained in cod propagation when the water 

 temperature is from 42° to 47° F. Therefore it is proposed here- 

 after to heat the water used in cod propagation at times when the 

 temperature falls below 47°, and to maintain the supply at a point 

 5° above the temperature of the harbor water until the cod work is 

 completed. Owing to the arrangement of the heating pipes in the 

 hatcher}', this undertaking will entail no additional expense. 



As in past years, operations were conducted in Waquoit Bay for 

 the purpose of obtaining a brood stock of winter flounder, this work 

 extending from January 16 to March 20, Though prosecuted with 

 the utmost vigor, the efforts to this end were rendered almost neg- 

 ligible by the difficulties met with. Not only were weather and road 

 conditions such that it was often impossible to attend the nets for 

 several days at a time, but there were very few fish on the spawning 

 grounds. It was ascertained that one 42-foot fishing boat operating 

 just outside the entrance of the bay early in November, just at the 

 time the fish were beginning to enter it. had cleared a profit of 

 $1,400 as a result of 10 days' fishing. This boat must have taken 

 approximately 7 tons of winter flounder, representing about 9,000 

 fish, and it is possible that to the operations of this and other ves- 

 sels may be attributed the unwonted scarcity of fish in this field. 

 The efforts to obtain a brood stock of this species were also extended 

 to the Wickford (R. I.) field. Work there was undertaken on 

 March 16, but the returns up to April 4 were so poor that the at- 

 tempt was abandoned. The total collection of eggs from fish taken 

 in these two fields amounted to only 369,865.000, less than one-third 

 the number secured in 1922. 



On February 17, when hatching operations were in full swing, 

 the water supply was shut off by the freezing of the suction pipe. 

 To meet the emergency thus created the Coast Guard steamer 

 Acushiiet agreed to furnish the water required to keep the hatchery 

 in operation, but at the expiration of 24 hours' service the steamer 

 was obliged to take up other duty and nothing remained to be done 

 but liberate all stock on hand. The plants made at this time con- 

 sisted of 115,897,000 green eggs, 102,354,000 eyed eggs, 10,000,000 fry, 

 and 400 brood fish, all winter flounder. 



The usual efforts were made during the spring to obtain eggs of 

 the mackerel, scup. and sea bass. On several occasions a few eggs 

 of the two first-named species were secured, but in the absence of 

 a fertilizing medium tliev were of no value. 



