REPORT OF THE COMMISSIONER OF FISHERIES. 71 



PROPAGATION OF MARINE SPECIES. 



Taken as a whole, the output of the marine stations exceeded that 

 of 1916 by more than half a billion fish and eggs. Owing to conditions 

 over which the Bureau had no control, the volume of the lobster and 

 cod operations was somewhat lessened in comparison with the previous 

 year, but the shortage in that direction was compensated for by the 

 largely increased production of pollock and flatfish. 



On account of the limited funds available and the excessively high 

 cost of lobstei-s, only 14,660 adults were purchased as a source of egg 

 supply for the Boothbay Harbor station, this being a smaller stock by 

 several thousand than had usually been secured for that purpose. 

 The lobsters were acquired and installed in the pound between July 1 

 and September 30, and during succeeding months the}^ received 

 the close attention of a caretaker who fed them regularly, maintained 

 a uniform water temperature in warm weather by opening and closing 

 the gate valves of the pound at a specified time each d^j, and guarded 

 against pollution by the removal of all debris from the inclosure at 

 frequent intervals. In April the stock which was in the pound was 

 transferred to live cars at the hatchery until the lobsters could be 

 relieved of their eggs, after which they were turned over to the Maine 

 Department of Fisheries. 



Those surviving confinement amounted to 10,976, or nearly 75 

 per cent of the original number, which shows merely an average loss, 

 considering the long term of confinement to which they were sub- 

 jected. It was found there had been an appreciable loss of eggs 

 through premature hatching in the pound, and there were indications 

 that some of the barren lobsters had been stripped by eels, notwith- 

 standing the vigilant efforts made to prevent this by the regular 

 setting and tending of baited eel traps. In the course of the year 

 many large eels were caught in this. way, but it was impossible to 

 capture the small ones. On accoimt of the losses mentioned, only 

 104,445,000 eggs were realized, the average per lobster being 9,516, 

 or slightly less than that of last year. The percentage of eggs 

 hatched was 98. The fine quality of the fry is justly attributable, 

 in part, to the adoption of large, flat, wooden baskets for removing 

 them from the pound, thus reducing the amount of handhng that has 

 heretofore been required. In the future it is intended to use these 

 baskets exclusively, not only when unloading the pound but when 

 making transfei-s thereto. During the spring months all available 

 ''seeders", amounting to 237, were purchased and from this source 

 5,615,000 adcUtional eggs were obtained. 



On March 1 fyke nets were set in waters adjacent to the Boothbay 

 Harbor hatchery, and from that time to the close of April the force 

 was busily engaged in acquiring a brood stock of flatfish. To this end 

 new fislung grounds were resorted to, and extended collections were 

 made in Casco Bay and farther westward by means of the station 

 steamer. The total number of brood fish obtained from all sources 

 amomited to 7,775; these yielded 1,085,32^,000 eggs from which 

 966,266,000 fry were hatched, a percentage of 89, The fry were 

 liberated in the usual manner, and in waters near where the fish had 

 been caught. 



As in past years an experimental shipment of pollock eggs was 

 made from the Gloucester station by means of the steamer Gannet, 



