REPORT OF COMMISSIONER OF FISH AND FISHERIES. XLI 



Several times during the season the capacity of tlie vessel was taxed 

 to its utmost, and on two occasions it was found necessary to transfer 

 eggs to other stations. In addition to the jar, various forms of appa- 

 ratus, such as the Seth Green boxes, tidal boxes, and aquaria, were 

 employed temporarily in hatcbing. 



The shad work was discontinued on June 14 and the vessel pro- 

 ceeded to Woods Hole, arriving there June 10. It was the intention to 

 remain here for a time, to cooperate in the collection of mackerel eggs 

 near Edgartown, but after waiting for several days and failing to secure 

 any eggs she proceeded on June 24 to Oasco Bay and ancliored in Orr 

 Island Harbor. This location was selected as the base of operations 

 on account of its being the headquarters of the mackerel fishermen ; it 

 was also in easy communication with Portland, where large numbers of 

 lobsters are collected. Arrangements were at once made for the spawn- 

 takers to attend the pound nets in the vicinity and to accompany the 

 drag-net fishermen regularly on their trips. The weather at this time 

 was so bad that the drag-netters Avere often prevented from going out, 

 and on July 13 a southwesterly gale completely wrecked the pounds at 

 two of the fisheries. As a result the total number of mackerel eggs 

 secured amounted to only 990,880, most of which were taken from the 

 l)ounds on Jaquish Island. The period of collection extended from 

 June 25 to July 8. 



In view of the difficulties experienced the past season in hatching 

 eggs of the mackerel, Dr. J. P. Moore was employed to make a special 

 study of the development of the egg, with the view to suggesting some 

 practical improvements in the hatching methods. 



The following are the most important of the hatching processes 

 experimented with : Increase of density from the normal 1.0224 to 1.0252 

 by the addition of salt; floating box in supply tank; McDonald jar 

 with supply covered; inverted cod-jar with tidal flow; jar with bottom 

 feed and cheese-cloth top; jar containing salt water to which new water 

 was added from time to time; and, finally, the tidal-box system. There 

 appeared to be no marked improvement in any of the methods over that 

 of the tidal-box system, which last year hatched over 70 per cent in 

 one instance. As far as could be observed the difficulty appeared to be 

 with the egg and not with the hatching apparatus. Many fish were 

 found to be spent soon after the commencement of operations, and eggs 

 Avere found in all stages of development throughout the season. At the 

 end of July fish were noticed that had not yet spawned. There is no 

 difliculty in fertilizing the eggs, as all taken appear to be impregnated. 



It has been stated in previous reports that the eggs lacked sufficient 

 vitality to produce healthy fry, and it was thought that the good 

 eggs were given up while the fish were endeavoring to escape from the 

 net. Nothing occurred during the season to disprove this, but fi'om 

 further investigations it would seem that the greater number of the 

 mackerel spawn offshore. This view is substantiated by the condition 

 of the fish when taken, and by the fact that only with ofi'shore winds 



