54 REPORT OF COM.MhSHIONKR OF FISH AND FISHERIES. 



1890-91. 



All additional steam ]minii, as a reserve in ease of accident, Avas pro- 

 vi<l«;d. lu tlic iMontli of. Inly, 181)0, the obstruction rack was placed in 

 the dam to arrest the upward passajj;'e. of the adnlt salmon. A gate with 

 sheerbooms, for facilitating- the onward passage of drift timber on high 

 water, was introduced into the dam. I<'ive days were consumed iu re- 

 moving the saw logs, which had grounded in the seining area, but all 

 could not be cleared out, and the strong current incident to their pres- 

 ence being a barrier to siKu-essful operations in hauling, it became nec- 

 essary to use gill nets in the capture of the adult lish. Owing to the 

 construction of a dam in the river below the station and the operation 

 of nets by coiniiiercial lislierinen, the ascent of a great number of tisli 

 was hindered. 



The collection of tlie eggs was commenced September IG, 1890, aiul 

 the first hatching took place about the end of October, ICggs continued 

 to be taken until November IG, the total from 1,004 lemales amounting 

 to 5,800,000. Of these, 700,000 were delivered October 22 and November 

 5, 1890, to the Oregon tlsh (commissioners. The remainder were hatched 

 at the station and tlu^ fry placed in Clackamas llivcr and its tributa- 

 ries. The fry produced were 4,902,000 or about 95 per cent of the eggs 

 retained. 



In January, 1891, the hatching took place so rapidly that use had to 

 be made of the troughs of the improvised hatchery of the previous year, 

 to i)re\eiit suffocation among the fry. Hatching terminated in Febru- 

 ary, the fry having been liberated from week to Ateek, within a ri\'er 

 scojie of 3 miles, as they arrived at the age to begin to take food. 

 A])out 1,000,000 were released subseipient to March 1. In the mol^ths 

 of May and June, 1891, the rack and tra])s Avere again overhauled and 

 l)ut in i)ositioii for the operations of the coming season. 



Aquaria at Crxtual STArrox, Washixctox, D. C. (W. P. Skal, ix chargk). 



1889-90. 



In July, 1889, a new hot-air engine, equipped witli vulcanized rubber 

 pump and piping, was introdu(;ed for circulating the salt water, the 

 brass piping being laid aside. IJy February, 1890, the water was ren- 

 dered so clear by means of filters that all objects could be distinctly 

 seen. The salt water lost by leakage was made up by supi)lies produced 

 at th(i station by dissolving Turk Island salt in filtered water at the 

 ])roper density; 1,000 gallons of sea water from Chesapeake Ba.y were 

 furnished by the steanuu' Fish JIaich: 



Collecticnis of salt-water objects were received throughout the year, 

 prin(;ii)ally from Woods IIoll Station, some being received from (Jlou- 

 cester Station, Mass., and others from Portland, Me., and the N<'w Jer- 

 sey coast. Fresh-water specimens were derived from the lish ponds, 



