76 BULLKTIN OK THE BUREATT OK KISHERIES. 



The experiinent was discontinued after 4 days of l.(J()l water. At this tiin' 

 1 lish was dead, the other feeble. 

 JExperii/iriif.^ 'i7 'IikI ',^. 



New ^'urk. Aj))-!!. VM^U. Six tonicod (MicnHjiuInx tomcdij) and ]n wiiilcr 

 floundiM-s (I's, ii(l(jjilriif<ii)i<-/i-K (i/iie/w'ai/ms) were used, respectively. With cadi 

 species a ei miparisoii was made between the effects of fresh water and of tin- 

 siielitiy saline water. With the former species the gain was slight (a})out I 

 per cent in each case, though here slightly less in the fresh water), and e\eii 

 the transfer to fresh water seemed to have little or no harmful effect. Mo-i 

 of the fishes lived until killed by fungus, from 1 to 4 weeks later. 



In the case of the flounders there was a gain of about 5 per cent in 1 day in 

 each sort of water. In fresh water, however, the fishes died in 2 days, in tlir 

 slightly saline water in from 4 to 5 daj's. 



Weight determinations were likewise made in the <-ase of certain fresh-water 

 fishes transferr(>d to salt Mater. 

 Eeperiiinnt ','■>■ 



New York, .\prii. liM)."). Three catfishes {AmAurux ii,luhmi!<)Y>y\\ into salt 

 water (1.01U-|-). Average decrease for all. 8.3 per cent in IT liours: a\-eiae'e 

 decrease for two, 1.").8 per cent in 48 hours. 



One of the fishes, being put back into the l.ool tank at the end of IT h()ui>. 

 regained in -1 days nearly all that it had lost. Those in salt water were \iry 

 feeble at the end of the second day. 

 Ei-prriment oO. 



New York, April, IHO.l Eight rudd {Lrnr;s,;,>< erijthrophtl,,,! mus) had l..>i 

 over 4 per cent at end of first day in water of density l.Ull. All dead. 

 It seemed particularly worth while to test the changes of weight in the case nf 

 certain fishes which may survive abrupt change from fresh to salt water, and which 

 in nature inhabit both. Hence the next six expei'iments. 



EqM'llHrut 01. 



New York, May, 1!»05. Five white perch {21<imne (uncrtcand), taken from a 

 fresh-water pond, lost on the average 4.7 per cent during the first day aftei- 

 the change to salt water (1.012). During the preceding 2 days the loss from 

 waste had been only 2.2 per cent or slightly over 1 per cent per day. The fish 

 all appeared perfectly well after the change. 

 E.rpei'imetif 52. 



Five other specimens of the white perch (taken from salt water) were trans- 

 ferred to fresh. The average weight of these remained almost exactly sta- 

 tionary during the following day, after which the}' were not weighed. It 

 must be remembei-ed, however, that stationary weight implies a gain sufficient 

 to cover the loss thi'ough waste. Nevertheless, such a result was not what I 

 had anticipated, and this experiment is one of the two among the entire New 

 York .series whose results are not entirely in harmony with the others. 

 The case of the chinook salmon {0>iri>/'/i///u'/iiis tscliiiir^/tKcha) is yet more 

 instructive. 



Er.periiiient oJ. 



New York. March and April, I'.tu.".. Six specimens which had been reared 

 in fresh water at the New York Aiiuarium were chanued abruptly to salt 



