180 REPORT OF COMMISSIONER OF FISH A>'D FISHERIES. 



as that of rlie brook trout. Their egg^s are some^vhat larger than those 

 of the latter fish, but they are handled in the same way. the i>rogress 

 of incubation is similar, and the fry are fed on the same materials. 



Small numbers of the European sea trout or salmon trout [Sahno 

 trutt^) have also been propagated at Craig Brook and other stations, 

 and have been reared to full matuiity in ponds. 



The fish called the Swiss lake trout, European charr. or saibliug 

 {Salrelinm a1pinug]^liaiS been propagated on a small scale from eggs 

 taken from i>ond fish, which in turn were hatched from eggs sent from 

 Switzerland. This species is similar to the brook trout and other 

 native eharrs, and its eggs are subjected to the same methods. 



The representative of the saibling found in certain Xew England 

 lakes, known as the Sunapee trout, or golden trout [Salrelinus alpinus 

 aureolus), has also received some attention from fish-culturists. 



The Michigan grayling (Thyinallus ontariensis) is naturally found 

 only in certain streams in Michigan, although the type specimen was 

 said to have come from Lake Ontario. It is one of the most attractive 

 and game of fresh-water fishes, but is rapidly approaching extinction, 

 owing to excessive fishing and the pollution of streams, which have not 

 been counteracted by artificial propagation. The Montana grayling 

 {Uiymalhi-^ ontariensis montanus) inhabits a limited area in the head- 

 waters of the Missouri Eiver and is very abundant in some streams. 



The Arctic grayUng {ThymaUus signifer )is fotmd from the Mackenzie 

 Eiver westward through Alaska and north to the Arctic Ocean. The 

 31ichigan grayhng rarely weighs 1^ pounds, and the average weight is 

 only half a x>ound : the northern si>ecies is somewhat larger. 



Although thcK-ultivation of the grayling was begun as early as 1874, 

 it was never regularly or extensively conducted. Spawning in Michi- 

 gan occurs in April, and the eggs are normally laid in gravel beds in 

 clear, cold streams. The number of eggs taken from a single fish varies 

 from 3,000 to 4,000. The same methods of culture pursued with the 

 brook trout are applicable to the grayling. In water having a tempera- 

 ture of 50- to 60- F.. the incubation period is 14 to 20 days. 



THE LAKE HERRING AND OTHER WHITEFISHES. 



While the common whitefish is the only member of the tribe that has 

 received much attention from fish-culturists, it is probable that several 

 other 5i>ecies of whitefi-sh will in time be extensively xjropagated. The 

 lake herring { Argyrosomus artedi) has already been artificially hatched 

 to a limited extent at Put-in Bay station, and the long-jaw or bloater 

 {Argyrosomus prognathus), the bluefin or blackfin A. nigripinnis), the 

 tullibee lA. tullihee), and others will doubtless become the subjects of 

 fish-cultural work in certain lakes. The eggs of all these fish can be 

 hatched by the same methods as are used with the common whitefish, 

 but the spawning seasons differ. 



The lake herring is readily distinguished from the common whitefish 

 by its smaller size, projecting lower jaw, long and numerous gdlrakers, 



