5 1 6 Memoir Sears Foundation for Marine Research 



Under hatchery conditions, incubation of the eggs of freshwater Arctic Charr 

 has been found to occupy between 60—70 days at a temperature of 40° F (4.4° C) 

 {in 61: 847). Eggs that were artificially fertilized at Baldernas in Dalsland, Sweden, at 

 the end of October did not begin to hatch until the beginning of the following March 

 (Malm in 61: 847). In the northwestern Hudson Bay area "the eggs are still visible 

 at break-up [of the ice] in the following spring, probably hatching soon after open 

 water appears" (Sprules, 62: 12). 



Migrations. The migratory schedule of the sea-running populations of alpinus 

 consists of a downstream movement early in summer out into brackish or salt water; 

 a sojourn there until late summer or early autumn, during which time they make 

 most of their year's growth; a return movement in late summer or early autumn to 

 fresh water, with the immature fish participating as well as those that are maturing 

 sexually; and a sojourn in fresh water until the following June or July, the early part 

 of which covers the spawning period. 



Arctic Charr of Frobisher Bay, Baffin Island, are reported as carrying out their 

 first downstream migration after they have spent 5—7 winters in fresh water, those 

 of Spitsbergen migrate after 2, 3, or 4 years, and those of Novaya Zemlya after 3 or 4 

 years. Those of northeastern Labrador, however, may descend after only 2 or 3 years to 

 judge by the presence in the bays there of fish not more than three or four inches 

 long, sometimes several miles away from the nearest spawning stream {y2: 132). 



The spawning migration into fresh water takes place between late July and the 

 last half of September, according to locality, with the precise date governed to a con- 

 siderable degree by the height of the water in the streams. Heavy rainfalls, for example, 

 swell the streams so that Arctic Charr can ascend falls that would otherwise bar their 

 passage, for they do not have the leaping powers of salmon and often are "stopped 

 by falls with a vertical drop of not more than a foot" (Weed, y2: 132). For this same 

 reason also, their ascent is much easier during periods when the tides are at their 

 highest (spring tides) than when they are at their lowest (neap tides). 



Along Southhampton Island they congregate at the head of tide by late August, 

 to ascend either with the first spring-tide period or during the first heavy rainfall, which- 

 ever comes the first. In Ungava Bay, in both the George River region and the Kok- 

 soak River, Arctic Charr enter fresh water by the latter part of July in most years and 

 during the early part of August in others, with the height of the run lasting from 

 eight to fifteen days (Turner in 16: 99, ftn.). In the vicinity of Nain, on the coast of 

 northeastern Labrador, in the one year of record (1928), they had entered the streams 

 by August. In the Sylvia Grinnell River, Frobisher Bay, Baffin Island, the mouth 

 of which is barred to them by falls that are passible by fish only at the time of spring 

 tides, the fish were ascending by the last week of July, in 1950; in 1948, however, few 

 ascended until August. In western Greenland they have been described as ascending 

 from late July through August until the streams freeze once more; in northeastern 

 Greenland (Denmark Bay) the run continues from August until about mid-September, 

 when the local rivers freeze ; and the run covers about this same period in Novaya Zemlya. 



