204 BRITISH FRESH-WATER FISHES 
returning to the river to spawn, for by the act of spawning 
the fish ceases to be a grilse. 
Some light has been thrown by these observations upon the 
question whether salmon always return to their native river. 
The answer, so far as it has been received, is ‘‘ Generally, but 
not invariably.” Mr. Calderwood gives eighteen instances * 
of fish recaptured in the same river after the lapse of at least 
one season, and four in which fish were recaptured in other 
rivers. Only one of these had travelled to a distant river— 
namely, one taken as an unspawned female in the Spey at 
Fochabers on December 14th, 1896, marked, returned to the 
water, and retaken as a kelt on February 22nd following in 
the Aberdeenshire Dee. The mouths of these two rivers are 
ninety miles apart. 
Out of sixty-seven instances of fish captured twice within 
the same river at intervals varying from 35 to 137 days, 
without having revisited the sea in the interval, in sixty-two 
cases there was a loss of from 2 lb. to } lb. in weight, and in 
five cases only no change in weight was recorded. This bears 
on the vexed question about salmon feeding in fresh water, 
and, contrasted with their proved rapid increase in salt water, 
seems nearly conclusive against their taking nourishment after 
they have quitted the sea. 
Fish culture has made considerable advance in this country 
during the last half-century, and salmon hatcheries have been 
Artificial Crected in various parts of the United Kingdom. 
incubation. Tt would be foreign to the purpose of this book to 
enter upon a technical dissertation upon the management of 
these ; but it may be remarked that fish of the Salmon Family 
* Nineteen in all, but in one of these the fish, an unspawned male of 
304 lb., was handled in spawning operations unsuccessfully, marked, and 
returned to the Spey at Fochabers in December, 1896. In March, 1897, 
the same fish was retaken in the Deveron weighing only 28 lb., and was 
still not fully spent. It is probable the fish had been injured in the 
attempt to use him for the hatchery at Fochabers. 
