THE LIFE-HISTORY OF THE SALMON. 285 



return. During development of the reproductive organs the 

 scales suffer deterioration — producing the "spawning mark." 



Though the Salmon is chiefly known as a freshwater fish, 

 yet it is as much, if not more, an inhabitant of the sea, and to 

 this habit there can be little doubt its safety is mainly due. It 

 seeks the fresh waters for the most part to reproduce its species, 

 for it does not enter them to feed. In the stomach of those 

 caught off Tentsmuir and at the entrance to the Tay, as already 

 stated, Sprats, Herrings and Sand-Eels occur, but after they 

 have fairly entered fresh water no food of note is taken. 



Whilst the Salmon feeds freely in the sea it also becomes a 

 prey to larger forms, such as Seals, toothed Whales of various 

 kinds, even a Cachalot occasionally taking one. Groups of 

 Seals at the estuaries of Salmon-rivers, such as the Tay, cause 

 considerable loss to the tacksmen, who wage war againt them. 

 Ca'ing Whales {Globiocephalus melas) appear to search for 

 Salmon in their course round the various stake-nets in a bay, 

 and the fishermen think the Porbeagle Sharks and Porpoises 

 captured in these nets likewise seek the Salmon, but no frag- 

 ments of Salmon have ever occurred in either at St. Andrews. 



As a rule Salmon are captured in the sea by stake-nets (or 

 fly-nets) on sandy beaches, and by bag-nets- off rocky shores. 

 The principle in both is similar. At St. Andrews the stake-net, 

 in use for generations on the west sands,* consists of a vertical 

 leader (a single stretch of net) run out from the shore, supported 

 on stakes or poles, and terminating seawards in two chambers ; 

 the first opening freely on each side of the leader, but otherwise 

 closed, so that a fish passing in either direction parallel with the 

 shore is guided into it, then into the second chamber by a 

 narrow defile, and lastly into the " trap " by a similar defile. 

 Entrance is easy, but the acuteness of the fish is seldom 

 sufficient for escape. The retiring tide carries many other 

 fishes into the netted chambers, such as Flounders (P. flesus), 

 young Turbot, Brill, Plaice, Sturgeon, Dog-Fishes, Frog-Fishes, 

 young Sharks and Skate; whilst Porpoises, young Ca'ing Whales, 

 or even a Regalecus and a Great Northern Diver are some- 



* A water-colour drawing of which (by E. M.) is in the Gatty Marine 

 Laboratory. The net is usually erected in May after the heavy surf of early 

 spring disappears. 



