INTRODUCTORY 25 



Calderwood's real view, namely, that the cstuarine trout is a variety, 

 but not a species, of trout. He had just written, however, in adverting 

 to the estuarial habits of the sea-trout : — " Many common brown trout 

 are to be found under [)recisely similar conditions and feeding on a 

 purely marine diet; in the estuary of the Tay near the Tay Bridge, I 

 have found large silvery common brown trout with freshly swallowed 

 herring as well as much digested herring in their stomachs and intes- 

 tines." It is not very clear whether Mr. Calderwood means to 

 distinguish these " common brown trout '" from " the established tidal 

 variety." 



The late Mr. Hamish Stuart, in his well-known book on " Lochs 

 and Loch Fishing," wrote much that was suggestive, and something 

 that has a bearing on this discussion. In the Howmore River in South 

 Uist he states that he distinguished the sea-trout and the bull trout. 

 '■ The very first cast I ever made in the river," he wrote, " I rose a large 

 bull trout, with my second cast I rose, hooked, and lost an criox of 

 perhaps 12 lbs." In the river he also found, he says, "a few small 

 yellow trout, of a particularly pretty colour, fine flavour, and shape, 

 peculiar to the river." Then he adds, " There are two other kinds of 

 fish in this river, namely, the estuary, slob or tidal trout, and a remark- 

 ably beautiful hybrid — apparently either between the said tidal trout 

 and the sea-trout, or between the latter and the common trout .... 

 It reaches occasionally the weight of i lb., but is rarely over, and 

 generally under, h lb. This fish does not appear to spawn, but is 

 numerous." And of the Strome Dcarg, the connecting semi-artificial, 

 semi-tidal link between Loch Hallan. also in South Uist, and the sea, 

 he writes : — " Besides sea-trout this salt-water river is frequented by a 

 species of yellow trout with extremely large spots," which he attributes 

 generally " to the slob or tidal variety." He concludes : — "As the 

 Strome is frequented by yellow trout originally from Loch Hallan and 

 other lochs, the peculiarities of its environment have practically 



