54 THE LIFE OF THE SALMON 



female grilse bears a much smaller proportion to the 

 weight of the body of the fish than is the case in 

 female salmon. In this respect grilse differ from 

 salmon, both large and small, where the proportion is 

 practically constant at 3*02. In grilse it is only 

 1*95 during the months named. In terms of 100 

 this percentage in grilse and salmon respectively is 

 as 64 to 100. As the season advances, the degree 

 of development of the genitalia steadily increases, 

 but the proportional development is later in the 

 grilse than in the salmon, or commences later, 

 although both grilse and salmon become fully ripe 

 at about the same time. These particulars were 

 clearly deduced by Archer * from the observations 

 referred to. 



After leaving the river, it is clear that the grilse 

 can and does travel to fairly distant points on the 

 coast at considerable speed. A Deveron grilse kelt 

 marked at the mouth of the river (Duff House) was 

 found in a coast net 50 miles distant (Port Errol) 

 in 88 days. A similar recapture was made in 109 

 days. Another Deveron grilse which had travelled 

 70 miles to Cove, south of Aberdeen, in 122 days 

 was found on recapture to have gill maggots 

 (Lerneopoda salmonea, Linn.) still attached. The 

 fish was sent to me in Edinburgh with the mark 

 in situ, and I had the maggots carefully diagnosed 

 by Mr. Scott, a specialist in the lesser Crustacea 

 and a naturalist on the staff of the Fishery Board. 

 It is as yet uncertain how long those fresh water 

 parasites can remain attached to the gills in sea 



* Fourteenth Annual Report Fishery Board for Scotland, 

 Part II. p. 9 et seq. 



