528 Memoir Sears Foundation for Marine Research 



time) with darker wavy crossbars, especially on the upper and lower corners. The 

 pectorals, pelvics, and anal are some shade of pink, orange, or crimson, the pec- 

 torals and pelvics dusky; the first ray of the pectorals, pelvics, and anal is white 

 or cream-colored, conspicuously edged rearward with black. Fingerlings up to 5 or 

 6 inches or so are more or less conspicuously marked on the sides with a series of 



7—1 1 (av. 9) dark, vaguely outlined 

 Table XI. Dorsal and Anal Rays of S.fontinalis* crossbars or blotches, known as 



No.ofrays 9 10 11 12 13 14 parr marks. 



Dorsal, no. of specimens . — — 40 120 50 i The young Brook Trout that 



Anal, no. of specimens... i 47 123 38 — — are destined to move out into salt 

 • After Wilder, y8: 186, tab. 8. water cannot be distinguished at first 



by their color from those that are 

 to remain in fresh water. This continues true in some localities until after they have 

 actually left the stream mouths, for example on the coast of eastern Maine (see Study 

 Material, p. 525). In other localities, however, as in the Moser River, Nova Scotia, 

 the sides of the future Salters, now known as "smolts" in conformance with salmon 

 nomenclature, have turned partially silvery, through the deposition of guanin crystals, 

 by the time they are ready to migrate downstream, although they still show their parr 

 marks. It seems that this difference in color between different populations is associated 

 with the age at which they move out into brackish water, for while some of the Maine 

 Salters (p. 525) do this as early as their first summer, and many by their second sum- 

 mer, the smallest sea-run Moser River fish were in their third summer. In any case, 

 the development of the Salter coloration evidently is a reversible process, for Wilder 

 found that Moser River smolts whose sides had already turned partially silvery lost 

 the silver if they were retained in fresh water (7^: 173). 



After the Brook Trout move out into brackish or salt water, their sides tend to 

 become increasingly silvery, the greenish-blue-to-bottle-green marbling of their upper 

 parts becomes obscured, their bellies become paler, and their pectoral, pelvic, and 

 anal fins lose color. In extreme cases, their sides may turn as silvery as those of Atlantic 

 salmon, with the pale yellow spots and crimson dots showing only faintly and the 

 marblings hardly visible. Their pelvic and anal fins are white, perhaps faintly tinged 

 with pink, and show no trace whatsoever of the black edging on the first ray that is 

 so conspicuous on freshwater fish. But the dark wavy markings on the dorsal fin and 

 on the upper part of the caudal continue to be conspicuous. 



The published descriptions of the color of sea-run fontinalis have in most cases 

 been based on specimens of this sort, but the individual Salters may vary widely in 

 color, even though caught side by side. One of the Prince Edward Island specimens 

 listed above is pale (Fig. 128), although its sides, after preservation in formalin, now 

 show no trace of silver. On another, however, the back and the upper part of the 

 sides are much darker, the marblings, pale spots, and crimson dots are much more 

 evident, as are the dark markings on the dorsal and caudal fins, the lower part of 

 the sides is gray, and the first ray of the pectoral, pelvic, and anal fins is outlined as 



