Validation of the Use of Scales of Brook Trout, Salvelinus fontinalis, for Age Determination

Abstract

T HE brook trout or speckled trout, Salvelinus fontinalis (Mitchill), has long been a favorite of both the angler and fish-culturist in America. may be stated safely for northeastern United States that more money and effort have been spent propagating, planting, and managing this sport fish during the last 75 years than for any other. In consequence, there exists for the species a voluminous literature, both technical and popular. Information is scant, however, on the growth rate of brook trout in wild populations. The state of such knowledge up to and for some years following 1900 is exemplified by Agassiz' oft-quoted nineteenth century reply to a query regarding the age of large brook trout from Rangeley Lake, Maine: . .. no man living could tell, they might be 10 to 200 years old (Kendall, 1914: 90). Information on the growth rate of brook trout was still crude for the first three decades of the twentieth century: It takes perhaps ten or fifteen years to produce a four or five pound trout under natural conditions. Who actually knows? (Kendall and Dence, 1929: 272). About this time, however, the first results from using scales for age assessment in brook trout were published (Kendall and Dence, 1927), but these are of questionable reliability. Since 1932 only enough knowledge of age and growth in the species has accrued to show that scales might be used for age determination, to confirm the value of data on growth rate in management, and to establish the need for more information on these and related lines of study.