Age and Growth of Dogfish <i>Squalus acanthias</i> in British Columbia Waters

Abstract

Ages of dogfish have been determined from markings on the second dorsal spine by a technique that enables use of badly worn spines from relatively large fish to correct for the tendency to underestimate age. While the technique may have led to slight overestimation of age, particularly of dogfish from Hecate Strait, there is some corroborating evidence for the Strait of Georgia drawn from length-frequency distributions, sizes of fish in relation to reproductive stages, and assumptions about the average annual net uptake of mercury. It is tentatively concluded that the growth curve for females, expressed in terms of the von Bertalanffy equation, has parameters of K = 0.048, [Formula: see text], and t 0 = −4.88 yr. Parameters suggested for males are: K = 0.070, [Formula: see text], and t 0 = −4.70 yr. The implication emerging from these results is that females and males on the average take 23 yr and 14 yr, respectively, to reach maturity.