Figure 1. (a) A 110 mm (shell length) age 125 ocean quahog, Arctica islandica, released after marking in 1978 off Long Island, NY, and recovered 6 September 1983 before that year's annulus had formed; (b) enlargement of the marked area; (c) photomicrograph of the valve margin showing an annulus formed soon after marking (arrow) and four additional annuli.

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