Figure 2. (a) A 62 mm (shell length) age 11 ocean quahog, Arctica islandica, released after marking in 1978 off Long Island, and recovered 6 September 1983 before that year's annulus had formed; (b) hinge tooth showing 11 annuli; (c) photomicrograph of the valve margin with each annulus identified by the year of it's formation.

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