New perspectives on the growth and longevity of the European lobster (Homarus gammarus)

The natural rate of lipofuscin accumulation in an eyestalk ganglion was det ermined from microtagged European lobsters, Homarus gammarus, of known age, recaptured from the Yorkshire fishery (United Kingdom). This calibration, in combination with supporting data from shorter-lived astacideans (freshwa ter crayfish), was used to age wild lobsters from the fishery. A unique per spective of age-at-size in a clawed-lobster population was obtained, which circumvented some difficulties associated with conventional methods for est imating generalized growth and natural mortality. The exceptional ages atta ined by some of the largest lobsters (males: average 31 years, maximum 42 /- 5 years; females: average 54 years, maximum 72 +/- 9 years) are explaine d by ageing theory, indicate natural mortality rates, M, of 0.15 and 0.08 f or males and females, respectively, and point to the existence of an offsho re refuge. Age-at-size is highly variable: at least seven year-classes ente r the fishery at 85 mm carapace length. This limits resolution of annual co horts in size compositions, complicates development of recruitment indices, and may explain past size composition stability. The new age-length data s uggest potential selective fishing impacts and past early recruitment varia tions. The study highlights the need for age data in order to obtain accura te crustacean stock assessments.