FISHERY BULLETIN: VOL. 82, NO. 1 



FIGURE 6.— (a) Optical photomicrograph (compound microscope) of an acetate peel at a notch-mark in a 100.3 mm long 

 ocean quahog,Arctua islandica, about 110 yr old recovered on 9 September 1980. Note two annual increments of growth 

 formed laterally beyond the notch-mark, estimated to be 0. 1 mm (scale bar = 1 00 /urn), (b) SEM photomicrograph of the 

 same specimen (scale bar = 100 fira). The penetration of epoxy medium corresponds to the marking event, (c) Tran- 



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