| Summary: | The distribution in northern Norway of the Iceland scallop, Chlamys islandica (O. F. Müller) has been mapped (Fig.s 3-7). The species is mostly found in the inner of fjords having one or two sills, 3-15 m deep inside the enthrance. The beds are mostly located on hard bottom with sand, gravel or stones in l0-60 m of depth. A few small scallops are sometimes found on the outer side of the sill together with a number of larger empty shells. - It is supposed that the Iceland scallop is very sensitive to changes in temperature. In some fjords scallop beds existing some years ago have been extinguished, probably because of a sudden rise in temperature. The species is sexually mature at a shell breadth of 30-45 mm, and at a supposed age of 3-5 years. The sexes are separate, spawning taking place in July-August. The breadth of all scallops has been measured in 5 mm groups, representative size distributions being worked out for various localities. The sizes vary from 10 to 105 mm, with the peaks at 45-90 mm (Fig.s 10-11). Distinct growth zones have been found (Fig. l) and on the assumption that the zones represent the annual growth, age distributions have been worked out (Fig. 12). In all localities there is a large number of year classes, 2-14 or more years, the bulk of the scallops being 8 or more years. Growth curves have also been constructed, the annual growth being estimated to 5-10 mm the first 7 years (Fig. 13). Later the growth decreases. Weight analyzes have also been made. Scallops of commercial size (60 mm or more) range in total weight from 30 to 130 grams, the meat weight (adductor muscle plus gonad) from 5 to 30 grams (Fig.s 14-15). It is supposed that the scallop beds found may support a minor commercial fishery.
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