Exploring the causes of differences in growth rate of the Patagonian scallop Zygochlamys patagonica along its commercial bed distribution in the SW Atlantic

Abstract Comparisons of maximum age and growth rates of the Patagonian scallop Zygochlamys patagonica from seven beds across most of its distribution range (39°30′S to 46°47′S; SW Atlantic) were studied in relation with physical parameters and Chlorophyll a concentration. The estimated maximum age varies between 19 and 25 years across different beds. Differences in the von Bertalanffy parameters were found between beds located at 39°37′S (San Blas) and 42°15′S (Valdes) increasing H ∞ , and decreasing k from North to South. These latitudinal trends are correlated with a meridional difference of spring Chl a concentration and the timing of the thermocline decreasing from North to South. Thus, with the available information we hypothesize that differences in scallop growth parameters between beds are due to hydrographical processes that influence primary productivity.