Age and growth variability of the yellow clam Mesodesma mactroides Reeve, 1854 in two populations of Argentina: implications under climate change

RISOLI MARIA C.,; BALDONI, A.; GIMENEZ JULIANA,; LOMOVASKY BETINA J.,

CANADIAN JOURNAL OF ZOOLOGY

NATL RESEARCH COUNCIL CANADA-N R C RESEARCH PRESS

Lugar: Otawa; Año: 2020 vol. 98 p. 481 - 494

0008-4301

Morphometric relationships, age and growth rates of the yellow clam Mesodesma mactroides Reeve, 1854 were compared in two populations of Argentina: Santa Teresita (36°32′00′′S) and Mar del Plata (37°57′52′′S). Santa Teresita clams were heavier (shell and soft parts) than the ones from Mar del Plata. Mutvei?s-stained cross-sections and acetate peels revealed an internal shell growth pattern of well-defined slow-growing translucent bands and alternating fast-growing opaque bands. The major translucent bands (clusters) representing external rings were formed mostly during October in Mar del Plata and Santa Teresita coinciding with gonadal maturation processes and spawning. These data confirm the annual formation of translucent bands in this species. Comparison of growth parameters showed a higher growth rate k and lower maximum age in Mar del Plata (8 yr.) than Santa Teresita (9 yr.). These could be triggered by differences in salinity variation due to the influence of the Río de la Plata Plume between localities, which is strongly linked to climate variability. Considering these events, e.g El Niño Southern Oscillation (ENSO), are more intense and frequent in the last years, it could be expected changes in the growth rate of Santa Teresita population, being more vulnerable under climate change