Reproductive cycle and gonad development of the Northern Argentinean (Bivalvia: Mesodesmatidae)

Marko Herrmann (1, 2) , José E. F. Alfaya (2) , Mauro L. Lepore (2) , Pablo E. Penchaszadeh (2) , Jürgen Laudien (1)

1 AWI - Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung = Alfred Wegener Institute for Polar and Marine Research = Institut Alfred-Wegener pour la recherche polaire et marine
2 MACN - Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia' [Buenos Aires]

The reproductive cycle and gonad development of the yellow clam was studied over a period of 24 months (January 2005–December 2006) at the Argentinean sandy beach Santa Teresita. Histological examination of gonadal tissue revealed that sex ratios did not significantly deviate from the proportion of 1:1 and no case of hermaphroditism was found. The reproductive cycle of followed an annual cyclicality, which was significantly correlated to monthly mean sea surface temperatures (SST). Oocytes showed highest abundance in winter, indicating a process of gonadal development and sexual maturation. The mean oocyte size decreased significantly during spring. Modal oocyte sizes decreased significantly during winter and late spring of each year, suggesting spawning events. The condition index was not useful in describing the annual reproductive cycle of . Ash-free, shell-free dry mass was chosen to detect the condition of the specimens, and this significantly correlated with monthly mean SST and the gametogenic cycle. Annual recruitment patterns during summer–autumn indicated a 3-month-long planktonic phase of . The reproduction cycle and gonad development of showed only weak differences between data from the present study and those collected 40 years ago.

Mots clés: Yellow clam; Histology; Condition index; Ash-free; shell-free dry mass; Oocyte size and abundance

Marko Herrmann, José E. F. Alfaya, Mauro L. Lepore, Pablo E. Penchaszadeh, Jürgen Laudien. Reproductive cycle and gonad development of the Northern Argentinean (Bivalvia: Mesodesmatidae). Helgoland Marine Research, 2009, 63 (3), pp.207-218. ⟨10.1007/s10152-009-0150-2⟩. ⟨hal-00535189⟩