Reproductive seasonality and histochemical profile in Brachidontes rodriguezii ( D´Orbigny, 1846) from the Southwestern Atlantic Ocean

TORROGLOSA, M. E.; OJEDA, M.; DI STEFANO, V. ; GIMÉNEZ, J.

Cambridge

Congreso; 7th Congress of The European Malacological Societies; 2014

Brachidontes rodriguezii  has a wide distribution along 1500 km of the Argentinean coast from Buenos Aires to Patagonia. Is the most abundant species in the intertidal benthic community associated to rocky shore. In the last years, because of the introduction of hard substrates as docks, sandy beaches became a new habitat for this species. The reproductive cycle was studied, over a period of two consecutive years, through analysis of gonadal samples. Individuals were sampled monthly at the hard substrates of Buenos Aires province, in the north limit of it distribution. Stage of gonadal development and oocytes size frequency in females of B. rodriguezii was used to estimate the reproductive events. The presence of previtellogenic, early vitellogenic and late vitellogenic oocytes, were found all the year. With a high frequency of mature oocytes during the late Spring and early Summer. Spermatogenesis was continuous throughout the year. The reproductive season in the sampled locality extended from December to February (austral summer). During summer, histochemical characterization shows the presence of neutral lipids in oocytes and the gonadal connective tissue. After spawning, gonads of  B. rodriguezii present oocytes under atresia and a lower concentration of lipids in the connective tissue. The reproductive seasonality was linked to changes in water temperature and photoperiod. These results suggest that B. rodriguezii has a simple yearly cycle of gamete production.