Gametogenesis, seasonal reproduction and imposex of Adelomelon beckii (Neogastropoda: Volutidae) in Mar del Plata, Argentina

Abstract

Adelomelon beckii (Broderip, 1836) (Neogastropoda: Volutidae) is endemic to the western south Atlantic coast. It inhabits sandy bottoms in waters between 40 and 70 m deep and is one of the largest top benthic predators found in Mar del Plata, Argentina. The present study describes gametogenesis and the reproductive cycle of this species. Oocytes developed in close association with follicle cells, which appear to play a role in yolk synthesis and oocyte resorption, providing the key functions of phagocytosis and intracellular digestion of degenerating oocytes. Spermatogenesis resembles that reported for other volutids. The reproductive cycle of A. beckii in Mar del Plata was studied over a period of 2 yr (September 2004 to August 2006). Gametic emission in males continued throughout the year while females showed 2 spawning periods: one during spring (September-November) and another during autumn (March-April). In females, this semi-annual pattern appears to be related to the seasonal variation in seawater temperature, coinciding with observations made in other volutes. In males, there was no relationship to variation in seawater temperature, an unusual pattern for a species from a temperate region. Imposex was described for the first time in this species. These data constitute baseline information for establishing appropriate and biologically based management and conservation strategies for this overexploited gastropod species.KEY WORDS: Adelomelon beckii · Gametogenesis · Reproductive cycle · Volutidae · ImposexResale or republication not permitted without written consent of the publisher

Age, growth and mortality in the giant snail Adelomelon beckii (Broderip 1836) on the Argentinean shelf

“…2). Shell-free wet body mass ranged from 170 to 2720 g and was related to SL by: log SFWM ð Þ= −4:523 + 3:025* log SL ð Þ; g−mm; r 2 = 0:835; N = 202 SL was linearly related to SG, the distance from the apex along the growth trajectory to the aperture of the shell, by: Overall sex ratio is 2.07 (see Arrighetti and Penchaszadeh, 2010a).…”

“…Salzwedel, 1980). We presume the same cause for the summer growth band in A. beckii, because it does not show in the early, most likely pre-maturity years, and it coincides with the time of reproductive activity (Arrighetti and Penchaszadeh, 2010a).…”

Reproductive cycle in an imposex-affected population of Olivancillaria deshayesiana (Gastropoda: Olividae) from Mar del Plata, Argentina

“…This pattern may be related to an increase in seawater temperature and photoperiod, which are important environmental factors regulating gonadal development and spawning in many gastropod species (Fretter & Graham 1994, Giménez & Penchaszadeh 2002, Cledón et al 2005, Bigatti et al 2008, Arrighetti & Penchaszadeh 2010. Males exhibited a pronounced resting period from summer to autumn (February to April), in accordance with a decrease in these variables.…”

“…However, this pattern is unusual in males of other Neogastropoda species, whose testes seem to produce mature sperm year round without a resting period, e.g. the volutids Zidona dufresnei (Gimé nez & Penchaszadeh 2002), Adelomelon brasiliana (Cledón et al 2005), and A. beckii (Arrighetti & Penchaszadeh 2010) in Mar del Plata, Odontocymbiola magellanica (Bigatti et al 2008) andA. ancilla (Pen chaszadeh et al 2009) in Golfo Nuevo, and the nasarid Buccinanops cochlidium in Golfo San José , among others.…”

Vitellogenesis and changes in lipid and protein content of oocytes of Trophon geversianus (Neogastropoda: Muricidae) in Golfo San José (Chubut, Argentina)

“…These events, in turn, coincided with rises in the mean surface water temperature and a 13 light-hour photoperiod, agreeing with Cumplido et al (2010), who observed that T. geversianus females maintained in laboratory conditions began spawning when the photoperiod reached 13 light hours. It has also been reported by histological methods that spawning events in other template water marine gastropods are induced by changes in water temperature (Giménez and Penchaszadeh 2002;Arrighetti and Penchaszadeh 2010).…”