Reproductive traits of the intertidal sea star Anasterias antarctica (Echinodermata: Asteroidea) from the Beagle Channel, Argentina

Noble hosts: effects of internal parasites on the physiology of an intertidal brooding Sea-star

“…The Beagle Channel (55°S, 68° W) connects the Pacific and Atlantic oceans at their southernmost extreme. Its waters are characterized by their low salinity due to the profuse drainage in both margins; small streams and rivers that descend from melting and glaciers towards the sea keep surface values of salinity below 32 UPS (Fraysse et al, 2021;Iturraspe et al, 1989;Pérez et al, 2008). Anasterias antarctica individuals were collected from the rocky intertidal of Ensenada Zaratiegui bay (Beagle Channel, Fig.…”

“…All individuals were anaesthetized by immersion in MS-222 (ethyl 3-aminobenzoate methanesulfonate acid salt, 98 %, Sigma-Aldrich) 1 % in seawater, for 45 min (O'Neill, 1994), before dissection (Fraysse et al, 2021). During dissection, the following variables were registered: sex (if possible), brooding or nonbrooding condition in females, castration (if gonads were no present), and presence of the coelomic parasites, D. argentinensis (Fig.…”

“…Females brood the lecithotrophic embryos on the oral surface over the mouth for eight months, from April to November. (Fraysse et al, 2021;Pérez et al, 2015;Pérez et al, 2017), and do not feed during this period (Gil & Zaixso, 2008;Gil et al, 2011). A recent study on their reproductive cycle showed that females undergo two consecutive and different annual cycles (Fraysse et al, 2021).…”

“…(Fraysse et al, 2021;Pérez et al, 2015;Pérez et al, 2017), and do not feed during this period (Gil & Zaixso, 2008;Gil et al, 2011). A recent study on their reproductive cycle showed that females undergo two consecutive and different annual cycles (Fraysse et al, 2021). The first cycle corresponds to the production of large oocytes (approx.…”

“…The first cycle corresponds to the production of large oocytes (approx. 1 080 µm) that, once fertilized, will develop into a modified lecithotrophic brachiolaria larva, which will be retained and brooded (Fraysse et al, 2021). In the second consecutive cycle, the gonadal maturation produces many smaller oocytes (approx.…”