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

FRAYSSE CINTIA; BOY, CLAUDIA C.; PÉREZ, ANALÍA F.

MARINE BIOLOGY

SPRINGER

Lugar: Berlin; Año: 2021

0025-3162

Sea stars display diverse reproduction strategies and development patterns.Anasterias antarctica (Lütken, 1857) is an oral-brooder species with a wide distributionthat plays an essential role as a top predator in the Beagle Channel intertidal and subtidal communities. Eight seasonal samplings (February, May, August, and November)were carried out during 2017 and 2018 at Ensenada Zaratiegui Bay (54°51´S;68°29´W). The main objective was to describe the reproductive cycle of A. antarctica ,the second to compare reproductive traits between two intertidal levels, and the third tostudy the ontogeny of the latest stages of the brooded offspring. Unexpectedly,females displayed two consecutive annual reproductive cycles. One cycle correspondsto the production of a few large oocytes (oocytes IV: 1080.0 ± 27.92 µm) that willdevelop into a lecithotrophic larva, which will be brooded (Cycle I), and the other cycleproduces many smaller oocytes (oocytes ii: 219.30 ± 12.59 µm) and co-occurs with thebrooding period (Cycle II). In both sexes, differences in the duration of gametogenesisand, in females also differential resource allocation patterns were observed betweenthe high and low intertidal zones. High intertidal individuals showed a delay in theonset of gametogenesis and an extension of its duration. Also, in females the leap inthe gonad wet weight (GW) occurs in latter reproductive stages in the high than in thelower intertidal individuals. Aborted eggs and abnormal metamorphic juveniles couldserve as nutritional reserves for the brooded offspring. Although the viability of thesecond spawning is still to be confirmed, this result raises new hypotheses about thereproduction of the brooder and wide-distributed A. antarctica.