The gametogenic cycle of an invasive semelparous heterobranch sea slug from northern Patagonia, Argentina, reveals an annual lifespan

BÖKENHANS, VERENA; PAREDES-MOLINA, FRANCISCO; CHAPARRO, OSCAR R; AVERBUJ, ANDRÉS

BULLETIN OF MARINE SCIENCE

ROSENSTIEL SCH MAR ATMOS SCI

Año: 2024

0007-4977

This study provides information about the reproductive cycle of the invasive side-gilled sea slug Pleurobranchaea maculata, currently widely distributed along the Argentine coast. The histological analysis of this simultaneous hermaphrodite showed characteristics of a semelparous species with an annual life cycle. The highest spermatogenic and oogenic activity was observed from August to January. Partial evacuations of mature oocytes, measuring over 100 μm in average diameter, occurred continuously during the long spawning season. Oviposition events started in winter and increased in frequency with increasing photoperiod (hours of light) until summer solstices. During February and March, post-reproductive and immature individuals coexisted, while mature individuals were rarely observed. These results represent important information on the reproductive patterns of an invasive species of worldwide ecological and sanitary concern.