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Lic. Verena D. Bökenhans

Doctoral Fellow CONICET

Lic. Verena Bökenhans

bokenhans@cenpat-conicet.gob.ar

My research

My doctoral research is focused on the reproductive biology and trophic ecology of Pleurobranchaea maculata, an invasive opistobranch present al Golfo Nuevo, Patagonia, Argentina. This work will contribute to the understanding of the reproductive modality (related to the invasive potential of the species) and its interaction with the native ecosystem. I have previously worked on the nassarrid gastropod Buccinanops globulosus endemic to the Southwestern Atlantic Ocean. The species is of growing commercial importance for local consumption, and is being exported to international markets. Therefore its age and individual growth are required for evaluation and future successful management of this valuable resource. Age and growth of two populations of B. globulosus were studied in Golfo Nuevo, Patagonia, Argentina. Two age estimation techniques were compared, using operculum growth rings and shell marks (previously validated by Stable Isotopes Analysis of oxygen).

Research goals
  • Study the mating behavior and reproductive mechanisms of Pleurobranchaea sp., as well as to determine the reproductive maturity size.
  • Relate the reproductive cycle with environmental variables.
  • Describe the egg masses and intracapsular embryonic and larval development.
  • Conduct aquarium experiments in order to induce spawning by varying temperature and photoperiod (hours of light:dark).
  • Describe the diet of Pleurobranchaea sp. by means of in situ observations and estimate its trophic position using stable isotopes analysis (δ13C y δ15N).
Research topics

The invasive opistobranch Pleurobranchaea maculata which is currently spreadin along the Argentina coast, is native from New Zeland. Although the species has been largely studied for presenting TTX, a potent neurotoxin, little information on its reproductive biology and trophic ecology in its new habitat is found.

Understanding its reproductive biology and trophic ecology may help explaining its rapid expansion along the Argentinian cost, providing scientific knowledge that may help on the development of management policies.

Reproductive studies of Pleurobranchaea maculata, in particular the gametogenic cycle and its seasonality, mating behaviour and reproductive maturity are being carried out by means of direct field observation, aquarium experiences, classical histology and optical and scanning electron microscopy (SEM) techniques. Gonadal cell apoptosis along the gametogenic cycle is detected by performing a terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelling (TUNEL) assay. The morphology, structure and organization of the egg masses, spawning period and intracapsular development is described through field observations, optical microscopy and aquarium experiences. Dietary studies are studied by in situ observations and stable isotopes analysis of δ13C and δ15N in order to define the trophic relationships of this species and its possible prey.

 

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