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Vol. 50 No. 4, 2011
Oocyte Production, Fecundity, and Size at the Onset of
Reproduction of Tripalea clavaria (Cnidaria: Octocorallia:
Anthothelidae) in the Southwestern Atlantic
Adriana
C. Excoffon1, María L. Navella1, Fabián H. Acuña1,2,*, and Agustín
Garese1,2
1Departamento
de Ciencias Marinas, Facultad de Ciencias Exactas y Naturales, Univ.
Nacional de Mar del Plata, Funes 3250, Mar del Plata 7600, Argentina
2National Council for Scientific and Technical
Research of Argentina (CONICET), Rivadavia 1917, Buenos Aires, Argentina
Adriana
C. Excoffon, María L. Navella, Fabián H. Acuña, and Agustín
Garese (2011) The octocoral Tripalea clavaria is a
gonochoristic species distributed in the southwestern Atlantic from Rio
de Janeiro to the Magellan Strait and is restricted to waters with
temperatures of < 20°C. Female colonies are significantly more
abundant than males, and their gonads are present throughout the entire
year. Male fertile colonies were found only in Dec.-June, because the
spermatogenic cycle is shorter than oogenesis, as is characteristic of
other octocorals. Fertilization is probably internal, taking place
within polyps of female colonies in Mar.-May. Planulae of T. clavaria
were found in Apr.- June. The length of larvae was 554-1980 µm, and a
maximum of 4 planulae was observed per polyp. The high number of large
oocytes per polyp implies that this species allocates most of it
energetic resources to sexual reproduction. Regarding the variability
of volume of oocytes per polyp, the lowest value was 1.35 × 10-5 mm3,
and the highest was 0.17 mm3. Although the reproductive features of T.
clavaria are similar to those of other gorgonian octocorals, it has
some exceptional features. Despite having small and unbranched
colonies, this species exhibits a small colony size at 1st reproduction
(2.7 cm) and is highly fecund, producing high numbers of large oocytes
compared to other octocorals. Such reproductive traits could explain
its successful recruitment on the limited available substrate of rocky
outcrops, often characterized by strong currents and turbulence.
Key words: Octocoral,
Tripalea clavaria, Sexual reproduction, Southwestern Atlantic.
*Correspondence: Tel: 54-223-4753554. Fax: 54-223-4753150.
E-mail:facuna@mdp.edu.ar
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