A glimmer of hope for an Endangered temperate soft coral: the first observations of reproductive strategies and early life cycle of Dendronephthya australis (Octocorallia: Malacalcyonacea)
Larkin, M.F.; Davis, T.R.; Harasti, D.; Smith, S.D.A.; Ainsworth, T.D.; Benkendorff, K. (2023). A glimmer of hope for an Endangered temperate soft coral: the first observations of reproductive strategies and early life cycle of Dendronephthya australis (Octocorallia: Malacalcyonacea). Mar. Biol. (Berl.) 170(11): 146. https://dx.doi.org/10.1007/s00227-023-04298-x
In: Marine Biology: International Journal on Life in Oceans and Coastal Waters. Springer: Heidelberg; Berlin. ISSN 0025-3162; e-ISSN 1432-1793, more
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| Keywords |
Dendronephthya australis Kükenthal, 1905 [WoRMS]
Marine/Coastal |
| Authors | | Top |
- Larkin, M.F.
- Davis, T.R.
- Harasti, D.
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- Smith, S.D.A.
- Ainsworth, T.D.
- Benkendorff, K.
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| Abstract |
The habitat-forming Endangered ‘cauliflower’ soft coral Dendronephthya australis, endemic to South-east Australia, is in rapid decline. To aid future conservation strategies, it is vital to understand the fundamental biological processes of this species, particularly reproduction. This study describes the first records of sexual reproduction and asexual clonal replication, with observations both in aquaria and in the wild. We used a combination of observations including histological analyses of fresh specimens, and images of colonies in situ taken over 19 years, to investigate the reproductive cycle of D. australis. Mature oocytes and spermaries were found to develop within colonies during February/March, 2022. We subsequently closed the life cycle of D. australis from colonies spawned in aquaria, documenting all stages of embryogenesis and larval development through to polyp metamorphosis, and successfully transplanted juvenile colonies back into the field and documented their growth over six months to a maximum 435 polyps in size. We also document autonomous fragmentation events to provide accounts of asexual clonal propagation. These records confirm that D. australis is gonochoric and likely a broadcast spawning species that is also capable of utilising asexual reproduction by clonal replication. Observations of mature gametes support the hypothesis that spawning activity coincides with the seasonal increase in water temperature, and is likely to be a continuous phenomenon over 5 months of the year (November–March). These observations not only contribute to the knowledge base for this species, but also provide invaluable information on reproductive strategies that will support conservation efforts to assist the recovery of D. australis populations. |
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