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Summary
Very little is currently known of the reproductive biology of many deep-sea stony corals. This is an important knowledge gap that requires attention as without information on how these corals reproduce, such as reproductive mode, fecundity, and larval behaviour, we cannot understand their reproductive or dispersal potential which is linked to their ability to recovery following disturbance. Knowledge of reproductive biology is, therefore, needed to inform risk assessments and management plans for these protected species.
In January/February 2025 the RV Sonne, a German research vessel, undertook an expedition titled “Cold-Water Coral Biology and Geology off Aotearoa New Zealand” (CoralNewZ). This provided the opportunity to collect live, protected, deep-sea coral specimens from the New Zealand region via targeted sampling with a deep-sea capable Remote Operated Vehicle (ROV) and video-guided box corer.
A total of 24 live coral specimens were collected during the voyage: six from Fiordland (three Madrepora oculata, two Madrepora cf oculata and one Antipathella fiordensis); and 18 from the Chatham Rise area (eight Solenosmilia variabilis, three Enallopsammia rostrata, two Madrepora oculata and five Goniocorella dumosa). The corals were held in an onboard aquarium system before being transferred to NIWA Wellington’s Marine Environmental Manipulation Facility (MEMF) on return to port in Wellington.
To date, the M. oculata from Fiordland and the S. variabilis and G. dumosa from the Chatham Rise appear to be mostly healthy with regular sightings of extended tentacles. Specimens of remaining species all appear unhealthy and are considered unlikely to survive long-term.
The aim of this project is to maintain healthy and reproductive populations of not previously studied species of stony coral in an aquarium environment for a calendar year (i.e. between Feb 2025 and Feb 2026) and to use them to improve our knowledge of their reproductive and larval biology. We will use histological approaches to determine reproductive traits and corals held in the aquarium will undergo periodic histological sampling.
This first-year progress report is a summary of specimen collection, observations to date, and next steps following establishment of the corals in MEMF post-voyage.
Publication information
Beaumont, J., Marriott, P., Freiwald, A., Beuck, L. 2025. Assessing reproductive capacity to infer productivity, vulnerability, and resilience of protected deep-sea corals in the New Zealand region. Progress report prepared for CSP project POP2024-02 by NIWA for the Department of Conservation. 31 p.