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BCBC2020-01: Protected coral reproduction (PDF, 8,801 K)

Summary

This study summarises recent knowledge of reproduction for protected deep-sea and cold-water corals in New Zealand and for related species for which reproductive studies have been carried out globally. While there have been some recent advances in knowledge in this field, and the research described in our literature review has highlighted new observations of spawning behaviours, reproductive modes and fecundity estimates for key deep-sea coral groups, there remains large knowledge gaps for many species globally. An improved understanding of all aspects of coral reproduction is critical for supporting a long-term plan to manage and conserve populations of protected corals for the New Zealand region.

In this project, the literature review showed that there is variability in spawning frequency, that species that show continuous spawning or gametogenesis may still be influenced by environmental cues, and a range of reproductive modes occur among even closely related corals. Information compiled from an interrogation of the NIWA Invertebrate Collection (NIC) database niwainvert has enabled the production of a prioritised list of suitable samples for a detailed New Zealand reproductive study, based primarily on histology, several of which were identified as medium and/or high-risk groups in a 2014 semi-quantitative pilot ecological risk assessment.

The preliminary results of a recent opportunistically observed spawning event by G. dumosa in NIWA’s Marine Environmental Manipulation Facility (MEMF), are also summarised. This was the first observation of live spawning by a deep-sea coral in New Zealand, and as such represents a major milestone in the field of deep-sea coral reproduction, changing our understanding of the reproductive mode and seasonality of spawning for this species. Detailed reproductive descriptions based on the examination of a sample of histology slides for adult G. dumosa sampled in September 2020 are presented.

Finally, recommendations are made for further research that may improve our understanding of reproductive strategies for several coral groups, with the aim of providing improved information on population characteristics and susceptibility to the effects of fishing for protected species populations, as outlined in the CSP Protected Coral Medium Term Research Plan. Future research is needed to describe and quantify the baseline reproductive biology and output at both the colony and population level for the selected New Zealand protected corals.

Publication information

Tracey, D. et al (2021). Protected coral reproduction. Literature review recommended study species, and description of spawning event for Goniocorella dumosa.  BCBC2020-01 final report prepared by NIWA for the Conservation Services Programme, Department of Conservation. 63 p.