A comparison of in situ and on-vessel larval rearing for coral seeding

Coral sexual recruitment is critical to reef recovery yet often fails on degraded reefs. Coral seeding is one approach to artificially increase the densities of coral settlers on reefs and can be applied in many ways. A thorough comparison of seeding-method performance is needed to inform restoration decisions yet is difficult to undertake given the cost and complexities around employing multiple methods simultaneously. Here, we first designed a vessel-based coral-spawning aquaculture system. Then we undertook an experimental comparison of the performance of larvae reared in the on-vessel system with those reared in in situ rearing pools (SECORE coral rearing in situ basins [CRIBs]). We parameterized survival estimates and assessed post-deployment survival of spat generated using each method. We also quantified survival of spat reared in situ and deployed across six sites on an inshore reef system of the Great Barrier Reef. Larval survival was lower when rearing in situ than on the vessel (3.8 vs. 66.1%, respectively), but settlement behavior and post-settlement survival were comparable between rearing treatments, with yield averaging 66 and 72% after 3 months of deployment, from CRIBs and culture tanks, respectively. Spat survival was also comparable across treatments, averaging 5 ± 8%. On-vessel rearing was more costly but supported higher survival, increased portability, and enabled more control and manipulation of rearing conditions. By contrast, in situ methods were low-cost, deployable from shore, and low-maintenance. Armed with this information, managers and practitioners can determine the most appropriate method(s) for a given restoration project.The data within this record support the publication.

珊瑚有性繁殖幼体补充对珊瑚礁恢复至关重要，但在退化珊瑚礁上这一过程往往难以实现。珊瑚播种是一种可通过多种方式人工提升珊瑚礁上珊瑚定居幼体密度的修复手段，但目前亟需开展该类方法性能的全面对比研究以指导修复决策，然而由于同时实施多种方法的成本与复杂性限制，此类研究往往难以开展。本研究首先设计了一套船载珊瑚产卵养殖系统，随后对船载系统培育的幼虫与原位（in situ）培育池（SECORE珊瑚原位培育池[CRIBs]）培育的幼虫的性能开展了实验对比。我们对两种方法培育的珊瑚稚体的存活率估算参数进行了标定，并评估了其投放后的存活率；此外，我们还对原位培育并投放至大堡礁（Great Barrier Reef）近岸礁系统6个点位的珊瑚稚体的存活率进行了量化。结果显示，原位培育的幼虫存活率显著低于船载培育（分别为3.8%与66.1%），但两种培育方式下的幼虫附着行为与附着后存活率无显著差异；CRIBs与养殖箱培育的稚体在投放3个月后的平均定植成功率分别为66%与72%。不同处理组的稚体存活率亦无显著差异，平均存活率为5%±8%。船载培育虽成本更高，但可实现更高的幼虫存活率、更强的便携性，且能更好地调控培育条件与开展操作；与之相对，原位培育方法成本低廉、可从海岸直接部署且维护需求极低。依托本研究所得结果，珊瑚礁修复管理者与实践者可针对具体修复项目选择最适配的方法。本数据集收录的数据可为该研究成果的发表提供支撑。