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Every summer, corals across Florida’s Coral Reef do something extraordinary.  On just a handful of nights, synchronized by the phases of the moon and other environmental cues that scientists are still working to fully understand, entire colonies release bundles of eggs and sperm into the water. For restoration scientists, coral spawning is a window into one of the most important, and least understood, parts of the coral life cycle.  Once again, CRF teams and partner organizations were there to watch it unfold, spending a week at the bleeding edge of research into coral sexual reproduction.   From July 31 through August 10, CRF scientists joined collaborators aboard Shedd Aquarium’s R/V Coral Reef II, working first at our Tavernier Coral Nursery and later at Horseshoe Reef. Alongside teams from Shedd Aquarium, the Southeast Zoo Alliance for Reproduction and Conservation (SEZARC), the University of Miami, and the University of Hawaii, we collected gametes, produced coral larvae, cryopreserved genetic material, and ran experiments designed to answer a deceptively simple question: what does it take for a baby coral to successfully become part of a reef?  A quiet year for Acropora At our Tavernier nursery, scientists observed all three Caribbean Acropora species spawning: staghorn coral (Acropora cervicornis), elkhorn coral (A. palmata), and the hybrid fused staghorn (A. prolifera).  But compared with 2025, it was a quiet year.  We weren't alone. Colleagues at other Florida restoration and research organizations reported a similarly difficult year, with poor gamete quality and crashes of cultures after fertilization.  Elkhorn spawning was particularly weak, leaving scientists with relatively few viable gametes to work with. The team successfully produced developed staghorn coral (A. cervicornis) larvae from crosses between staghorn colonies. Experimental crosses between staghorn and elkhorn (A. cervicornis × A. palmata), and between elkhorn and fused staghorn (A. palmata × A. prolifera), showed some initial signs of fertilization, but those cultures did not survive beyond roughly 36 hours.  Spawning success naturally varies from year to year, and strong years rarely arrive back-to-back. But research that we support every spawning season is providing increasingly important insights, particularly as Florida's remaining Acropora populations face increasingly challenging conditions.  SEZARC scientists were also aboard to cryopreserve sperm, adding new A. cervicornis genotypes to existing genetic banks and preserving material from CRF's A. prolifera. These frozen genetic repositories help safeguard genetic diversity and preserve options for future research and restoration.  Then came the boulder corals  If Acropora spawning was subdued, the massive reef-building corals had other plans.  On August 5 at Horseshoe Reef, the team observed spawning by two species of Orbicella — mountainous star coral (O. faveolata) and lobed star coral (O. annularis) — as well as symmetrical brain coral (Pseudodiploria strigosa).  From approximately 12 O. faveolata colonies alone, the team collected around 550 milliliters of gametes, ultimately producing more than one million larvae.  It was a dramatic change from 2025, when the team collected from the same colonies at Horseshoe Reef but saw nowhere near this amount of spawn.  CRF teams conducting separate observations at Cheeca Rocks also witnessed wild O. faveolata spawning on August 6 and 7.  And then the real work began.  What happens after spawning?  Producing larvae is only the beginning. For restoration, one of the biggest questions is what happens next.  This year, CRF and the Shedd Aquarium deployed approximately 25,000 staghorn coral larvae and 180,000 mountainous star coral larvae across five different types of settlement substrates.  The experiment will compare different substrate materials, as well as substrates conditioned offshore in CRF's nursery with those conditioned on land at Keys Marine Laboratory. Beginning in approximately three months, scientists will examine which surfaces attracted the most coral settlers, and, critically, how many of those tiny coral spats become juveniles.  Last year's experiments show just how difficult that can be.  One staghorn recruit from CRF's 2025 spawning work remains alive today. Five others survived initially but have since disappeared. Interestingly, a wild mustard hill coral (Porites astreoides) that naturally settled at roughly the same time on a neighboring substrate has grown rapidly, while the surviving staghorn remains tiny. But why?  That's precisely the kind of question these experiments are designed to investigate. Fast-growing adult Acropora may spend their earliest months growing relatively slowly, potentially leaving new recruits vulnerable to competition from algae or grazing by fish.  For CRF, understanding these missing stages of the coral life cycle matters enormously. Restoration isn't only about producing more corals. It's about understanding what allows corals to reproduce, settle, survive, and eventually become the next generation of reef builders.  This year's spawning season gave us hundreds of thousands of new opportunities to find out.