Millions of eggs on volcanic summits reveal extraordinary deep-sea reproductive strategies

We studied two newly discovered nurseries on seamounts to examine the reproductive investment of large, solitary deep-sea predators. In situ observations revealed millions of skate egg cases on each summit—orders of magnitude beyond anything previously known—and deep-sea reproductive behaviours, including egg-laying females actively selecting habitats across nested spatial scales: from the seamounts, to their highest ridges, and ultimately to sites of localized geothermal venting. Our findings show deep-sea life histories operating across extensive landscapes and timelines–including potentially decade-long incubation–yet with substantial reproductive investment ultimately concentrated within small, specific geological habitats.