Advancing conservation breeding programs for marine invertebrates

In the face of ecosystem change and biodiversity loss caused by climate change and other stressors, conservation breeding, or captive breeding, with the aim of reintroduction for wild population recovery, is an emerging tool for preventing species' extinction and rehabilitating ecosystems. Most of these programs breed terrestrial megafauna, and few breed marine invertebrates. Marine invertebrates play diverse and pivotal roles in maintaining ecological integrity, and their conservation is vital for preserving healthy, functioning marine ecosystems. For sessile or mostly-sessile marine invertebrates, the likelihood of reproductive success scales with nearby population density. When population density declines, marine protected areas may be slow or ineffective in supporting recovery without human-assisted reproduction. However, most marine invertebrate breeding programs lack clear metrics that align with established conservation standards, and few have been directly linked to successful species recovery. Breeding these animals presents unique challenges related to their diverse life histories, demographics, and physiologies. At the same time, marine invertebrate programs offer both opportunities that are distinct from those of terrestrial programs and opportunities that are shared across all conservation breeding programs, regardless of the taxon. To advance the development of marine invertebrate conservation breeding and reintroduction metrics, this review assesses the challenges and opportunities for these programs across 10 focal areas, shedding light on needs and unresolved issues. We emphasize the current and potential future role of zoos and aquariums. As environmental change accelerates, conservation breeding will become increasingly vital to protecting biodiversity. Meeting this challenge requires strong, collaborative, and interdisciplinary programs that address the wide range of factors essential to the successful reintroduction and regeneration of marine ecosystems.