Title : Enhancing sustainable aquaculture: Genetic insights into local adaptation and broodstock selection using the Cape sea urchin, parechinus angulosus
Abstract:
As the world’s population continues to grow, there is an increasing demand to identify sustainable food sources and progress ethical aquaculture practices. Echinoculture represents a time-honored and effective means of ensuring food security, additionally offering economic benefits. Genetic studies on sea urchins offer valuable insights for aquaculture, enhancing breeding practices by enabling the selection of desirable traits, and identifying genetic factors that influence early-stage survival, supporting the identification of robust lineages, ultimately fostering stronger, more viable populations in captivity. Using genetic methods, this study aimed to develop a protocol for determining the best wild populations from which to collect broodstock. To achieve this, I examined the genomic variation, local adaptation, and phylogeographic patterns of the Cape sea urchin (Parechinus angulosus) across its South African distribution range, highlighting mechanisms of population resilience. Genome-wide analyses revealed significant population differentiation, with measures exceeding averages for marine species, identifying loci potentially undergoing adaptive divergence. These outlier loci suggest that selective pressures have led to local adaptations, supported by findings in comparable marine species. Given the absence of a dedicated reference genome, functional insights of outlier single nucleotide polymorphisms were derived from homologous annotated genes in a closely related sea urchin species, revealing loci involved in transcription and mitochondrial processes. Genetic diversity varied substantially between the east and west coasts of South Africa, implying that populations with higher diversity may exhibit greater adaptive potential under changing conditions. This research supports the growing evidence that marine populations can maintain local adaptation despite gene flow, challenging assumptions of homogeneity within marine species with high dispersal potential. Populations with unique adaptive traits are crucial not only for conservation but also for optimising aquaculture practices, enabling the development of resilient broodstock that can support sustainable echinoculture under diverse environmental conditions.
