Hybridization and Speciation | Natural History Museum Stuttgart
Oceanographic barriers in an Octopus
Questions
Implications
Team
Background
Which oceanographic barriers affect genetic connectivity of coastal species?
Fisheries are essential for food security, and they preferential target coastal species causing their decline. Despite their importance, it is unclear if such coastal species are a single panmictic population, or if they are structured into different stocks by oceanographic barriers, limiting conservation measures for sustainable exploitation of these natural resources. To address these questions, we studied an octopus species (Octopus insularis) that lives in the tropical Atlantic Ocean and is targeted by coastal fisheries.
To understand how the evolution of this species is shaped by oceanographic barriers and environmental change over the last glacial cycle, we employed the first population genomic study on an Octopus species to answer:
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Which oceanographic barriers caused population divergence?
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Did island colonization cause changes in genetic diversity within populations?
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Did changes in habitat suitability cause changes in effective population size?
These results showed how depth and oceanic currents caused divergence of this recently described species into six distinct stocks, and showed that genetic diversity is highly asymmetric among stocks. Such findings can inform conservation measures and facilitate a sustainable exploitation of this species by fisheries.
Fig. 1. Sampling Octopus insularis. Our collaborator Françoise Lima collected fresh tissue samples during snorkeling, scuba diving, or purchasing octopus in local fish markets.
Fig. 2. Inbreeding follows island colonization. Using genomic markers we find that island populations show up to 4 times higher inbreeding than coastal populations. This is likely due both to a founder effect during colonization and to lower habitat availability in the islands.