Reproduction in urbanised coastal waters: shallow-water sea anemones maintain high genetic diversity and panmixia despite anthropogenic disturbances

Sea anemones are sedentary marine animals that tend to disperse via planktonic larvae and are predicted to have high population connectivity in undisturbed habitats. We test whether two sea anemone species can maintain high genetic connectivity despite living in two different tidal zones of a highly disturbed marine environment. More than 1000 loci with single-nucleotide polymorphisms (SNPs) loci were obtained with double-digest RADseq for 81 Stichodactyla haddoni and 99 Entacmaea quadricolor individuals to test for genetic panmixia. We find evidence of predominantly sexual reproduction and observed panmixia which indicates the absence of effective dispersal barriers despite living in a highly disturbed anthropogenic environment.