Data for: From rivers to ocean basins: The role of ocean barriers and philopatry in the genetic structuring of a cosmopolitan coastal predator

The Bull Shark (Carcharhinus leucas) faces varying levels of exploitation
around the world due to its coastal distribution. Information regarding
population connectivity is crucial to evaluate its conservation status and
local fishing impacts. In this study, we sampled 922 putative Bull Sharks
from 19 locations in the first global assessment of population structure
of this cosmopolitan species. Using a recently developed DNA-capture
approach (DArTcap), samples were genotyped for 3,400 nuclear markers.
Additionally, full mitochondrial genomes of 384 Indo-Pacific samples were
sequenced. Reproductive isolation was found between and across ocean
basins (eastern Pacific, western Atlantic, eastern Atlantic, Indo-West
Pacific) with distinct island populations in Japan and Fiji. Bull Sharks
appear to maintain gene flow using shallow coastal waters as dispersal
corridors, whereas large oceanic distances and historical land-bridges act
as barriers. Females tend to return to the same area for reproduction,
making them more susceptible to local threats and an important focus for
management actions. Given these behaviours, the exploitation of Bull
Sharks from insular populations, such as Japan and Fiji, may instigate
local decline that cannot readily be replenished by immigration, which can
in turn affect ecosystem dynamics and functions. These data also supported
the development of a genetic panel to ascertain the population of origin,
which will be useful in monitoring the trade of fisheries products and
assessing population-level impacts of this harvest.