Abstract
Patterns of connectivity and self-recruitment are recognized as key factors shaping the dynamics of marine populations. Connectivity is also essential for maintaining and restoring natural ecological processes with genetic diversity contributing to the adaptation and persistence of any species in the face of global disturbances. Estimates of connectivity are crucial to inform the design of both marine protected areas (MPAs) and MPA networks. Among several approaches, genetic structure is frequently used as a proxy for patterns of connectivity. Using 8 microsatellite loci, we investigated genetic structure of the two-banded sea bream Diplodus vulgaris, a coastal fish that is both commercially and ecologically important. Adults were sampled in 7 locations (stretches of coastline approximately 8 km long) and juveniles in 14 sites (~100 to 200 m of coastline) along 200 km of the Apulian Adriatic coast (SW Adriatic Sea), within and outside an MPA (Torre Guaceto MPA, Italy). Our study found similar genetic diversity indices for both the MPA and the surrounding fished areas. An overall lack of genetic structure among samples suggests high gene flow (i.e. connectivity) across a scale of at least 200 km. However, some local genetic divergences found in two locations demonstrate some heterogeneity in processes renewing the population along the Apulian Adriatic coast. Furthermore, two sites appeared genetically divergent, reinforcing our observations within the genetic makeup of adults and confirming heterogeneity in early stage genetics that can come from either different supply populations or from chaotic genetic patchiness occurring under temporal variation in recruitment and in the reproductive success. While the specific role of the MPA is not entirely known in this case, these results confirm the presence of regional processes and the key role of connectivity in maintaining the local population supply.
Highlights
Levels of self-recruitment within and connectivity among populations are key factors influencing marine population persistence and stock sustainability [1], as well as the efficiency of PLOS ONE | DOI:10.1371/journal.pone.0167441 December 1, 2016
We demonstrate that 12% of juveniles sampled in TGMPA are originated from adults in the surrounding fished areas, while 3% of juveniles sampled outside TGMPA are originated inside
This study showed that TGMPA is part of an interconnected system and that the high gene flow among Diplodus vulgaris populations is maintaining the local population supply
Summary
To assess the observed genetic differentiation at a local scale, 7 locations (i.e. stretches of coastline approximately 8 km long) were selected starting from TGMPA, spanning both northward and southward, up to about 100 km from the MPA borders (Fig 1). 525 adults from 7 locations were sampled from April 2010 to July 2011 (S1 Table). In conjunction with the adult sampling efforts, a total of 755 juveniles (S2 Table) were sampled in May 2010 at the same 7 locations where the adults were sampled but duplicating sampling in each location (i.e. randomly selecting two sites within each location; Fig 1) to account for potential local variability. For fishing at the two sites located within the TGMPA, the MPA management body provided a specific authorization (number 0003583-PM-11). The sampling activity did not involve endangered or protected species. Fin clip of adults was preserved in 95% ethanol for further DNA extraction
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
