Mediterranean Marine Science Vol. 19, 2018 Spatio-temporal patterns based on demographic and genetic diversity of the purple sea urchin Paracentrotus lividus in the area around Corsica (Mediterranean Sea) DUCHAUD SOPHIE Université de Corse Pasquale Paoli, UMR CNRS 6134 Sciences Pour l’Environnement, 20250 Corte, France Université de Corse Pasquale Paoli, UMS CNRS 3514 Plateforme Marine Stella Mare, 20620 Biguglia DURIEUX ERIC Université de Corse Pasquale Paoli, UMR CNRS 6134 Sciences Pour l’Environnement, 20250 Corte Université de Corse Pasquale Paoli, UMS CNRS 3514 Plateforme Marine Stella Mare, 20620 Biguglia COUPE STEPHANE Univ Toulon, Aix Marseille Univ, CNRS/INSU, IRD, MIO UM 110, Mediterranean Institute of Oceanography, La Garde PASQUALINI VANINA Université de Corse Pasquale Paoli, UMR CNRS 6134 Sciences Pour l’Environnement, 20250 Corte Université de Corse Pasquale Paoli, UMS CNRS 3514 Plateforme Marine Stella Mare, 20620 Biguglia TERNENGO SONIA Univ Toulon, Aix Marseille Univ, CNRS/INSU, IRD, MIO UM 110, Mediterranean Institute of Oceanography, La Garde http://dx.doi.org/10.12681/mms.14184 Copyright © 2018 Mediterranean Marine Science http://epublishing.ekt.gr | e-Publisher: EKT | Downloaded at 03/10/2019 04:47:03 | To cite this article: DUCHAUD, S., DURIEUX, E., COUPE, S., PASQUALINI, V., & TERNENGO, S. (2018). Spatio-temporal patterns based on demographic and genetic diversity of the purple sea urchin Paracentrotus lividus in the area around Corsica (Mediterranean Sea). Mediterranean Marine Science, 19(3), 620-641. doi:http://dx.doi.org/10.12681/mms.14184 http://epublishing.ekt.gr | e-Publisher: EKT | Downloaded at 03/10/2019 04:47:03 | Research Article Mediterranean Marine Science Indexed in WoS (Web of Science, ISI Thomson) and SCOPUS The journal is available online at http://www.medit-mar-sc.net DOI: http://dx.doi.org/10.12681/mms.14184 Spatio-temporal patterns based on demographic and genetic diversity of the purple sea urchin Paracentrotus lividus in the area around Corsica (Mediterranean Sea) SOPHIE DUCHAUD1, 2, ERIC D. H. DURIEUX1, 2, STEPHANE COUPE3, VANINA PASQUALINI1, 2 and SONIA TERNENGO1, 2 1 Université de Corse Pasquale Paoli, UMR CNRS 6134 Sciences Pour l’Environnement, 20250 Corte, France 2 Université de Corse Pasquale Paoli, UMS CNRS 3514 Plateforme Marine Stella Mare, 20620 Biguglia, France 3 Université Toulon, Aix Marseille Univ, CNRS/INSU, IRD, MIO UM 110, Mediterranean Institute of Oceanography, La Garde, France Corresponding author: [email protected] Handling Editor: Xavier Turon Received: 12 July 2017; Accepted: 12 September 2018; Published on line: 14 December 2018 Abstract Sea urchins were harvested for decades in many areas throughout its distribution range, potentially leading to population collapse. In France, the purple sea urchin Paracentrotus lividus is intensively harvested. Yet, the demography and population dynamics remained under-documented, particularly in Corsica. In this context, we have characterized the fluctuations in density of several size classes at 8 sites around the island, and assessed the genetic diversity and structuring of the population. Densities recorded lie between 0 and 2.18 (± 0.41) individuals.m-2 and spatio-temporal variabilities have also been highlighted. The study of the influ- ence of vegetation cover on the size classes suggests that small- and medium- sized individuals prefer substrates of intermediate heights, whereas individuals with a diameter ≥ 5 cm are more often observed on encrusting substrates, and may be responsible for the continuation of this type of benthic community. The genetic study indicates a high genetic diversity with a low genetic struc- turing. The Ne values obtained are similar to those described in previous papers. Due to estimates of local contemporary Ne and the homogeneous genetic diversity, our data tend to show that the Corsican population of P. lividus is not overexploited. Keywords: Paracentrotus lividus; Abundances; Population dynamics; Vegetation cover; Substrates; Demographic history; Effective population size. Introduction sea urchin Arbacia lixula (Linnaeus, 1758) (Echinoidea: Arbaciidae) can affect the spatial repartition of P. lividus The purple sea urchin Paracentrotus lividus (La- (Chelazzi et al., 1997; Bulleri et al., 1999). Anthropic fac- marck, 1816) (Echinoidea: Parechinidae) is a species tors such as the destruction of habitats (Prado et al., 2012) commonly observed in coastal ecosystems and subtid- or harvesting (Andrew et al., 2002; Pais et al., 2007; Cec- al zones (Boudouresque & Verlaque, 2001), at shallow cherelli et al., 2011) can also impact population structure depths between 0 and 30 m (Mortensen, 1927) but with and especially size classes greater than 5 cm (minimum decreasing abundances after 10 m (Chelazzi et al., 1997). harvestable size). In particular, sea urchin fishing is com- In the Mediterranean Sea, it can be found on rocky reefs, mon in many Mediterranean countries as part of both in meadows of Zostera marina or in Posidonia ocean- professional and recreational practices (Guidetti, 2004), ica seagrass beds (Verlaque, 1987), where it can find a and the impact of overfishing onP. lividus has been high- suitable habitat and food resources (Prado et al., 2007). lighted (Andrew et al., 2002; Pais et al., 2012; Bertocci Sometimes sea urchins can be observed in coastal la- et al., 2014). Finally, global warming and the ensuing in- goons such as in Urbinu and Thau, where it lives on mud creasing water temperature could lead to the collapse of substrata or coarse sand (Fernandez et al., 2006, 2012). P. lividus populations (Yeruham et al., 2015; Rilov, 2016) The complexity and dependence of sea urchins in relation and promote the development of A. lixula (Privitera et al., to their habitat influence the population structure (Pra- 2011). As a result, in many areas, P. lividus populations do et al., 2012) and many factors like temperature and/ have been extensively surveyed over several successive or salinity can affect sea urchin abundances (Fernandez generations (see e.g. Hereu et al., 2012; Pais et al., 2012). et al., 2006). Presence of other species such as the black Sea urchins have a complex life cycle. During each Medit. Mar. Sci., 19/3, 2018, 620-641 620 http://epublishing.ekt.gr | e-Publisher: EKT | Downloaded at 03/10/2019 04:47:03 | reproductive season, P. lividus benthic adults produce of genetically diverse recruits. A similar pattern of genet- pelagic larvae, that can potentially disperse across long ic structure has been observed, overall, within the Med- distances from their place of birth (Cowen et al., 2006). iterranean basin, in the related sea urchin Arbacia lixula The new recruits that settle within a population, thus en- (Pérez-Portela et al., 2018). sure the demographic maintenance of the recipient pop- The measure of the effective population sizeN e, which ulations and influence its genetic diversity. As is the case is defined as the size of an ideal population that has the for most marine species with a pelagic developmental life same rate of change in allele frequencies or heterozy- stages, P. lividus presents high variability in both the level gosity, as the observed population, also gives an inter- of recruitment (Hereu et al., 2004) and the reproductive esting insight into the demographic history of a species. success (Hedgecock, 1994; Calderón et al., 2012), which Fluctuations of Ne estimates actually provide information may lead to a transient genetic structure within cohorts on variations of population sizes, across different time (Johnson & Black, 1982; Couvray & Coupé, 2018). frames (i.e. ancient to contemporary times) and spatial P. lividus populations are characterized by a high ge- scales (Wang, 2005). Thus, Ne estimates are interesting in- netic diversity within both Atlantic and Mediterranean dicators for the management and conservation of natural basins. Using either nuclear or mitochondrial markers, populations (Frankham, 2010; Hare et al., 2011; Ruggeri spatial structure has been evidenced between the Atlan- et al., 2016). Indeed, as the genetic diversity accounts for tic and the Mediterranean basins (Duran et al., 2004; the adaptive potential of a species, there are great con- Calderón et al., 2008), and between the Atlantic basin, cerns when consistent demographic decreases are ob- the Adriatic basin and the western and eastern Mediter- served. For instance, overharvesting has been shown to ranean basins (Maltagliati et al., 2010). More recently, substantially reduce the genetic diversity of numerous Paterno et al. (2017), using more than 1 000 single nu- marine species, and adversely affect their biology and cleotide polymorphisms (SNPs), revealed a differenti- natural sustainability. In the case of P. lividus, Calderón ation between the northern and southern regions of the et al. (2009a) have estimated the local Ne in a site of the Western Mediterranean basin. In addition, weak genetic Iberian coast at around three hundred individuals. structures, potentially below the larval dispersion range, In the end, although a growing number of works re- could be observed within basins and even within regions, ports that Ne can reliably estimate census Nc population these being explained by both the variability of reproduc- sizes (Ovenden et al., 2016), its use as a proxy of Nc tive success and putative, relatively stable, hydrological remains unsuitable for many marine species with high features (Penant et al., 2013; Couvray & Coupé, 2018). fecundity