Papers by Giacomo Bernardi
Aim To understand why and when areas of endemism (provinces) of the tropical Atlantic Ocean were ... more Aim To understand why and when areas of endemism (provinces) of the tropical Atlantic Ocean were formed, how they relate to each other, and what processes have contributed to faunal enrichment.
Reef fishes exhibit a bipartite life cycle where a benthic adult stage is preceded by a pelagic d... more Reef fishes exhibit a bipartite life cycle where a benthic adult stage is preceded by a pelagic dispersal phase during which larvae are presumed to be mixed and transported by oceanic currents. Genetic analyses based on twelve microsatellite loci of 181 three-spot dascyllus (Dascyllus trimaculatus) that settled concurrently on a small reef in French Polynesia revealed 11 groups of siblings (1 full sibs and 10 half-sibs). This is the first evidence that fish siblings can journey together throughout their entire planktonic dispersal phase (nearly a month long for three-spot dascyllus). Our findings have critical implications for the dynamics and genetic structure of fish populations, as well as for the design of marine protected areas and management of fisheries.
Conservation Genetics, 2007
Following aquarium releases, invasive lionfishes have colonized large areas of the Caribbean and ... more Following aquarium releases, invasive lionfishes have colonized large areas of the Caribbean and western Atlantic, resulting in an immense ecological damage. The early stages of that invasion are poorly known. Indeed, a lag of time between the introduction and detection often preclude genetic characterization of that crucial phase. With elevated awareness, the recent invasion of Pterois miles was quickly detected in the Mediterranean Sea. We hereby show that the very first individuals establishing populations in the Mediterranean Sea display haplotypes that nest within the large genetic diversity of Red Sea individuals, thus indicating an invasion via the Suez Canal. We also show that only two haplotypes are detected in the Mediterranean Sea, suggesting that few individuals may have been involved in the invasion. Thus, we conclude that the Mediterranean invasion is the result of a movement of individuals from the Red Sea, rather than from other means, and that low genetic diversity does not seem to have a negative effect on the success and spread of lionfish into the Mediterranean Sea. Invasions of non-indigenous species (NIS) are widely regarded as a major threat to native ecosystems and to global biodiversity 1, 2. The Atlantic invasion of two lionfish species (Pterois volitans, P. miles) since the 1990s has been outstanding. Lionfishes have rapidly spread throughout the Western North-Atlantic, the Caribbean Sea and the Gulf of Mexico, reaching very high densities and inflicting important loss of ecological services 3–5. The native range of the red lionfish, P. volitans is the tropical Pacific Ocean, while the congeneric common lionfish, P. miles is restricted to the tropical Indian Ocean and the Red Sea 3 , with a narrow overlap in the Indonesian region. The presence of the lionfish in the Atlantic is likely due to human-mediated introduction through the ornamental fish trade 6 and it is acknowledged that a small founder population originated from aquaria in south Florida 7, 8. The invasion of the western Atlantic has been disastrous as the invaders directly compete for food resources with native predators and intensively feed on native reef-fishes 4, 9–13. Pterois miles appeared in the eastern Mediterranean Sea in 2012 and has relatively quickly proliferated and spread, reaching the central Mediterranean Sea 14–20. A single specimen was recorded 21 years earlier in the eastern Mediterranean Sea 21 but no other individuals were observed afterwards. Given its conspicuous morphology and significant human presence in the eastern Mediterranean Sea, it is most probable that the recent sightings correspond to a new invasive event 14. Considering the situation in the western Atlantic, it remains unclear whether the occurrence of the invading population in the Mediterranean Sea is a result of aquarium release, transport by ship ballast water, dispersal event from an Atlantic source or passage through the Suez Canal as Lessepsian immigrant, a major source of NIS introductions in the eastern Mediterranean Sea 22–25. The aim of this work is to give insights on the origin and genetic diversity of the early stage of invasion of the non-indigenous lionfish P. miles recently established in the Mediterranean Sea. Mitochondrial DNA sequences from the donor (Red Sea) and the recipient regions (Mediterranean Sea)were used to investigate the genetic divergence between regions and possible bottleneck effects. In addition, DNA data from GenBank were used to supplement our data and relate as a control, to its congeneric, P. volitans. The current findings are discussed in the light of non-indigenous fish species early invasion stages.
Scientific Papers by Giacomo Bernardi
Population disjunctions, as a first step toward complete allopatry, present an interesting situat... more Population disjunctions, as a first step toward complete allopatry, present an interesting situation to study incipient speciation. The geological formation of the Baja California Peninsula currently divides 19 species of fish into disjunct populations that are found on its Pacific Coast and in the northern part of the Gulf of California (also called the Sea of Cortez), but are absent from the Cape (Cabo San Lucas) region. We studied the genetic makeup of disjunct populations for 12 of these 19 fish species. Phylogeographic patterns for the 12 species can be separated into two major classes: a first group (eight species) showed reciprocal monophyly and high genetic divergence between disjunct populations. A second group (four species) displayed what appeared to be panmictic populations. Population structure between Pacific Coast populations, across the Punta Eugenia biogeographic boundary, was also evaluated. While dispersal potential (inferred by pelagic larval duration) was a poor predictor of population structure between Gulf of California and Pacific populations, we found that population genetic subdivision along the Pacific Coast at Punta Eugenia was always positively correlated with differentiation between Pacific and Gulf of California populations. Vicariant events, ongoing gene flow, and ecological characteristics played essential roles in shaping the population structures observed in this study.
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Papers by Giacomo Bernardi
Scientific Papers by Giacomo Bernardi