Metabarcoding approach for nonindigenous species surveillance in marine coastal waters

Highlights: • Metabarcoding was applied for the surveillance of plankton communities and NIS detection. • The results were compared to those from the conventional monitoring. • Four of five detected NIS were identified exclusively by metabarcoding. • Most of the detected NIS were benthic organisms with planktonic larval stage. • The reported taxonomic composition was consistent between two methods at a family level. Abstract: In this study, high-throughput sequencing (HTS) metabarcoding was applied for the surveillance of plankton communities within the southeastern (SE) Baltic Sea coastal zone. These results were compared with those from routine monitoring survey and morphological analyses. Four of five nonindigenous species found in the samples were identified exclusively by metabarcoding. All of them are considered as invasive in the Baltic Sea with reported impact on the ecosystem and biodiversity. This study indicates that, despite some current limitations, HTS metabarcoding can provide information on the presence of exotic species and advantageously complement conventional approaches, only requiring the same monitoring effort as before. Even in the currently immature status of HTS, this combination of HTS metabarcoding and observational records is recommended in the early detection of marine pests and delivery of the environmental status metrics of nonindigenous species

Rate of biological invasions is lower in coastal marine protected areas

Marine biological invasions threaten biodiversity worldwide. Here we explore how Marine Protected areas, by reducing human use of the coast, confer resilience against the introduction of non-indigenous species (NIS), using two very different Pacific islands as case studies for developing and testing mathematical models. We quantified NIS vectors and promoters on Vancouver (Canada) and Moorea (French Polynesia) islands, sampled and barcoded NIS, and tested models at different spatial scales with different types of interaction among vectors and between marine protection and NIS frequency. In our results NIS were negatively correlated with the dimension of the protected areas and the intensity of the protection. Small to medium geographical scale protection seemed to be efficient against NIS introductions. The likely benefit of MPAs was by exclusion of aquaculture, principally in Canada. These results emphasize the importance of marine protected areas for biodiversity conservation, and suggest that small or medium protected zones would confer efficient protection against NIS introduction

Microplastics pollution in genetically connected populations of Holothuria forskali from south Bay of Biscay

IntroductioSea cucumbers are increasingly demanded as seafood in different cultures around the world. Holothurians could be potentially exploited in southern Bay of Biscay (Iberian Cantabrian coast) where they are not fished yet. Recent studies show relatively high pollution by emerging pollutants like microplastics (MPs) in the region; perhaps the exposure of holothurians to those MPs may put them at risk.Material and methodsHere we analysed 60 samples of Holothuria forskali taken from the west and east of the Cape Peñas transition zone in different seasons. MPs were quantified from body wall tissue, and mitochondrial DNA sequences (16S and COI genes) were employed to determine population connectivity and infer replenishment capacity.ResultsMuch higher MPs content in holothurian tissue than in water and sediments confirmed bioconcentration in this species. Significant differences between sampling locations were found, holothurian pollution being consistent with the occurrence of MPs sources like rivers, fishing ports and aquaculture. Genetic connectivity and no signals of diversity reduction in the most polluted samples suggest population replenishment capacity in H. forskali in the studied region. Results for a few samples of H. mammata from the same sampling points confirmed a higher MPs pollution at the west of Cape Peñas.DiscussionAccording to these exploratory results, sea cucumbers seem to accumulate MPs especially in the western Cantabrian Sea. Further studies are recommended to understand the possible MPs threat for these holothurian species

Outreach channels for polar science: an expedition to Kerguelen Islands as a case study

Polar science outreach is strongly needed, because besides promoting the utility of polar studies for society as a whole, it can generate public demand for new projects and expeditions. The dissemination of polar discoveries should be reinforced in countries without polar territories and for which polar science might not be a priority. In this pilot study (N =182 participants) we have contrasted the opinions of polar scientists (French, Belgian, British, Canadian, Australian, German, Italian and Spanish researchers) with those of a potentially interested public (graduate students of pedagogy and biology), in order to assess if the communication channels employed by polar researchers to make their results public align with those used by non-polar experts for learning about polar discoveries. The results revealed that scientific publications and presentations were considered a priority by the researchers, and these scientific communication channels were preferentially employed. Only a minority of researchers thought that non-scientific publications might be a good communication resource. In contrast, both groups of students, which considered polar research important but not a top priority, employed the Internet as their main channel for information about polar discoveries. Students assessed the use of polar discoveries as positive for educational purposes at both Primary and Secondary levels. The information presently received by students was perceived as being too generalist and the main suggestions to improve outreach in this field, in addition to the use of Internet, were more rapid dissemination of new discoveries

Mislabelling in megrims: implications for conservation

Mislabelling of fish catch and commercial seafood products is relatively frequent worldwide and can affect fisheries management exploitation when stock estimates are based on landings. In this study we have analyzed genetically 239 commercial lots of two morphologically similar species of megrims (genus Lepidorhombus) that are caught together in mixed fisheries. A high proportion of mislabelling was detected, suggesting enormous underreported exploitation of one of the species, which can be endangered if the problem persists. These results highlight the urgency of applying currently available species-specific molecular tools in fisheries sciences for preventing biodiversity losses in exploited species

Interspecific hybridization in pilot whales and asymmetric genetic introgression in northern Globicephala melas under the scenario of global warming

© The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS One 11 (2016): e0160080, doi: 10.1371/journal.pone.0160080 .Pilot whales are two cetacean species (Globicephala melas and G. macrorhynchus) whose distributions are correlated with water temperature and partially overlap in some areas like the North Atlantic Ocean. In the context of global warming, distribution range shifts are expected to occur in species affected by temperature. Consequently, a northward displacement of the tropical pilot whale G. macrorynchus is expected, eventually leading to increased secondary contact areas and opportunities for interspecific hybridization. Here, we describe genetic evidences of recurrent hybridization between pilot whales in northeast Atlantic Ocean. Based on mitochondrial DNA sequences and microsatellite loci, asymmetric introgression of G. macrorhynchus genes into G. melas was observed. For the latter species, a significant correlation was found between historical population growth rate estimates and paleotemperature oscillations. Introgressive hybridization, current temperature increases and lower genetic variation in G. melas suggest that this species could be at risk in its northern range. Under increasing environmental and human-mediated stressors in the North Atlantic Ocean, it seems recommendable to develop a conservation program for G. melas.LM had a PCTI Grant from the Asturias Regional Government, referenced BP 10-004. MAS was supported by a 2013 FCT Investigator contract through POPH, QREN European Social Fund and the Portuguese Ministry for Science and Education. This study was also supported by a grant from the Principality of Asturias (reference: GRUPIN-2014-093)

Novel tools for early detection of a global aquatic invasive, the zebra mussel Dreissena polymorpha

1. This study presents a species-specific DNA-based marker for detection of the zebra mussel Dreissena polymorpha, recognized as one of the worst invasive species worldwide. 2. The marker was developed in silico and experimentally tested on environmental samples. Gel and capillary electrophoreses for visualization of the PCR products were compared. 3. Marker specificity and sensitivity were assessed in vitro by cross-amplifications and serial dilutions, respectively. The method allows detecting at least 0.7 ng of Dreissena DNA per μL and cross-species amplification was not found in any case. 4. Next-generation sequencing (NGS) metabarcoding (PCR amplification and massive sequencing of a DNA barcode) was used as an independent method for verifying presence of Dreissena DNA molecules in environmental plankton samples collected from the south-eastern Baltic Sea. 5. The consistency between NGS results reporting presence of Dreissena and positive PCR amplification of the marker from the plankton samples confirmed the efficacy of this highly reproducible, fast, cheap and technically easy method

eDNA and specific primers for early detection of invasive species – A case study on the bivalve Rangia cuneata, currently spreading in Europe

Intense human activities facilitate the successful spread and establishment of non-indigenous aquatic organisms in marine and freshwater ecosystems. In some cases such intrusions result in noticeable and adverse changes in the recipient environments. In the Baltic Sea, the discovery and rapid initial spread of the North American wedge clam Rangia cuneata represents a new wave of invasion which may trigger unpredictable changes of the local benthic communities. In this study we present a species-specific DNA-based marker developed in silico and experimentally tested on environmental samples. Marker specificity and sensitivity were assessed in vitro from water samples containing different mixtures of the target species and other five bivalves currently present in the region: the native Cerastoderma glaucum, Macoma balthica and Mytilus trossulus, the invasive Dreissena polymorpha and the cryptogenic Mya arenaria. Cross-species amplification was not found in any case. The method allows to detecting at least 0.4 ng of Rangia cuneata DNA per μl, and 0.1 g of tissue per liter of water. Finally, the marker performance was assessed in water samples from the Baltic Sea and Vistula Lagoon. The coincidence between independent visual observations of Rangia cuneata and positive PCR amplification of the marker from the water samples confirmed the efficiency of this highly reproducible, fast, and technically easy method. Rangia cuneata traces can be detected from environmental DNA even when the population is sparse and small, enabling rapid management responses and allowing to track the invasion dynamics