Microplastics in the stomach contents of common dolphin (Delphinus delphis) stranded on the Galician coasts (NW Spain, 2005–2010)

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Microbiota fingerprints within the oral cavity of cetaceans as indicators for population biomonitoring

The composition of mammalian microbiota has been related with the host health status. In this study, we assessed the oral microbiome of 3 cetacean species most commonly found stranded in Iberian Atlantic waters (Delphinus delphis, Stenella coeruleoalba and Phocoena phocoena), using 16S rDNA-amplicon metabarcoding. All oral microbiomes were dominated by Proteobacteria, Firmicutes, Bacteroidetes and Fusobacteria bacteria, which were also predominant in the oral cavity of Tursiops truncatus. A Constrained Canonical Analysis (CCA) showed that the major factors shaping the composition of 38 oral microbiomes (p-value < 0.05) were: (i) animal species and (ii) age class, segregating adults and juveniles. The correlation analysis also grouped the microbiomes by animal stranding location and health status. Similar discriminatory patterns were detected using the data from a previous study on Tursiops truncatus, indicating that this correlation approach may facilitate data comparisons between different studies on several cetacean species. This study identified a total of 15 bacterial genera and 27 OTUs discriminating between the observed CCA groups, which can be further explored as microbiota fingerprints to develop (i) specific diagnostic assays for cetacean population conservation and (ii) bio-monitoring approaches to assess the health of marine ecosystems from the Iberian Atlantic basin, using cetaceans as bioindicators.The authors would like to acknowledge to Jorg Becker and Joao Sobral for the sequencing services provided at the Instituto Gulbenkian de Ciencia. This work was supported by the project CetSenti RECI/AAGGLO/0470/2012 (FCOMP-01-0124-FEDER-027472), by the strategic program UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569), by the GenomePT project (POCI-01-0145-FEDER-022184), supported by COMPETE 2020 -Operational Programme for Competitiveness and Internationalisation (POCI), Lisboa Portugal Regional Operational Programme (Lisboa2020), Algarve Portugal Regional Operational Programme (CRESC Algarve2020), under the PORTUGAL 2020 Partnership Agreement, funded by national funds through the Fundacao para a Ciencia e a Tecnologia (FCT) I.P. and the European Regional Development Fund (ERDF), through the COMPETE2020-Programa Operacional Competitividade e Internacionalizacao (POCI). The work was supported as well through CESAM UID/AMB/50017/2013 co-funded by the FCT/MEC and FEDER within PT2020 and Compete 2020 (C.E.), FCT grants SFRH/BD/30240/2006 (M.F.), and SFRH/BPD/82407/2011 (A.L.) and NIH RCMI Grant No. 2U54MD007600 (F.G.V.)

Recent increase of ulcerative lesions caused by Anisakis spp. in cetaceans from the north-east Atlantic

Species of Anisakis typically infect the stomach of cetaceans worldwide, often causing ulcerative lesions that may compromise the host’s health. These nematodes also cause anisakiasis or allergic reactions in humans. To assess the risks of this emerging zoonosis, data on long-term changes in Anisakis infections in cetaceans are necessary. Here, we compare the prevalence and severity of ulcerative lesions caused by Anisakis spp. in five cetacean species stranded along the north-west Spanish coast in 2017–2018 with published data from 1991–1996. Open ulcers were found in 32/ 43 short-beaked common dolphins, Delphinus delphis; 3/5 striped dolphins, Stenella coeruleoalba; 1/7 bottlenose dolphins, Tursiops truncatus; and 1/3 harbour porpoises, Phocoena phocoena mer- idionalis; a single individual of long-finned pilot whale, Globicephala melas, was found unin- fected. In common dolphins, the mean abundance of open ulcers per host was 1.1 (95% confidence interval: 0.8–1.3), with a maximum diameter (mean ± standard deviation) of 25.4 ± 16.9 mm. Stomachs with scars or extensive fibrosis putatively associated with Anisakis were detected in 14 and five animals, respectively. A molecular analysis based on the mitochondrial cytochrome c oxidase II gene using 18 worms from three cetacean species revealed single or mixed infections ofAnisakis simplex sensu stricto and Anisakis pegreffii. Compared with the per- iod 1991–1996, we found a strong increase of prevalence, abundance and extension of ulcerative lesions in most cetacean species. Anisakis populations could have increased in the study area over the last decades, although we cannot rule out that a higher environmental stress has also boosted the pathological effects of these parasites.En prens

Understanding the impacts of contaminant and pathogen flow through marine food webs

ICES Annual Science Conference 2021, 6–10 September, Virtual conferenceN