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In this study, we investigated for the first time anthropogenic microparticles in the franciscana dolphin Pontoporia blainvillei , the most endangered cetacean of the Southwest Atlantic Ocean. The intestinal content of the proximal and distal sections, and wall tissues of the proximal section of ten female dolphins collected during 2013–2023 were analyzed. All samples contained anthropogenic particles (%FO = 100). Fibers were the most abundant shape (99 %). Micro-Raman and micro-FTIR spectroscopies revealed the presence of polyester, polypropylene, acrylic, polyethylene, and semi-synthetic cotton polymers. Manufactured pigments such as reactive blue 238, Indigo 3600, and diarylide azo pigment (yellow 152) were also detected. We observed variations in the color and types of polymers present in the different sections of the intestine and within the wall tissue, suggesting a differential microplastic absorption. These findings confirm both the presence and absorption of microplastics in the intestines from franciscana dolphins. [Display omitted] • Intestinal contents of P. blainvillei dolphins were analyzed. • FO% of microplastic in all samples was 100 %. • Fibers were the most abundant, followed by films. • Spectroscopies revealed five polymers and four anthropogenic pigments. [ABSTRACT FROM AUTHOR]

Adult Anisakis Dujardin, 1845 were found in two specimens of killer whale Orcinus orca and one specimen of franciscana Pontoporia blainvillei stranded from off the coast of Buenos Aires Province, Argentina. Genetic identification of the nematodes (N = 144) was performed by sequence analysis of the mitochondrial (mtDNA cox2) and the nuclear (nas 10 nDNA) gene loci. Anisakis pegreffii and Anisakis berlandi were detected in the two individuals of O. orca, while Anisakis typica and A. pegreffii were identified in P. blainvillei. Morphological and morphometric analysis also carried out on adult specimens of A. pegreffii and A. berlandi has allowed to underlining the usefulness of genetic/molecular markers in their recognition. This represents the first record of A. pegreffii in O. orca and P. blainvillei and of A. berlandi in O. orca. This is also the first sympatric and syntopic occurrence, as adults, of A. pegreffii and A. berlandi from the Austral Region of the Atlantic Ocean waters. These results provide insights into the knowledge of the host ranges and geographical distribution of these parasites in the basin waters of the region. Pontoporia blainvillei showed low abundance values of infection with Anisakis spp., which is the general pattern for coastal dolphins in the area, whereas O. orca harboured higher abundance of Anisakis spp. than those previously recorded among cetacean species in the Argentine Sea. Differences in the Anisakis spp. distribution and their parasitic loads, observed among the three host specimens, are discussed in relation to the oceanographic parameters, as well as to the host ecology. The usefulness of genetic/molecular markers in the recognition of adults of the sibling species A. pegreffii and A. berlandi with considerable overlapping in morphometric and morphological characters was underlined. The distribution of Anisakis species from Southwestern Atlantic waters is discussed in relation to their value as indicators for studies on the zoogeography of their hosts at a regional-scale level. [ABSTRACT FROM AUTHOR]

In this paper, we examined the ingestion of large marine debris (1 mm–1010 mm) in 21 odontocete species that were found dead or by-caught in low frequency in southern Brazil (Rio Grande do Sul State) and northern Argentina (Buenos Aires) between 1988 and 2020. Eight percent of the total individuals studied (13 out of 156), representing nine species, had ingested marine debris. Most of items were made of plastics (68 %), and within them, single-use plastic (e.g. plastic bags) were the dominant man-made items. Seven of the nine species that had ingested marine debris have been previously registered ingestion of this pollutant in other areas of their distribution. We also incorporated endemic odontocetes of the Southwest Atlantic Ocean to the list of affected marine organisms: the Burmeister's porpoise Phocoena spinipinnis , and the Lahille's bottlenose dolphin, Tursiops gephyreus. • We examined the ingestion of large marine debris (1mm-1010mm in size) in 156 individuals of 21 odontocetes species in southern Brazil and northern Argentina between 1988 and 2020. • Eight percent (8%) of the individuals, representing nine species, ingested marine debris. • Most of items were made of plastic (68%). • Two species are reported ingesting plastic for the first time: Phocoena spinipinnis and Tursiops gephyreus. [ABSTRACT FROM AUTHOR]

Highlights: [•] This is the first report of MT concentrations in Franciscana dolphins. [•] Metal and MT levels were not associated to environmental impact. [•] MT levels correspond to physiological values according to ontogenetic changes. [•] Fetus presented higher levels of MT and essential metals than its mother. [•] There was a trend to decrease MT levels from early to later development stages. [ABSTRACT FROM AUTHOR]

Highlights: [•] Fine scale distribution of two Argentine stocks constrains the Cd accumulation rates. [•] Cadmium levels and accumulation patterns were different between geographic groups. [•] Marine diet has a major influence than the impact degree of origin environment. [•] Engraulis anchoita is the main Cd vector species in Argentine shelf for Franciscana. [•] Information is valuable for the conservation of Franciscana, a vulnerable species. [Copyright &y& Elsevier]

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Abstract: Plastic debris (PD) ingestion was examined in 106 Franciscana dolphins (Pontoporia blainvillei) incidentally captured in artisanal fisheries of the northern coast of Argentina. Twenty-eight percent of the dolphins presented PD in their stomach, but no ulcerations or obstructions were recorded in the digestive tracts. PD ingestion was more frequent in estuarine (34.6%) than in marine (19.2%) environments, but the type of debris was similar. Packaging debris (cellophane, bags, and bands) was found in 64.3% of the dolphins, with a lesser proportion (35.7%) ingesting fishery gear fragments (monofilament lines, ropes, and nets) or of unknown sources (25.0%). PD ingestion correlated with ontogenetic changes in feeding regimes, reaching maximum values in recently weaned dolphins. Because a simultaneous increase in gillnet entanglement and the bioaccumulation of heavy metals take place at this stage, the first months after trophic independence should be considered as a key phase for the conservation of Franciscana dolphin stocks in northern Argentina. [Copyright &y& Elsevier]

The Franciscana dolphin Pontoporia blainvillei is characterized by a long rostrum, a feature that is shared with the families formerly classified as river dolphins (Pontoporiidae, Platanistidae, Iniidae, Lipotidae). Although there are occasional reports on the existence of beak deformations, very little published information exists describing this process. The object of the present study was to describe and quantify the beak anomalies of Franciscana dolphins from the coastal waters of Argentina. Of 239 skulls analyzed 12% showed beak deviations (BD), affecting the premaxillary-maxillary and dentary bones to different extents. The occurrence of BD in the dentary bone represented 58%, whereas premaxillary-maxillary BDs were observed in 14% of the studied specimens, while the complete rostrum (dentary, premaxillary and maxillary) was affected in 28% of the skulls. Dorsoventral axis BD was more frequent than lateral BD (48 and 38%, respectively), and double BD was only observed in the dentary bone. Most of the BD observed in this study could be classified as mild/moderate, and we assume that it did not affect the feeding activities of individuals; however, 2 specimens (<1%) showed a severe and complex curvature that probably did affect them. The cause of these anomalies (natural or anthropogenic origins) is unknown but may be related to important parasite loads, heavy metal and organic contaminants and plastic ingestion that could affect the coastal dolphin in different ways. A more detailed and thorough study of these cranial anomalies is necessary.