Ocean warming, acidification, and deoxygenation are expected to intensify without significant climate mitigation. In the tropics, rising ocean temperatures may push marine species to their thermal limits, leading to redistributions and cascading effects on communities and ecosystems. We evaluate how future climate change scenarios could impact the habitat suitability of an endemic species of the western tropical Atlantic Ocean, the Guiana dolphin, Sotalia guianensis. Using data from systematic surveys conducted between 1987 and 2023 complemented by open-source databases, we built the most comprehensive occurrence dataset for the species and developed ensemble Species Distribution Models to predict future distributions under the latest CMIP6 projected scenarios-'optimistic' (SSP1-2.6), 'intermediate' (SSP2-4.5), 'pessimistic' (SSP5-8.5)-using expert knowledge to validate model predictions in the present. Our models project substantial range contractions under all climate scenarios. By 2070, under the pessimistic scenario, suitable habitat is expected to decline by 46.9 %, nearly doubling the habitat loss projected under the optimistic scenario (23 %). Guiana dolphins are expected to lose habitat in northeastern Brazil and along the Caribbean coast (except Costa Rica). Remaining suitable areas are expected to become fragmented and confined to southeastern and southern Brazil, where the coastal zone is the most urbanized and degraded. Currently, only 21.6 % of the predicted Guiana dolphin range overlaps with Marine Protected Areas (MPAs), and just 1.8 % is covered by MPAs that prohibit extractive activities-a small proportion expected to decline from 19 % to 14 % in the future. Our study highlights the urgent need to incorporate climate change into conservation strategies for coastal tropical marine predators.

Pontoporia blainvillei, commonly known as the Franciscana dolphin, inhabits the coastal waters of South America and is classified as vulnerable and as undergoing significant population declines. This species is generally found in turbid coastal waters, although it is also found in clear waters, as well as marine areas associated with islands and rocky shores. Tumours originating from cholangiocytes have been rarely described in cetaceans, with descriptions limited to cholangiocellular carcinomas. Cholangiocellular adenomas are characterised by the formation of bile ducts and are rarer than cholangiocellular carcinoma. This study described the first report of a tumour originating from cholangiocytes in P. blainvillei, raising concerns on this endangered cetacean's health status and conservation. The underlying causes of this tumour in Franciscana dolphins remain unknown, highlighting the need for further research.

Polyomaviruses (PyVs) are small double-stranded DNA viruses able to infect species across all vertebrate taxa. In cetaceans, PyVs have been reported only in short-beaked common dolphin (Delphinus delphis), common bottlenose dolphin (Tursiops truncatus) and killer whale (Orcinus orca). Herein, we surveyed PyV in 119 cetaceans (29 mysticetes and 90 odontocetes) stranded along the Brazilian coast, from 2002 to 2022, comprising 18 species. DNA extracted from the lungs was tested using a nested PCR targeting the major capsid protein gene of PyV. Polyomavirus was detected in lung samples of 1.7% (2/119) cetaceans: two juvenile female Guiana dolphins (Sotalia guianensis) stranded in Rio de Janeiro (Rio de Janeiro state) and Guriri (Espírito Santo state), in 2018. Both retrieved sequences were identical and presented 93.3% amino acid identity with Zetapolyomavirus delphini, suggesting a novel species. On histopathology, one of the PyV-positive individuals presented basophilic intranuclear inclusion bodies morphologically consistent with polyomavirus in the lungs. Other available tissues from both cases were PyV-PCR-negative; however, both individuals tested positive for Guiana dolphin morbillivirus. To our knowledge, this is the first report of PyV infection in cetaceans of the Southern Hemisphere and the first description of a co-infection with morbillivirus.

Hepatic and pulmonary lesions are common in cetaceans, despite their poorly understood viral etiology. Herpesviruses (HV), adenoviruses (AdV) and hepatitis E virus (HEV) are emerging agents in cetaceans, associated with liver and/or pulmonary damage in mammals. We isolated and molecularly tested DNA for HV and AdV (n = 218 individuals; 187 liver and 108 lung samples) and RNA for HEV (n = 147 animals; 147 liver samples) from six cetacean families. All animals stranded or were bycaught in Brazil between 2001 and 2021. Positive-animals were analyzed by histopathology. Statistical analyses assessed if the prevalence of viral infection could be associated with the variables: species, family, habitat, region, sex, and age group. All samples were negative for AdV and HEV. Overall, 8.7% (19/218) of the cetaceans were HV-positive (4.8% [9/187] liver and 11.1% [12/108] lung), without HV-associated lesions. HV-prevalence was statistically significant higher in Pontoporiidae (19.2%, 10/52) when compared to Delphinidae (4.1%, 5/121), and in southeastern (17.1%, 13/76)—the most industrialized Brazilian region—when compared to the northeastern region (2.4%, 3/126). This study broadens the herpesvirus host range in cetaceans, including its description in pygmy sperm whales (Kogia breviceps) and humpback whales (Megaptera novaeangliae). Further studies must elucidate herpesvirus drivers in cetaceans.

Mercury contamination has been aggravated by emerging environmental issues, such as climate change. Top predators present concerning Hg concentrations once this metal bioaccumulates and biomagnifies. This study evaluated total mercury (THg) concentrations in tissues of 43 franciscanas (Pontoporia blainvillei) from two populations: the Franciscana Management Area (FMA) IIb and FMA IIIa. Animals from FMA IIIa showed mean concentration 5-times and 2.5-times higher in the liver and kidney (4.73 ± 6.84 and 0.52 ± 0.51 µg.g-1, w.w., respectively) than individuals from FMA IIb (0.89 ± 1.04 and 0.22 ± 0.15 µg.g-1, w.w., respectively). This might be due to: (I) individuals sampled from FMA IIIa being larger and older, and/or (II) the area near FMA IIIa presents environmental features leading to higher THg availability. Coastal contamination can affect franciscanas’ health and population maintenance at different levels depending on their life history and, therefore, it should be considered to guide specific conservation actions.

Persistent organic pollutants (POPs) were analyzed in 136 blubber samples of Franciscana dolphins from Brazil (Pontoporia blainvillei), which is the most threatened dolphin in the Southwestern Atlantic. The dolphins were caught by the fishery fleet and collected from 2000 to 2018 in three regions of Sa similar to o Paulo state: northern Sa similar to o Paulo (SPN), central Sa similar to o Paulo (SPC), and southern Sa similar to o Paulo (SPS). The POPs analyzed in this study were polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDTs), Mirex, hexachlorobenzene (HCB), chlordane compounds (CHLs), hexachlorocyclohexane isomers (HCHs), and polybrominated diphenyl ethers (PBDEs). The concentrations ranged from 36 to 7200 ng g-1 lipid weight (lw) and 113-42200 ng g-1 lw for predominant compounds DDTs and PCBs, respectively. Similar profiles of PCB congeners were observed with a predominance of hexachlorinated compounds, representing approximately 50% of the total PCB amount; the highest PCB concentrations were observed from Baixada Santista (SPC) proximate to a highly urbanized and industrial coastal area. Significant differences were observed between the sexes and maturity of dolphins, mainly for PCBs, DDTs, and Mirex. In general, POPs other than HCB in Franciscana dolphins showed downward tem-poral trends, matching the regulatory periods for restricting and/or banning these compounds. Although POP concentrations are declining, PCB levels remain high in small dolphins, suggesting adverse health effects on Franciscanas. As organic contaminants are one of the numerous threats Franciscanas have been vulnerable to along the Brazilian coast, we recommend monitoring POPs levels every five years to check for declining (or stabilizing) trends.

Sooty Tern, Onychoprion fuscatus (Linnaeus 1766), is a rare species along the Brazilian coast due to oceanic habits. We report the first documented record of this species from São Paulo state, southeastern Brazil. The specimen was found beached in Mongaguá municipality. Morphological assessment, necropsy, and histological analysis allowed us to identify species, reproductive state (non-breeding), and sex (male) of this specimen.

and were more solitary. In adult Indo-Pacific humpback dolphins ( Sousa chinensis ), carrying a sponge on their rostrum as a tool was also observed (Parra

Trace elements bioaccumulation patterns can be an important tool to assess differences among cetaceans' populations. In this work, their use as potential chemical markers to differentiate franciscanas (Pontoporia blainvillei) populations was evaluated. Franciscanas were collected from three states in southeastern Brazil, which comprise three different Franciscana Management Areas (FMAs): Espírito Santo (FMA Ia), southern Rio de Janeiro (FMA IIa), and central São Paulo (FMA IIb). The concentrations of As, Cd, Cu, Fe, Hg, Mn and Zn were determined in the muscle, liver and kidney of the animals. Cadmium was the most valuable chemical marker to differentiate stocks, separating at least FMA IIa from the others. The higher Cd levels in FMA IIa, along with dietary information, indicate that the predominant consumption of cephalopods by this population is the main reason for the differences found. Additionally, environmental characteristics of the areas should also be considered as divergent sources of trace elements. Our findings suggest that non-essential trace elements, such as Cd, can be successful markers to differentiate populations. The Mn concentrations in FMA Ia raised concern and must be carefully monitored, as well as other elements that compose the iron ore tailings that have impacted the Espírito Santo coastal area. Additionally, this is the first study to report trace element concentration in the franciscanas from FMA IIa (southern Rio de Janeiro). Trace element concentrations found in franciscanas may represent different contamination levels in their preys and environments, which might pose specific threats to distinct populations. Therefore, our findings are important to characterize and differentiate franciscana populations and to guide precise management and conservation actions for the distinct stocks of this endangered species.

Pontoporia blainvillei (Gervais & d’Orbigny, 1844), the franciscana dolphin, is the most endangered small cetacean in the Western South Atlantic. It is an endemic species with a coastal and estuarine distribution that has been divided into four Franciscana Management Areas (FMAs). We used the mitochondrial DNA control region to conduct a phylogeographic analysis to evaluate the population structure of the franciscana and the influence of paleoceanographic events on its biogeographic history. We found nine populations along the entire distribution (ΦST = 0.41, ΦCT = 0.38, p < 10–5), with estimated migration rates resulting in less than one female per generation. Populations from FMAIII and FMAIV in the south (including the Río de La Plata Estuary) showed higher long-term migration rates and effective population sizes than northern populations. The phylogeographic analysis supports the franciscana origin in the Río de La Plata Estuary, with further dispersal south and northwards. The first lineage split happened around 2.5 Ma, with lineage radiation throughout the Pleistocene until recent fragmentation events shaped current-day populations. We suggest that Pleistocene glaciations influenced the dispersion and population structure of the franciscana. Specifically, that the shift of the Brazil-Malvinas Confluence drove the dispersion northwards. Then, low sea-level periods caused either the isolation in estuarine refugia or local extinctions, followed by re-colonizations.

Persistent organic pollutants (POPs) were analyzed in 137 blubber samples of Franciscana dolphin, Pontoporia blainvillei, collected from 2000 to 2018 in three regions of the state of São Paulo, Brazil: Northern São Paulo (SPN), Central São Paulo (SPC) and Southern São Paulo (SPS) that belong to the Franciscana Management Area (FMA) II. POP contents ranged from 36 to 7,186 and 81 to 42,192 ng g -1 lw for predominant compounds DDTs and PCBs, respectively. Similar profiles of PCB congeners were observed with predominance of hexachlorinated compounds and represented approximately 50% of the total PCB amount.The highest PCB contents observed in the Franciscanas from Baixada Santista (SPC) is related to the proximity of the largest urbanized and industrial region on the coast of São Paulo. SPN also showed relatively high levels of POPs carried from SPC by predominant marine currents towards north. Significant differences were observed between gender and maturity of dolphins mainly for PCBs, DDTs and Mirex. Males showed a decreasing temporal trend for POPs, which is in accordance with the regulatory periods for restricting and/or banning these compounds.

River dolphins are a highly threatened polyphyletic group comprised of four odontocete families: Iniidae, Pontoporiidae, Lipotidae, and Platanistidae, the first two endemic to South America. To address the knowledge gap regarding infectious agents in this cetacean group, we surveyed the presence of herpesviruses by PCR in skin and/or blood samples of live-captured Amazon ( Inia geoffrensis , n = 25) and Bolivian ( Inia boliviensis , n = 22) river dolphins of the Amazon basin and in selected tissue samples of franciscanas ( Pontoporia blainvillei , n = 27) stranded or bycaught in southeastern Brazil. Additionally, available franciscana tissue samples were examined by histopathology. Herpesvirus DNA was amplified in 13 Bolivian river dolphins (59.1%, 95% CI 38.5–79.6%) and 14 franciscanas (51.9%, 95% CI 33.0–70.7%). All Amazon river dolphins were herpesvirus-negative. Two different herpesviruses were found in Bolivian river dolphins: a previously known gammaherpesvirus detected in blood and/or skin samples of all positive individuals and a novel alphaherpesvirus in the skin of one animal. A new gammaherpesvirus was found in several franciscana samples—the first herpesvirus recorded in Pontoporiidae. Intranuclear inclusion bodies consistent with herpesvirus were observed in the lymph node of one franciscana. The high divergence among the obtained herpesviruses and those previously described can be explained by viral-host coevolution, and by the fact that these populations are fairly isolated.

Pontoporia blainvillei or Franciscana is a small cetacean endemic of South Atlantic Ocean and its highlighted as the most endangered species. Despite the necessity to development conservation strategies for Pontoporia blainvillei studies aiming to feature the reproductive biology and morphological characteristics of the genital organs are still scarce. In this context, the aim of this study was describe the morphological aspects of the genital organs of Pontoporia blainvillei . For this purpose, six male specimens of P. blainvillei stranded on the southeast region of Brazil, were used. Initially animals were measured, and the genital organs were collected, dissected and photodocumented. Then, fragments of all collected organs were submitted to microscopic analysis. The male genital organs of P. blainvillei showed similar results described for other cetaceans, such as, topography in abdominal cavity, presence of two testicles with epididymis, fibroelastic penis with sigmoid shape and presence of deferent duct. Moreover, a male uterus non-functional, two vestigial bones that support the penis, one retractor penis muscle and presence of associated muscles that support the entire reproductive apparatus were observed. However, some differences were present, such as, a simple cubic epithelium in the light of the epididymis, a small testicle even in sexually mature animals and absence of prostate, not previously observed in other cetaceans. Therefore, the animals analyzed showed similar features to other cetaceans, however some peculiarities were observed.

Brucella-exposure and infection is increasingly recognized in marine mammals worldwide. To better understand the epidemiology and health impacts of Brucella spp. in marine mammals of Brazil, molecular (conventional PCR and/or real-time PCR), serological (Rose Bengal Test [RBT], Competitive [c]ELISA, Serum Agglutination Test [SAT]), pathological, immunohistochemical (IHC) and/or microbiological investigations were conducted in samples of 129 stranded or by-caught marine mammals (orders Cetartiodactyla [n = 124], Carnivora [n = 4] and Sirenia [n = 1]). Previous serological tests performed on available sera of 27 of the 129 animals (26 cetaceans and one manatee), indicated 10 seropositive cetaceans. Conventional PCR and/or real-time PCR performed in cases with available organs (n = 119) and/or blood or swabs (n = 10) revealed 4/129 (3.1%) Brucella-infected cetaceans (one of them with positive serology; the remaining three with no available sera). Pathological, IHC and/or microbiological analyses conducted in PCR/real-time PCR and/or seropositive cases (n = 13) revealed Brucella-type lesions, including meningitis/meningoencephalitis, pneumonia, necrotizing hepatitis, pericarditis and osteoarthritis in some of those animals, and positive IHC was found in all of them (excepting two live-stranded animals without available organs). Brucella spp. culture attempts were unsuccessful. Our results demonstrated exposure, asymptomatic, acute and chronic Brucella sp. infection in several cetacean species in the Brazilian coast, highlighting the role of this pathogen in stranding and/or death, particularly in Clymene dolphin (Stenella clymene) and short-finned pilot whale (Globicephala macrorhynchus) off Ceará State. Novel hosts susceptible to Brucella included the franciscana (Pontoporia blainvillei), the Guiana dolphin (Sotalia guianensis) and the spinner dolphin (Stenella longirostris). Additionally, three coinfection cases involving Brucella spp. and cetacean morbillivirus, Edwarsiella tarda and Proteus mirabilis were detected. To the best of our knowledge, this is the first long-term and large-scale survey of Brucella spp. in marine mammals of South America, widening the spectrum of susceptible hosts and geographical distribution range of this agent with zoonotic potential.

Toxoplasmosis is a parasitic disease caused by the protozoan Toxoplasma gondii. In cetaceans, T. gondii infection is a significant cause of morbidity and mortality. Despite the worldwide range and broad cetacean host record of T. gondii infection, there is limited information on toxoplasmosis in cetaceans from the Southern hemisphere. We investigated the occurrence of T. gondii by histopathology and immunohistochemistry in tissue samples of 185 animals comprising 20 different cetacean species from Brazil. Three out of 185 (1.6%) animals presented T. gondii-associated lesions: a captive killer whale Orcinus orca, a free-ranging common bottlenose dolphin Tursiops truncatus and a free-ranging Guiana dolphin Sotalia guianensis. The main lesions observed in these animals were necrotizing hepatitis, adrenalitis and lymphadenitis associated with protozoal cysts or extracellular tachyzoites presenting immunolabeling with anti-T. gondii antibodies. This study widens the spectrum of species and the geographic range of this agent in Brazil, and provides the first reports of T. gondii infection in a captive killer whale and in a free-ranging common bottlenose dolphin in South America.

Understanding diet variation is a major concern when developing conservation guidelines for threatened species, especially for marine predators whose prey availability can be reduced by commercial fisheries. Diet can vary in geographically structured populations due to variation in prey availability and within a location due to the effects of season, sex, age, and individual. However, these sources of variation are seldom considered together in dietary studies. We analyzed diet variation at the geographical and intrapopulation levels in the franciscana dolphin (Pontoporia blainvillei) by analyzing samples of stomach contents from individuals incidentally caught by artisanal fisheries. We investigated the geographical (Northern, Central, and Southern regions of the SAo Paulo State coast, Brazil) and intrapopulation effects of season, sex, and age. We used the leave-one-out cross-validation method to test for significance of the proportional similarity index, which measures the overlap between diet compositions. We found that diet varied across different levels, from the geographical to the individual level, including the effects of season, sex, and age. Diet variation as a function of age suggests an ontogenetic diet shift. Our findings indicate that ecological processes within local stocks should inform management at the local geographic scale. Evidence for ecological differences between franciscana stocks is of great significance for the conservation of this threatened species.

Este trabalho apresenta as atividades do Instituto Biopesca, associacao da sociedade sem fins lucrativos, criada em 1998 por um grupo de pesquisadores da area de conservacao ambiental marinha em Praia Grande, municipio do litoral paulista. Nesses 20 anos de existencia, a organizacao ampliou suas atividades que, atualmente, consistem principalmente em Educacao Ambiental (EA), monitoramento pesqueiro, realizacao de pesquisas cientificas e apoio a trabalhos academicos. Sua area de atuacao abrange, principalmente, os municipios de Praia Grande, Mongagua, Itanhaem e Peruibe. Todas as atividades sao, em essencia, voltadas a conservacao da fauna marinha. Palavras-chave : Conservacao; Meio Ambiente; Educacao; Pesquisa. This paper presents the activities of the Instituto Biopesca, a non - profit association created in 1998 by a group of researchers in Praia Grande, a city on the coast of Sao Paulo. Since 1998, the organization has expanded its activities, which currently consist mainly of Environmental Education (EA), monitoring beaches and fishing, conducting scientific research and supporting academic jobs. The area of activity covers, mainly, Praia Grande, Mongagua, Itanhaem and Peruibe. All activities are, in essence, focused on the conservation of marine fauna. Keywords : Conservation; Environmental; Education; Research.

Pontoporia blainvillei (cetacean order and odontoceti suborder), popularly known in Brazil as Toninha, is a small dolphin with a long, thin beak found on the southern shore waters of the western Atlantic. The brain development of dolphins (expressed by the encephalization coefficient) in relation to body size is quite high, and is second only to humans. This high correlation in brain development between dolphins and humans was targeted in this research to describe and compare the morphology of cerebral hemisphere surfaces of these two species. Five brains of Pontoporia blainvillei donated by the BioPesca Project (a non-governmental organization) were analyzed. The brains were fixed in 20% formaldehyde solution for further description and comparison to human brains described in books of neuroanatomy. The telencephalon of Pontoporia blainvillei is rostrally tapered and expanded at the caudal end and it has a greater number of folds/gyrus when compared to human species. Some encephalic grooves/sulcus are similar to grooves found in the human species, such as the cruciate sulcus (central sulcus), lateral fissure (Sylvian cleft), cingulate sulcus and calcarine sulcus. The same encephalic lobes are seen in both species; however the parietal and temporal lobes are highly developed in the Pontoporia blainvillei. These differences are associated with specific function of the species, as the presence of the an efficient auditive system in dolphins.

Many factors threaten the survival of marine turtles, such as incidental capture by fisheries, habitat degradation, pollution and diseases. One of the most important diseases is fibropapillomatosis (FP), characterized by the development of benign skin tumours. FP predominantly affects juvenile green sea turtles (Chelonia mydas) and involves a complex multifactorial aetiology. For several years, it has been noted that the prevalence of FP tends to be higher in marine environments under the influence of human activities, leading to the hypothesis that environmental pollutants play a role in the epidemiology of this disease. Organochlorine compounds (OCs) are persistent organic pollutants with immunosuppressive and carcinogenic effects in humans and wildlife. OC levels (α-BHC, β-BHC, α-endosulphan, β-endosulphan, endosulphan sulphate, pp′-DDD, op′-DDD, pp′-DDE, op′-DDE, heptachlor, dicofol and mirex) were quantified through gas chromatography with a micro-electron capture detector (GC-μECD) in liver and fat samples from 64 juvenile green sea turtles. Specimens with and without FP were analysed, after being caught at three feeding areas off the Brazilian coast: Ubatuba, Praia Grande and Vitória. OC levels were comparable to those observed in similar studies, and no consistent difference was observed between sea turtles with and without FP. This study helps to elucidate the contamination profile in sea turtles caught at feeding areas off Brazil and confirms that green sea turtles are exposed to OCs, which may play a negative role in the health of this species.