The deep dive of organohalogen compounds: Bioaccumulation in the top predators of mesopelagic trophic webs, pygmy and dwarf sperm whales, from the Southwestern Atlantic ocean.

Kogia sima and Kogia breviceps are apex predators of mesopelagic trophic webs being far from most anthropogenic threats. However, chemical pollutants and naturally synthesized compounds may travel long distances. This study aimed to use kogiid whales as sentinels of mesopelagic trophic webs in the Southwestern Atlantic Ocean. Persistent organic pollutants (POPs), e.g., polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and metabolites, mirex, hexachlorobenzene (HCB), polybrominated diphenylethers (PBDEs), pentabromoethylbenzene (PBEB) and hexabromobenzene (HBB), and the naturally produced methoxylated BDE (MeO-BDEs) were determined in the blubber of 16 K. sima and 15 K. breviceps. Among the organochlorine compounds, DDTs were the main group found in K. sima and in K. breviceps (1636.6 and 3983.3 ng g-1 lw, respective medians), followed by PCBs (425.9 and 956.1 ng g-1 lw, respectively), mirex (184.1 and 375.6 ng g-1 lw, respectively), and HCB (132.4 and 340.3 ng g-1 lw, respectively). As for the organobromine, the natural MeO-BDEs were predominant (1676.7 and 501.6 ng g-1 lw, respectively), followed by PBDEs (13.6 and 10.3 ng g-1 lw, respectively) and PBEB (2.2 and 2.9 ng g-1 lw, respectively). In general, POPs concentration was higher in K. breviceps than in K. sima. Conversely, MeO-BDEs concentration was higher in K. sima than in K. breviceps. Differences in concentrations in these sympatric odontocetes were attributed to distinct species, sampling sites, and biological parameters and suggest some level of niche segregation. It is noteworthy the long-range reach and bioaccumulation of these synthetic compounds in an unexplored habitat, that present an increasing economic interest.

Skeletal abnormalities in humpback whales Megaptera novaeangliae stranded in the Brazilian breeding ground.

Skeletal tissues of 49 humpback whales Megaptera novaeangliae that stranded between 2002 and 2011 along the Abrolhos Bank seashore and its adjacent waters in Brazil were studied. Twelve (24.5%) animals presented pathological changes in one or more bones. Degenerative changes and developmental malformations were most frequent (10.2% each), followed by inflammatory/infectious and traumatic lesions (8.2% each). Infectious diseases led to severe lesions of the caudal vertebrae of 2 whales. In one of these individuals, the lesions involved 6 caudal vertebrae, leading to ankylosis of 3 vertebrae. Degenerative changes were observed in the vertebral columns of 3 animals, involving the joints of 13 ribs of 1 individual, and in the humerus of 1 whale. Traumatic lesions, such as osseous callus in the ribs, were observed in 4 animals. In 1 whale, the rib showed severe osteomyelitis, possibly resulting from the infection of multiple fractures. Developmental abnormalities such as spina bifida on 3 cervical vertebrae of 1 whale, fusion of spinal processes on thoracic vertebrae of 1 individual and fusion of the first 2 ribs unilaterally or bilaterally in 4 animals were found. Chronic infectious conditions found in the axial skeleton may have restrained spinal mobility and had detrimental effects on the general health of the animals, contributing to stranding and death. To our knowledge, this is the first systematic study on skeletal lesions in stranded humpback whales.

Franciscana dolphins, Pontoporia blainvillei, as environmental sentinels of the world's largest mining disaster: Temporal trends for organohalogen compounds and their consequences for an endangered population.

On November 5th, 2015, the Fundão dam collapsed in Minas Gerais, southeastern Brazil, releasing millions of cubic meters of mud containing mining residue into the Doce River. Two weeks later, the mud arrived to the marine environment, triggering changes in franciscana dolphin habitat, Pontoporia blainvillei, from Franciscana Management Area Ia. This is an isolated population of the most endangered cetacean species in the South Atlantic Ocean. Organohalogen compounds (OHCs) may pose a threat to this endangered population because of their endocrine disrupting properties. Hence, this study sought to determine if there were differences in the bioaccumulation profile of OHC (PCBs, DDTs, Mirex, HCB, HCHs, PBDEs, PBEB, HBBZ and MeO-BDEs) in franciscana dolphins before and after dam collapse and to build a temporal trend. Blubber of 33 stranded individuals was collected in Espírito Santo state for organohalogen assessment between 2003 and 2019. Differences were found between franciscana dolphins collected prior to and after the disaster. Additionally, significant temporal trends for organochlorine pesticides and natural and anthropogenic organobromine were detected. The increase in pesticide concentrations after 2015 is suggestive of their reavailability in the environment. The decline in organobromine over time could be due to their debromination in the marine environment and alterations in the composition of their natural producers. PCBs remained stable during the period of the study. Our findings show an increase in endocrine disruptor concentrations, which is of great concern for this endangered population.

Molecular, serological, pathological, immunohistochemical and microbiological investigation of Brucella spp. in marine mammals of Brazil reveals new cetacean hosts.

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.

Occurrence of Prosthenorchis elegans in Free-living Primates from the Atlantic Forest of Southern Bahia, Brazil.

Parasite prevalence and abundance are important factors affecting species' conservation. During necropsies on a free-living golden-headed lion tamarin ( Leontopithecus chrysomelas ) and two Wied's marmosets ( Callithrix kuhlii ) in the Atlantic Forest of southern Bahia, Brazil, we collected a large number of adult intestinal parasites that we identified as Prosthenorchis elegans. This parasite is pathogenic for neotropical primates. Prosthenorchis spp. infestation is influenced by diet with increased risk of exposure from ingesting invertebrate intermediate hosts. The biological similarities and sympatric nature of these two nonhuman primates support that they may harbor similar infectious and parasitic agents.