Trace metal concentrations in southern right whale (Eubalaena australis) at Península Valdés, Argentina

Metals and metalloids in green turtle hepatic tissue (Chelonia mydas) from Santos Basin, Brazil

Metal and metalloid concentrations in the liver tissue of green turtles (Chelonia mydas) stranded on the Brazilian coast (n = 506) were studied using inductively coupled plasma mass spectrometry and cold vapor atomic fluorescence spectrometry. The influences of occurrence registers (date and location) and biological characteristics (sex, age, and developmental stage) were assessed, as well as the temporal influences of oil exploration and production activities. The mean concentrations of Cd, Cu, Mn, Zn, and Hg were the highest reported for the liver of C. mydas on the Brazilian coast. The mean element concentrations followed the order: Cu > Zn > Cd > Mn > As > Hg > Mo > Pb > V > Ni > Ba > Cr. Further, significant differences (p < 0.05) were observed for Hg between the sexes (males > females) and for As, Cu, Pb, Mo, and V between young individuals and older individuals (≥11 years), suggesting a relationship between the dietary shift inherent to green turtle development. These results were corroborated by the curved carapace length (CCL) data, wherein individuals residing in coastal areas (CCL > 50 cm) presented higher concentrations of Cu, Pb, Mo, Zn, Ba, and V than those in the oceanic stage (CCL < 30 cm). The opposite pattern was observed for As and Hg. The influences of spatial autocorrelation (Moran Index) at a global scale and oil production activities on the element concentrations were not observed. However, five hotspots of high metal concentrations were identified via a local spatial autocorrelation (local indicator of spatial association), existing predominantly in a region of heavy anthropic activity within the sampling area. Further, baseline element concentrations were established at the 95% confidence level. Overall, the developmental stage, which is related to feeding habits, had an expressive influence on element concentrations.

Using remote sensing to detect whale strandings in remote areas: The case of sei whales mass mortality in Chilean Patagonia

We test the ability of Very High Resolution satellite (VHR) imagery to detect stranded whales using both manual and automated methods. We use the 2015 mass mortality event in the Gulf of Penas locality, central Patagonia, Chile, as an initial case study. This event was the largest known mass mortality of baleen whales, with at least 343 whales, mainly sei whales (Balaenoptera borealis), documented as stranding. However, even with such a large number of whales, due to the remote location of the gulf the strandings went unrecorded for several weeks. Aerial and boat surveys of the area were conducted two to four months after the mortality event. In this study we use 50cm resolution WorldView2 imagery to identify and count strandings from two archival images acquired just after the stranding event and two months before the aerial and ground surveys, and to test manual and automated methods of detecting stranded whales. Our findings show that whales are easily detected manually in the images but due to the heterogeneous colouration of decomposing whales, spectral indices are unsuitable for automatic detection. Our satellite counts suggest that, at the time the satellite images were taken, more whales were stranded than recorded in the aerial survey, possibly due to the non-comprehensive coverage of the aerial survey or movement of the carcases between survey acquisition. With even higher resolution imagery now available, satellite imagery may be a cost effective alternative to aerial surveys for future assessment of the extent of mass whale stranding events, especially in remote and inaccessible areas.

POPs in the South Latin America: Bioaccumulation of DDT, PCB, HCB, HCH and Mirex in blubber of common dolphin (Delphinus delphis) and Fraser's dolphin (Lagenodelphis hosei) from Argentina

Organic compounds, in particular organochlorines, are highly persistent compounds which accumulate in biotic and abiotic substrates. Marine mammals bioaccumulate and biomagnify persistent organic pollutants (POPs) through diet. ∑PCB (26 PCB congeners), ∑DDT (pp-DDT, pp-DDD, pp-DDE), ∑HCH (α-HCH, β-HCH, γ-HCH, δ-HCH), HCB and mirex were analyzed from samples of subcutaneous adipose tissue of common dolphins, Delphinus delphis, and Fraser's dolphins, Lagenodelphis hosei, obtained in 1999 and 2012. The aim of this study was to determine the concentrations of POPs to get baseline information on the current state of pollution by these compounds in these two species in South Atlantic. At the same time, to assess concentrations of POPs in relation to age, the total length and sexual maturity in common dolphins. Organochlorine pesticides dominated Fraser's dolphins, DDT being the most abundant, while PCBs were mostly present in common dolphins. In both species, the distributions of isomers or metabolites followed the order: β-HCH>δ-HCH>γ-HCH>α-HCH and pp-DDE>pp-DDD>pp-DDT. As for ∑PCB, the largest contribution was given by congeners of high molecular weight, particularly by hexa and hepta - CBs. Common dolphins did not show effects on sexual maturity, age and standard length in the concentration of organochlorines. The mean concentrations found in this study are lower compared to those reported in other studies performed in dolphins elsewhere. This study provides new information regarding levels of organochlorines in common dolphins for the Southwestern Atlantic.

Post-mortem findings in southern right whales Eubalaena australis at Península Valdés, Argentina, 2003-2012

Between 2003 and 2012, 605 southern right whales (SRW; Eubalaena australis) were found dead along the shores of Península Valdés (PV), Argentina. These deaths included alarmingly high annual losses between 2007 and 2012, a peak number of deaths (116) in 2012, and a significant number of deaths across years in calves-of-the-year (544 of 605 [89.9%]; average = 60.4 yr(-1)). Post-mortem examination and pathogen testing were performed on 212 whales; 208 (98.1%) were calves-of-the-year and 48.0% of these were newborns or neonates. A known or probable cause of death was established in only a small number (6.6%) of cases. These included ship strike in a juvenile and blunt trauma or lacerations (n = 5), pneumonia (n = 4), myocarditis (n = 2), meningitis (n = 1), or myocarditis and meningitis (n = 1) in calves. Ante-mortem gull parasitism was the most common gross finding. It was associated with systemic disease in a single 1-2 mo old calf. Immunohistochemical labeling for canine distemper virus, Toxoplasma gondii and Brucella spp., and PCR for cetacean morbillivirus (CeMV), influenza A, and apicomplexan protozoa were negative on formalin-fixed, paraffin-embedded lung and brain samples from a subset of whales; PCR for Brucella spp. was positive in a newborn/neonate with pneumonia. Skin samples from whales with gull parasitism were PCR negative for CeMV, poxvirus, and papillomavirus. This is the first long-term study to investigate and summarize notable post-mortem findings in the PV SRW population. Consistent, significant findings within or between years to explain the majority of deaths and those in high-mortality years remain to be identified.

Organochlorine pesticides and PCBs in Southern Right Whales (Eubalaena australis) breeding at Península Valdés, Argentina

Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were assessed in blubber from 35 dead Southern Right Whales (SRW - Eubalaena australis) stranded at Península Valdés, Argentina. The life cycle includes a feeding period in high productivity areas of the South West Atlantic and a reproductive period in coastal template waters of Argentina. Organochlorine pesticides showed higher concentrations (22.6±13.8 ng·g(-1)ww) than PCBs (7.5±10 ng·g(-1)ww). Among pesticides, HCHs, DDTs, endosulfans, dieldrin, chlordans, heptachlor epoxide, and trans-nonachlor were detected. p,p'-DDE and p,p'-DDT were present in 69% and 26% of samples, respectively. p,p'-DDT/p,p'-DDE ratio showed low values (<0.33) as a result of aged DDT inputs. However, the occurrence of only p,p'-DDT in some samples suggests a recent pesticide input. α-HCH/γ-HCH ratio (<DL-0.37) indicated no recent contribution of technical HCH mixture and/or current use of lindane. Dieldrin was present in 77% of the samples and endosulfan was detected in all samples with predominance of α- (75%) over β-endosulfan (19%) and scarce contribution of endosulfan sulphate (7%), suggesting a recent input of this insecticide to the environment in the SRW foraging area. A predominance of pentachlorobiphenyls was observed. In 21 samples at least one PCB indicator was found and PCB #118, highly toxic, contributed in 5% to total PCBs. Although all these organochlorine compounds are forbidden they were bioaccumulated in the blubber of SRW with a predominance of endosulfans, the more recently used pesticide. The absence of data on chemical pollutants in stranded dead whales is highlighted as a priority for research. This is the first study on levels, compositional patterns, and organochlorine sources in SRW. Moreover, more research including milk, and other tissues/organs is recommended considered that in the studied specimens, mostly calves, pollutants are likely transferred from the mother during pregnancy and nursing.