The Experts below are selected from a list of 810 Experts worldwide ranked by ideXlab platform
Mariano Sironi - One of the best experts on this subject based on the ideXlab platform.
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Anthropogenic debris in the digestive tract of a southern right whale (Eubalaena australis) stranded in Golfo Nuevo, Argentina.
Marine pollution bulletin, 2020Co-Authors: Lucia Alzugaray, Victoria J Rowntree, Lucas Beltramino, Mariano Sironi, M. Di Martino, Marcela UhartAbstract:Abstract Over the past fifty years, interactions between anthropogenic debris and a wide range of marine species have increased. In cetaceans, the most frequent interactions have occurred through ingestion and/or entanglement, with results ranging from minor injuries to death in affected animals. While debris ingestion is widely documented in odontocetes, records are scarcer in mysticetes. This study describes the finding of plastic litter in the digestive tract of a southern right whale (Eubalaena australis) juvenile male, which was found dead on the shores of Golfo Nuevo, Chubut, Argentina in 2014. During the examination of intestinal contents, anthropogenic waste was found and classified as macro-debris (25 mm-1 m). Although this whale likely died of causes not related to this finding, it is the first record of anthropogenic debris ingestion for this species. This event adds information about the potential impact of human-made debris on a variety of aquatic species and ecosystems.
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The use of underwater viewing deck of the semi-submersible whalewatching vessel Yellow Submarine at Península Valdés, Argentina as a platform of opportunity for scientifc research with the southern right whale, Eubalaena australis
Latin American Journal of Aquatic Mammals, 2019Co-Authors: Mariano Sironi, Lucia Alzugaray, Agustina Saez, Florencia Ornela Vilches, Alejandro Fernández Ajó, Paula FaifermanAbstract:Whale-watching vessels can be used as platforms to collect scientific data on the natural history of cetaceans. Vessels with underwater viewing decks are exceptional and offer a unique view of the whales. We assessed the underwater viewing platform of the semi-submersible vessel Yellow Submarine that operates off Puerto Piramides, Peninsula Valdes, Argentina as a platform of opportunity for southern right whale ( Eubalaena australis ) research. The variables considered during observations included, among others, the age class and sex of the animals observed, behavioral patterns, opportunities for individual photo-identification, distance and duration of the underwater observations and how weather conditions affected data collection. The Yellow Submarine offers a unique platform to make underwater observations of southern right whales in this calving ground. The main limitations are the relatively short duration of the observations and reduced visibility in spring.
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increased wounding of southern right whale Eubalaena australis calves by kelp gulls larus dominicanus at peninsula valdes argentina
PLOS ONE, 2015Co-Authors: Carina F. Marón, Matías Di Martino, Lucas Beltramino, Andrea D Chirife, Marcela Uhart, Mariano Sironi, Jon Seger, Victoria J RowntreeAbstract:At least 626 southern right whale (Eubalaena australis) calves died at the Peninsula Valdes calving ground, Argentina, between 2003 and 2014. Intense gull harassment may have contributed to these deaths. In the 1970s, Kelp Gulls (Larus dominicanus) began feeding on skin and blubber pecked from the backs of living right whales at Valdes. The frequency of gull attacks has increased dramatically over the last three decades and mother-calf pairs are the primary targets. Pairs attacked by gulls spend less time nursing, resting and playing than pairs not under attack. In successive attacks, gulls open new lesions on the whales’ backs or enlarge preexisting ones. Increased wounding could potentially lead to dehydration, impaired thermoregulation, and energy loss to wound healing. The presence, number and total area of gull-inflicted lesions were assessed using aerial survey photographs of living mother-calf pairs in 1974–2011 (n = 2680) and stranding photographs of dead calves (n = 192) in 2003–2011. The percentage of living mothers and calves with gull lesions increased from an average of 2% in the 1970s to 99% in the 2000s. In the 1980s and 1990s, mothers and calves had roughly equal numbers of lesions (one to five), but by the 2000s, calves had more lesions (nine or more) covering a greater area of their backs compared to their mothers. Living mother-calf pairs and dead calves in Golfo Nuevo had more lesions than those in Golfo San Jose in the 2000s. The number and area of lesions increased with calf age during the calving season. Intensified Kelp Gull harassment at Peninsula Valdes could be compromising calf health and thereby contributing to the high average rate of calf mortality observed in recent years, but it cannot explain the large year-to-year variance in calf deaths since 2000.
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Unexplained recurring high mortality of southern right whale Eubalaena australis calves at Peninsula Valdés, Argentina
Marine Ecology Progress Series, 2013Co-Authors: Victoria J Rowntree, Matías Di Martino, Luciana Musmeci, Luciano La Sala, Nadia Mohamed, Andrea D Chirife, Marcela Uhart, Mariano Sironi, Julian Andrejuk, Denise McalooseAbstract:Hundreds of southern right whale calves Eubalaena australis died on their calving ground at Peninsula Valdes, Argentina from 2003 through 2011. During this period, the number of dead calves increased at a much greater rate than that of living calves over the preceding 32 yr, and with greater inter-annual variation. High mortality events occurred late in the calving seasons of 2005 and 2007, early in the seasons of 2008 and 2009, and were equally divided between early and late in 2010 and 2011. Calves that died late in the seasons of 2005 and 2007 were at least a meter longer (mean 7.3 m) than newborns, indicating that they had grown and presumably were healthy before dying. An unusual number of large calves (>6 m) died early in the seasons of 2008 and 2009, suggesting that a population-wide process (e.g. nutritional stress) affected many mothers including older, larger mothers that tend to give birth to larger calves early in the season. Many tissue samples have been collected and analyzed, but no consistent lesions, pathologic processes or elevated levels of algal biotoxins have been identified to explain these recent mortality events. Here, we document the high mortality events, place them in historical context and describe ongoing efforts to identify their causes. As of 2010, the southern right whale sub-population that calves off Peninsula Valdes was estimated to be less than 20% of its initial size before whaling; the ongoing high mortality of calves will significantly affect its recovery.
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Metal Levels in Southern Right Whales (Eubalaena australis) from Península Valdés, Argentina.
Journal of environmental & analytical toxicology, 2013Co-Authors: Julieta Martino, Mariano Sironi, Sandra S. Wise, Christopher Perkins, John Pierce WiseAbstract:Peninsula Valdes, Argentina, is a nursing ground for a population of southern right whales (Eubalaena australis). In the last two decades this area has been subjected to an increase in population, tourism and industrial growth. This has raised the concern for exposure to chemical contaminants such as metals. In this study we measured nonessential metals (Ag, Al, As, Au, Ba, Be, Co, Cd, Cr, Hg, Li, Ni, Pb, Sb, Sn, Sr, U and Ti), essential metals (Cu, Fe, Mg, Mn, Mo and Zn) and an essential element (Se) in skin biopsies from female southern right whales (n=10). This is the first report on tissue concentrations of metals in adult southern right whales. Overall, tissue values were on the low end of the spectrum and similar to the values reported in studies of mysticetes from other regions. Measured values do not reflect substantial amounts of accumulation and thus serve as a baseline.
Victoria J Rowntree - One of the best experts on this subject based on the ideXlab platform.
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Anthropogenic debris in the digestive tract of a southern right whale (Eubalaena australis) stranded in Golfo Nuevo, Argentina.
Marine pollution bulletin, 2020Co-Authors: Lucia Alzugaray, Victoria J Rowntree, Lucas Beltramino, Mariano Sironi, M. Di Martino, Marcela UhartAbstract:Abstract Over the past fifty years, interactions between anthropogenic debris and a wide range of marine species have increased. In cetaceans, the most frequent interactions have occurred through ingestion and/or entanglement, with results ranging from minor injuries to death in affected animals. While debris ingestion is widely documented in odontocetes, records are scarcer in mysticetes. This study describes the finding of plastic litter in the digestive tract of a southern right whale (Eubalaena australis) juvenile male, which was found dead on the shores of Golfo Nuevo, Chubut, Argentina in 2014. During the examination of intestinal contents, anthropogenic waste was found and classified as macro-debris (25 mm-1 m). Although this whale likely died of causes not related to this finding, it is the first record of anthropogenic debris ingestion for this species. This event adds information about the potential impact of human-made debris on a variety of aquatic species and ecosystems.
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southern right whale Eubalaena australis calf mortality at peninsula valdes argentina are harmful algal blooms to blame
Marine Mammal Science, 2016Co-Authors: Cara Wilson, Victoria J Rowntree, Mónica Susana Hoffmeyer, Spencer E. Fire, Norma Santinelli, Soledad Díaz Ovejero, Viviana A Sastre, Valeria C DagostinoAbstract:Peninsula Valdes (PV) in Argentina is an important calving ground for southern right whales (SRWs, Eubalaena australis). Since 2005, right whale mortality has increased at PV, with most of the deaths (~90%) being calves <3 mo old. We investigated the potential involvement of harmful algal blooms (HABs) in these deaths by examining data that include: timing of the SRW deaths, biotoxins in samples from dead SRWs, abundances of the diatom, Pseudo-nitzschia spp., and the dinoflagellate, Alexandrium tamarense, shellfish harvesting closure dates, seasonal availability of whale prey at PV and satellite chlorophyll data. Evidence of the whales' exposure to HAB toxins includes trace levels of paralytic shellfish toxins (PSTs) and domoic acid (DA) in tissues of some dead whales, and fragments of Pseudo-nitzschia spp. frustules in whale feces. Additionally, whales are present at PV during both closures of the shellfish industry (due to high levels of PSTs) and periods with high levels of Pseudo-nitzschia spp. and A. tamarense. There is a positive statistical relationship between monthly Pseudo-nitzschia densities (but not A. tamarense) and calf deaths in both gulfs of PV.
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increased wounding of southern right whale Eubalaena australis calves by kelp gulls larus dominicanus at peninsula valdes argentina
PLOS ONE, 2015Co-Authors: Carina F. Marón, Matías Di Martino, Lucas Beltramino, Andrea D Chirife, Marcela Uhart, Mariano Sironi, Jon Seger, Victoria J RowntreeAbstract:At least 626 southern right whale (Eubalaena australis) calves died at the Peninsula Valdes calving ground, Argentina, between 2003 and 2014. Intense gull harassment may have contributed to these deaths. In the 1970s, Kelp Gulls (Larus dominicanus) began feeding on skin and blubber pecked from the backs of living right whales at Valdes. The frequency of gull attacks has increased dramatically over the last three decades and mother-calf pairs are the primary targets. Pairs attacked by gulls spend less time nursing, resting and playing than pairs not under attack. In successive attacks, gulls open new lesions on the whales’ backs or enlarge preexisting ones. Increased wounding could potentially lead to dehydration, impaired thermoregulation, and energy loss to wound healing. The presence, number and total area of gull-inflicted lesions were assessed using aerial survey photographs of living mother-calf pairs in 1974–2011 (n = 2680) and stranding photographs of dead calves (n = 192) in 2003–2011. The percentage of living mothers and calves with gull lesions increased from an average of 2% in the 1970s to 99% in the 2000s. In the 1980s and 1990s, mothers and calves had roughly equal numbers of lesions (one to five), but by the 2000s, calves had more lesions (nine or more) covering a greater area of their backs compared to their mothers. Living mother-calf pairs and dead calves in Golfo Nuevo had more lesions than those in Golfo San Jose in the 2000s. The number and area of lesions increased with calf age during the calving season. Intensified Kelp Gull harassment at Peninsula Valdes could be compromising calf health and thereby contributing to the high average rate of calf mortality observed in recent years, but it cannot explain the large year-to-year variance in calf deaths since 2000.
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Southern right whale (Eubalaena australis) calf mortality at Península Valdés, Argentina: Are harmful algal blooms to blame?
Marine Mammal Science, 2015Co-Authors: Cara Wilson, Victoria J Rowntree, A. Viviana Sastre, Mónica Susana Hoffmeyer, Spencer E. Fire, Norma Santinelli, Soledad Díaz Ovejero, Valeria C. D'agostino, Carina F. Marón, Gregory J. DoucetteAbstract:Peninsula Valdes (PV) in Argentina is an important calving ground for southern right whales (SRWs, Eubalaena australis). Since 2005, right whale mortality has increased at PV, with most of the deaths (~90%) being calves
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Unexplained recurring high mortality of southern right whale Eubalaena australis calves at Peninsula Valdés, Argentina
Marine Ecology Progress Series, 2013Co-Authors: Victoria J Rowntree, Matías Di Martino, Luciana Musmeci, Luciano La Sala, Nadia Mohamed, Andrea D Chirife, Marcela Uhart, Mariano Sironi, Julian Andrejuk, Denise McalooseAbstract:Hundreds of southern right whale calves Eubalaena australis died on their calving ground at Peninsula Valdes, Argentina from 2003 through 2011. During this period, the number of dead calves increased at a much greater rate than that of living calves over the preceding 32 yr, and with greater inter-annual variation. High mortality events occurred late in the calving seasons of 2005 and 2007, early in the seasons of 2008 and 2009, and were equally divided between early and late in 2010 and 2011. Calves that died late in the seasons of 2005 and 2007 were at least a meter longer (mean 7.3 m) than newborns, indicating that they had grown and presumably were healthy before dying. An unusual number of large calves (>6 m) died early in the seasons of 2008 and 2009, suggesting that a population-wide process (e.g. nutritional stress) affected many mothers including older, larger mothers that tend to give birth to larger calves early in the season. Many tissue samples have been collected and analyzed, but no consistent lesions, pathologic processes or elevated levels of algal biotoxins have been identified to explain these recent mortality events. Here, we document the high mortality events, place them in historical context and describe ongoing efforts to identify their causes. As of 2010, the southern right whale sub-population that calves off Peninsula Valdes was estimated to be less than 20% of its initial size before whaling; the ongoing high mortality of calves will significantly affect its recovery.
Marcela Uhart - One of the best experts on this subject based on the ideXlab platform.
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Anthropogenic debris in the digestive tract of a southern right whale (Eubalaena australis) stranded in Golfo Nuevo, Argentina.
Marine pollution bulletin, 2020Co-Authors: Lucia Alzugaray, Victoria J Rowntree, Lucas Beltramino, Mariano Sironi, M. Di Martino, Marcela UhartAbstract:Abstract Over the past fifty years, interactions between anthropogenic debris and a wide range of marine species have increased. In cetaceans, the most frequent interactions have occurred through ingestion and/or entanglement, with results ranging from minor injuries to death in affected animals. While debris ingestion is widely documented in odontocetes, records are scarcer in mysticetes. This study describes the finding of plastic litter in the digestive tract of a southern right whale (Eubalaena australis) juvenile male, which was found dead on the shores of Golfo Nuevo, Chubut, Argentina in 2014. During the examination of intestinal contents, anthropogenic waste was found and classified as macro-debris (25 mm-1 m). Although this whale likely died of causes not related to this finding, it is the first record of anthropogenic debris ingestion for this species. This event adds information about the potential impact of human-made debris on a variety of aquatic species and ecosystems.
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Immunofluorescence of strain Manara.
2016Co-Authors: Sylvia Grune Loffler, Marcela Uhart, Virginia Rago, Mara Martinez, Monica Florin-christensen, Graciela Romero, Bibiana BrihuegaAbstract:Immunofluorescence of strain Manara isolated from a kidney sample of a Southern right whale (Eubalaena australis) 40X.
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Isolation of a Seawater Tolerant Leptospira spp. from a Southern Right Whale (Eubalaena australis).
PloS one, 2015Co-Authors: Sylvia Grune Loffler, Marcela Uhart, Virginia Rago, Mara Martinez, Monica Florin-christensen, Graciela Romero, Bibiana BrihuegaAbstract:Leptospirosis is the most widespread zoonotic disease in the world. It is caused by pathogenic spirochetes of the genus Leptospira spp. and is maintained in nature through chronic renal infection of carrier animals. Rodents and other small mammals are the main reservoirs. Information on leptospirosis in marine mammals is scarce; however, cases of leptospirosis have been documented in pinniped populations from the Pacific coast of North America from southern California to British Columbia. We report the isolation of a Leptospira spp. strain, here named Manara, from a kidney sample obtained from a Southern Right Whale (Eubalaena australis) calf, which stranded dead in Playa Manara, Peninsula Valdes, Argentina. This strain showed motility and morphology typical of the genus Leptospira spp. under dark-field microscopy; and grew in Ellinghausen-McCullough-Johnson-Harris (EMJH) medium and Fletcher medium after 90 days of incubation at 28°C. Considering the source of this bacterium, we tested its ability to grow in Fletcher medium diluted with seawater at different percentages (1%, 3%, 5%, 7% and 10% v/v). Bacterial growth was detected 48 h after inoculation of Fletcher medium supplemented with 5% sea water, demonstrating the halophilic nature of the strain Manara. Phylogenetic analysis of 16S rRNA gene sequences placed this novel strain within the radiation of the pathogenic species of the genus Leptospira spp., with sequence similarities within the range 97–100%, and closely related to L. interrogans. Two different PCR protocols targeting genus-specific pathogenic genes (G1-G2, B64I-B64II and LigB) gave positive results, which indicates that the strain Manara is likely pathogenic. Further studies are needed to confirm this possibility as well as determine its serogroup. These results could modify our understanding of the epidemiology of this zoonosis. Until now, the resistance and ability to grow in seawater for long periods of time had been proven for the strain Muggia of L. biflexa, a saprophytic species. To the best of our knowledge, this is the first isolation of a Leptospira sp. from cetaceans. Our phenotypic data indicate that strain Manara represents a novel species of the genus Leptospira, for which the name Leptospira brihuegai sp. nov. is proposed.
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increased wounding of southern right whale Eubalaena australis calves by kelp gulls larus dominicanus at peninsula valdes argentina
PLOS ONE, 2015Co-Authors: Carina F. Marón, Matías Di Martino, Lucas Beltramino, Andrea D Chirife, Marcela Uhart, Mariano Sironi, Jon Seger, Victoria J RowntreeAbstract:At least 626 southern right whale (Eubalaena australis) calves died at the Peninsula Valdes calving ground, Argentina, between 2003 and 2014. Intense gull harassment may have contributed to these deaths. In the 1970s, Kelp Gulls (Larus dominicanus) began feeding on skin and blubber pecked from the backs of living right whales at Valdes. The frequency of gull attacks has increased dramatically over the last three decades and mother-calf pairs are the primary targets. Pairs attacked by gulls spend less time nursing, resting and playing than pairs not under attack. In successive attacks, gulls open new lesions on the whales’ backs or enlarge preexisting ones. Increased wounding could potentially lead to dehydration, impaired thermoregulation, and energy loss to wound healing. The presence, number and total area of gull-inflicted lesions were assessed using aerial survey photographs of living mother-calf pairs in 1974–2011 (n = 2680) and stranding photographs of dead calves (n = 192) in 2003–2011. The percentage of living mothers and calves with gull lesions increased from an average of 2% in the 1970s to 99% in the 2000s. In the 1980s and 1990s, mothers and calves had roughly equal numbers of lesions (one to five), but by the 2000s, calves had more lesions (nine or more) covering a greater area of their backs compared to their mothers. Living mother-calf pairs and dead calves in Golfo Nuevo had more lesions than those in Golfo San Jose in the 2000s. The number and area of lesions increased with calf age during the calving season. Intensified Kelp Gull harassment at Peninsula Valdes could be compromising calf health and thereby contributing to the high average rate of calf mortality observed in recent years, but it cannot explain the large year-to-year variance in calf deaths since 2000.
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Organochlorine pesticides and PCBs in Southern Right Whales (Eubalaena australis) breeding at Península Valdés, Argentina.
Science of The Total Environment, 2015Co-Authors: Pablo J. Torres, Marcela Uhart, K S B Miglioranza, M Gonzalez, M CommendatoreAbstract:Abstract Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were assessed in blubber from 35 dead Southern Right Whales (SRW — Eubalaena australis ) stranded at Peninsula Valdes, 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 ( p , p ′-DDT in some samples suggests a recent pesticide input. α-HCH/γ-HCH ratio (
Denise Mcaloose - One of the best experts on this subject based on the ideXlab platform.
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symbiotic microbes and potential pathogens in the intestine of dead southern right whale Eubalaena australis calves
Anaerobe, 2019Co-Authors: Carina F. Marón, Matías Di Martino, Andrea D Chirife, Denise Mcaloose, Kevin D Kohl, Mariola Penades Fons, Mauricio A Navarro, Juliann Beingesser, Francisco A Uzal, Denise M DearingAbstract:Abstract Between 2003 and 2017, at least 706 southern right whale (Eubalaena australis) calves died at the Peninsula Valdes calving ground in Argentina. Pathogenic microbes are often suggested to be the cause of stranding events in cetaceans; however, to date there is no evidence supporting bacterial infections as a leading cause of right whale calf deaths in Argentina. We used high-throughput sequencing and culture methods to characterize the bacterial communities and to detect potential pathogens from the intestine of stranded calves. We analyzed small and large intestinal contents from 44 dead calves that stranded at Peninsula Valdes from 2005 to 2010 and found 108 bacterial genera, most identified as Firmicutes or Bacteroidetes, and 9 genera that have been previously implicated in diseases of marine mammals. Only one operational taxonomic unit was present in all samples and identified as Clostridium perfringens type A. PCR results showed that all C. perfringens isolates (n = 38) were positive for alpha, 50% for beta 2 (n = 19) and 47% for enterotoxin (CPE) genes (n = 18). The latter is associated with food-poisoning and gastrointestinal diseases in humans and possibly other animals. The prevalence of the cpe gene found in the Valdes’ calves is unusually high compared with other mammals. However, insufficient histologic evidence of gastrointestinal inflammation or necrosis (the latter possibly masked by autolysis) in the gut of stranded calves, and absence of enterotoxin detection precludes conclusions about the role of C. perfringens in calf deaths. Further work is required to determine whether C. perfringens or other pathogens detected in this study are causative agents of calf deaths at Peninsula Valdes.
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Post-mortem findings in southern right whales Eubalaena australis at Península Valdés, Argentina, 2003-2012.
Diseases of Aquatic Organisms, 2016Co-Authors: Denise Mcaloose, M. Virginia Rago, Matías Di Martino, Sarah H. Olson, Lucas Beltramino, Luciana M. Pozzi, Luciana Musmeci, Luciano La Sala, Andrea D Chirife, Nadia MohamedAbstract:Between 2003 and 2012, 605 southern right whales (SRW; Eubalaena australis) were found dead along the shores of Peninsula Valdes (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 ca- nine 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 be- tween years to explain the majority of deaths and those in high-mortality years remain to be identified.
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Unexplained recurring high mortality of southern right whale Eubalaena australis calves at Peninsula Valdés, Argentina
Marine Ecology Progress Series, 2013Co-Authors: Victoria J Rowntree, Matías Di Martino, Luciana Musmeci, Luciano La Sala, Nadia Mohamed, Andrea D Chirife, Marcela Uhart, Mariano Sironi, Julian Andrejuk, Denise McalooseAbstract:Hundreds of southern right whale calves Eubalaena australis died on their calving ground at Peninsula Valdes, Argentina from 2003 through 2011. During this period, the number of dead calves increased at a much greater rate than that of living calves over the preceding 32 yr, and with greater inter-annual variation. High mortality events occurred late in the calving seasons of 2005 and 2007, early in the seasons of 2008 and 2009, and were equally divided between early and late in 2010 and 2011. Calves that died late in the seasons of 2005 and 2007 were at least a meter longer (mean 7.3 m) than newborns, indicating that they had grown and presumably were healthy before dying. An unusual number of large calves (>6 m) died early in the seasons of 2008 and 2009, suggesting that a population-wide process (e.g. nutritional stress) affected many mothers including older, larger mothers that tend to give birth to larger calves early in the season. Many tissue samples have been collected and analyzed, but no consistent lesions, pathologic processes or elevated levels of algal biotoxins have been identified to explain these recent mortality events. Here, we document the high mortality events, place them in historical context and describe ongoing efforts to identify their causes. As of 2010, the southern right whale sub-population that calves off Peninsula Valdes was estimated to be less than 20% of its initial size before whaling; the ongoing high mortality of calves will significantly affect its recovery.
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Severe soft tissue ossification in a southern right whale Eubalaena australis
Diseases of aquatic organisms, 2012Co-Authors: Luciano F. La Sala, Luciana M. Pozzi, Luciana Musmeci, Denise Mcaloose, Frederick S. Kaplan, Eileen M. Shore, Erwin J. O. Kompanje, Inga F. Sidor, Marcela UhartAbstract:The carcass of a stranded southern right whale Eubalaena australis, discovered on the coast of Golfo Nuevo in Peninsula Valdes, Argentina, exhibited extensive orthotopic and heterotopic ossification, osteochondroma-like lesions, and early degenerative joint disease. Extensive soft tissue ossification led to ankylosis of the axial skeleton in a pattern that, in many respects, appeared more similar to a disabling human genetic disorder, fibrodysplasia ossificans progressiva (FOP), than to more common skeletal system diseases in cetaceans and other species. This is the first reported case of a FOP-like condition in a marine mammal and raises important questions about conserved mechanisms of orthotopic and heterotopic ossification in this clade.
Mónica Susana Hoffmeyer - One of the best experts on this subject based on the ideXlab platform.
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The seasonal dynamics of plankton communities relative to the foraging of the southern right whale (Eubalaena australis) in northern Patagonian gulfs, Península Valdés, Argentina
Continental Shelf Research, 2018Co-Authors: Valeria C. D'agostino, Norma Santinelli, Viviana Sastre, Mariana Degrati, Silvana L. Dans, Mónica Susana HoffmeyerAbstract:Abstract This is the first exploratory study that addresses simultaneously the phytoplankton and mesozooplankton seasonal dynamics associated with some environmental factors in the northern Patagonian gulfs: Golfo Nuevo (GN) and Golfo San Jose GSJ), Argentina, during an annual cycle (December 2014–2015 and January 2015–2016, respectively). It also reports data on mesozooplankton composition and abundance in a sample collected while southern right whales (Eubalaena australis) were feeding at the sea surface in Bahia Piramide (GN). The phytoplankton community was represented by 69 taxa in GN and by 83 taxa in GSJ. In GN, phytoplankton was mainly dominated by diatoms and dinoflagellates whereas in GSJ diatoms dominated the phytoplankton community throughout the year. In GN, the highest phytoplankton biomass and density values were registered during austral spring, 2015 which coincided with a Pseudo-nitzschia australis bloom. In contrast, the lowest biomass values, which were associated with elevated abundances of dinoflagellates, were observed in late spring 2014. In GSJ, the highest biomass values showed two equal peaks in austral autumn and spring 2015. The latter was associated with the maximum cell density recorded in this gulf during a Chaetoceros debilis bloom. In contrast, the lowest biomass values were recorded in winter 2015. Mesozooplankton was represented by 63 taxa in GN and by 61 taxa in GSJ. In GN, this community was mainly represented by cladocerans and copepods, whereas it was dominated by copepods in GSJ. The lowest mesozooplankton abundances were recorded in austral winter in both gulfs. In GN, the highest abundances were recorded in austral summer and spring 2015, whereas in GSJ, the maximum mesozooplankton abundances were observed during austral summer and autumn 2015. The major prey items for E. australis were the copepods Calanoides carinatus, Ctenocalanus vanus, Calanus australis, and Paracalanus parvus, zoeae of the squat lobster Munida gregaria, calyptopis and furcilia of Euphausia lucens, and fish eggs and larvae. In both gulfs, the warm seasons were mainly characterized by higher relative abundances of diatoms, while the cold seasons were mostly associated with higher abundances of dinoflagellates and Dictyochophyceae. Salinity and phaeopigments were related with copepod and appendicularian abundances, whereas surface sea water temperature seemed to modulate the seasonal distribution pattern of cladocerans and decapods.
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domoic acid in a marine pelagic food web exposure of southern right whales Eubalaena australis to domoic acid on the peninsula valdes calving ground argentina
Harmful Algae, 2017Co-Authors: Valeria C Dagostino, Norma Santinelli, Viviana Sastre, Mariana Degrati, Bernd Krock, Torben Krohn, Silvana Laura Dans, Mónica Susana HoffmeyerAbstract:The gulfs that surround Peninsula Valdes (PV), Golfo Nuevo and Golfo San Jose in Argentina, are important calving grounds for the southern right whale Eubalaena australis. However, high calf mortality events in recent years could be associated with phycotoxin exposure. The present study evaluated the transfer of domoic acid (DA) from Pseudo-nitzschia spp., potential producers of DA, to living and dead right whales via zooplanktonic vectors, while the whales are on their calving ground at PV. Phytoplankton and mesozooplankton (primary prey of the right whales at PV and potential grazers of Pseudo-nitzschia cells) were collected during the 2015 whale season and analyzed for species composition and abundance. DA was measured in plankton and fecal whale samples (collected during whale seasons 2013, 2014 and 2015) using liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS). The genus Pseudo-nitzschia was present in both gulfs with abundances ranging from 4.4 x 102 and 4.56 x 105 cell l -1. Pseudo-nitzschia australis had the highest abundance with up to 4.56 x 105 cell l-1. DA in phytoplankton was generally low, with the exception of samples collected during a P. australis bloom. No clear correlation was found between DA in phytoplankton and mesozooplankton samples. The predominance of copepods in mesozooplankton samples indicates that they were the primary vector for the transfer of DA from Pseudo-nitzschia spp. to higher trophic levels. High levels of DA were detected in four whale fecal samples (ranging from 0.30 to 710 mg g-1 dry weight of fecal sample or from 0.05 and 113.6 mg g-1 wet weight assuming a mean water content of 84%). The maximum level of DA detected in fecal samples (710 mg DA g-1 dry weight of fecal sample) is the highest reported in southern right whales to date. The current findings demonstrate for the first time that southern right whales, E. australis, are exposed to DA via copepods as vectors during their calving season in the gulfs of PV.
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southern right whale Eubalaena australis calf mortality at peninsula valdes argentina are harmful algal blooms to blame
Marine Mammal Science, 2016Co-Authors: Cara Wilson, Victoria J Rowntree, Mónica Susana Hoffmeyer, Spencer E. Fire, Norma Santinelli, Soledad Díaz Ovejero, Viviana A Sastre, Valeria C DagostinoAbstract:Peninsula Valdes (PV) in Argentina is an important calving ground for southern right whales (SRWs, Eubalaena australis). Since 2005, right whale mortality has increased at PV, with most of the deaths (~90%) being calves <3 mo old. We investigated the potential involvement of harmful algal blooms (HABs) in these deaths by examining data that include: timing of the SRW deaths, biotoxins in samples from dead SRWs, abundances of the diatom, Pseudo-nitzschia spp., and the dinoflagellate, Alexandrium tamarense, shellfish harvesting closure dates, seasonal availability of whale prey at PV and satellite chlorophyll data. Evidence of the whales' exposure to HAB toxins includes trace levels of paralytic shellfish toxins (PSTs) and domoic acid (DA) in tissues of some dead whales, and fragments of Pseudo-nitzschia spp. frustules in whale feces. Additionally, whales are present at PV during both closures of the shellfish industry (due to high levels of PSTs) and periods with high levels of Pseudo-nitzschia spp. and A. tamarense. There is a positive statistical relationship between monthly Pseudo-nitzschia densities (but not A. tamarense) and calf deaths in both gulfs of PV.
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Southern right whale (Eubalaena australis) calf mortality at Península Valdés, Argentina: Are harmful algal blooms to blame?
Marine Mammal Science, 2015Co-Authors: Cara Wilson, Victoria J Rowntree, A. Viviana Sastre, Mónica Susana Hoffmeyer, Spencer E. Fire, Norma Santinelli, Soledad Díaz Ovejero, Valeria C. D'agostino, Carina F. Marón, Gregory J. DoucetteAbstract:Peninsula Valdes (PV) in Argentina is an important calving ground for southern right whales (SRWs, Eubalaena australis). Since 2005, right whale mortality has increased at PV, with most of the deaths (~90%) being calves
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Potentially toxic Pseudo-nitzschia species in plankton and fecal samples of Eubalaena australis from Península Valdés calving ground, Argentina
Journal of Sea Research, 2015Co-Authors: Valeria C. D'agostino, Mónica Susana Hoffmeyer, Gastón O. Almandoz, Viviana Sastre, Mariana DegratiAbstract:Abstract Peninsula Valdes (PV) in Argentina is an important calving ground for the southern right whale Eubalaena australis. However, a high mortality of calves has been observed in the last years, which could be associated with phycotoxin exposure. During a sampling program conducted late in the calving seasons of 2004, 2005 and 2010, potentially toxic species of the genus Pseudo-nitzschia were observed to be an important component of the phytoplankton community and they were also found in fecal samples of two live whales and three stranded whales. In line with this, in the present study Pseudo-nitzschia australis, Pseudo-nitzschia fraudulenta, Pseudo-nitzschia pungens and the complex Pseudo-nitzschia pseudodelicatissima were identified in fecal samples and phytoplankton samples by light and electron microscopy. Although no toxin analysis was carried out in the present study, our findings suggest that E. australis could be exposed to domoic acid in their calving ground.