McAloose D.,Wildlife Conservation Society |
Rago M.V.,Southern Right Whale Health Monitoring Program |
Rago M.V.,Wildlife Conservation Society |
Di Martino M.,Southern Right Whale Health Monitoring Program |
And 24 more authors.
Diseases of Aquatic Organisms
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). Postmortem examination and pathogen testing were performed on 212 whales; 208 (98.1%) were calvesof- 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, paraffinembedded 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. © The authors 2016. Source
Lundquist D.,Texas A&M University |
Sironi M.,Institute Conservacion Of Ballenas |
Sironi M.,National University of Cordoba |
Wursig B.,Texas A&M University at Galveston |
And 3 more authors.
Marine Mammal Science
Guidelines for sustainable tourism involving swimming with large whales are not well-developed compared to those focused on programs of swimming with delphinids. From September to November 2005 and August to September 2006, we collected behavioral and movement data for southern right whales (Eubalaena australis) exposed to interactions with boats and swimmers at Península Valdés, Argentina. Whales were tracked from shore using a theodolite before, during, and after a series of directed interactions with swimmers and a boat. Resting, socializing, and surface active behavior decreased, traveling increased, and whales swam faster and reoriented more often during interactions. Responses were variable by age/sex class, with mother/calf pairs showing strongest responses. Increased levels of tourism activity are a concern, as reduction in resting time and disruption of socialization among adults, juveniles, and mother/calf pairs have unknown long-term consequences. Additional data should be collected for whale behavior in proposed tourism and nontourism areas to build a long-term database which can be used to determine if reactions of whales change over time. Our data suggest that swimming with whales in Chubut Province should not be legalized until further investigations are completed, especially in light of the recent southern right whale die-offs recorded in Península Valdés. © 2012 by the Society for Marine Mammalogy. Source
Valenzuela L.O.,University of Utah |
Valenzuela L.O.,Institute Conservacion Of Ballenas |
Sironi M.,Institute Conservacion Of Ballenas |
Sironi M.,National University of Cordoba |
And 2 more authors.
Lactation is the most energetically expensive aspect of mammalian reproduction. As capital breeders, lactating southern right whales (Eubalaena australis) are completely dependent on their stored nutrients. The relative proportion of different endogenous nutrient pools used during lactation could be assessed using stable isotopes. We determined the stable carbon and nitrogen isotope difference between skin samples of 42 southern right whale mothers and their calves. The mean δ15N value of calves was 0.51‰ higher than that of their mothers, but their δ13C values were identical. However, when analyzed by year, the mother-calf pairs showed no isotope differences in 2004, but calves had higher δ15N (0.85‰) and δ13C (0.63‰) in 2003 and 2005. We hypothesize that the inter-annual variability was a consequence of different levels of nutritional stress. A decline in food abundance prior to the nursing seasons could result in mothers with relatively poorer physical condition that would not be able to meet the high energetic demands of their offspring. Thus, the calves would be forced to utilize proteins as well as lipids to meet this demand, increasing their nitrogen and carbon isotope ratios. This hypothesis is supported by an independent assessment of the proportion of stranded whales over the same time period. Source
Rowntree V.J.,Southern Right Whale Health Monitoring Program |
Rowntree V.J.,University of Utah |
Rowntree V.J.,Whale Conservation Institute Ocean Alliance |
Rowntree V.J.,Institute Conservacion Of Ballenas |
And 21 more authors.
Marine Ecology Progress Series
Hundreds of southern right whale calves Eubalaena australis died on their calving ground at Península Valdés, 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 Península Valdés was estimated to be less than 20% of its initial size before whaling; the ongoing high mortality of calves will significantly affect its recovery. © Inter-Research 2013. Source
Maron C.F.,University of Utah |
Maron C.F.,Institute Conservacion Of Ballenas |
Beltramino L.,Programa de Monitoreo Sanitario Ballena Franca Austral |
Di Martino M.,Programa de Monitoreo Sanitario Ballena Franca Austral |
And 9 more authors.
At least 626 southern right whale (Eubalaena australis) calves died at the Península Valdés 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 Valdés. 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 José in the 2000s. The number and area of lesions increased with calf age during the calving season. Intensified Kelp Gull harassment at Península Valdés 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. © 2015 Marón et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Source