Review of lobomycosis and lobomycosis-like disease (LLD) in Cetacea from South America. Scientific Committee document SC/60/DW13, International Whaling Commission, June 2008, Santiago, Chile

Caused by a yeast-like organism known as Lacazia loboi, Lobomycosis (or lacaziosis) naturally affects humans, common bottlenose dolphins (Tursiops truncates) inhabiting coastal waters from southern Brazil to Gulf of Mexico and Atlantic coast of Florida, as well as botos-cinza (Sotalia guianensis). These species are usually found in coastal waters, subject to runoff provided by large rivers and a considerable burden of associated contaminants. Histological and morphological studies demonstrated that the etiological agent of L. loboi infecting humans is different from the one found to infected dolphins. Moreover, it likely that dolphin-human infections do not occur although infected bottlenose dolphins were from populations engaged in cooperative fishing that involve a relative small number of dolphins and humans. The records of Lobomycosis and Lobomycosis-like disease (LLD) in Tramandaí estuary (29o58´S), Rio Grande do Sul, Brazil, represent the southernmost distribution of L. loboi. On the other hand, the northernmost distribution of this disease is reported in the southern portion of Indian River Lagoon (27°25´N), Florida, USA. LLD seems to be more widespread, infecting both toothed small cetaceans and baleen whales, from the tropical Atlantic to the Pacific. Future studies should evaluate the association with impaired immune function in affected dolphins and the emergency of Lobomycosis. It may be associated with an immunosuppressive factor of environmental origin, such as exposure to pesticides or other agricultural or industrial contaminants, introduced through runoff or point sources of pollution, altering conditions to favour disease emergence. Lobomycosis should be assigned as neglected tropical disease, as should be the case of LLD, if future investigations indicate their connection as an emerging pathogen, its pathogenicity and environment requirements

A preliminary overview of skin and skeletal diseases and traumata in small cetaceans from South American waters

We succinctly review and document new cases of diseases of the skin and the skeletal system and external traumata in cetaceans from Ecuador, Colombia, Peru, Chile, Argentina, Uruguay, Brazil, and Venezuela. The survey revealed 590 cases diagnosed with a significant pathology, injury or malformation on a total of 7635 specimens of 12 odontocete species examined or observed in 1984-2007. Tattoo skin disease (TSD), lobomycosis-like disease (LLD) and cutaneous diseases of unknown aetiology seem to be emerging in several populations. TSD was confirmed in eight species from the SE Pacific and SW Atlantic. LLD affected only inshore Tursiops truncatus but was found in four tropical countries, namely Colombia, Ecuador, Peru and Brazil. Lobomycosis was confirmed by histology in one male from the Tramandaí estuary, southern Brazil. All LLD-affected specimens were encountered in the vicinity of major ports and cities and a possible association with chemical or organic water pollution is suspected. Whitish velvety cutaneous marks associated with scars occurred in inshore T. truncatus, Sotalia guianensis and Pseudorca crassidens. Large, rounded lesions were seen in a Cephalorhynchus eutropia calf and a C. commersonii. Cutaneous wounds and scars as well as body traumata possibly related to net entanglements and boat collisions were observed in 73 delphinids and Phocoena spinipinnis. Traumatic injuries resulted in the partial or complete amputation and other disfiguring scars of appendages in 17 cases. Fractures of the skull, ribs and vertebrae thought to be caused by fisheries-related interactions or boat collisions were seen in single individuals of Delphinus capensis, Lagenorhynchus obscurus, T. truncatus, S. guianensis and Ziphius cavirostris. Prevalence of osteopathology in small cetaceans from Peru, Brazil and Venezuela ranged widely, from 5.4% to 69.1%. In four species from Peru, lytic cranial lesions were the most frequently observed disease (5.4%-42.9%), followed by hyperostosis and ankylosing spondylitis in offshore (31%, n=42) and inshore (15.4%, n=26) T. truncatus. Fractures and other bone traumata were present in 47.2% of 53 axial skeletons of S. guianensis from the northern Rio de Janeiro state (Brazil) in 1987-1998. A high prevalence (48.4%, n=31) of, apparently congenital, malformations of cervical vertebrae, observed in a 2001-2006 sample, may be explained by a hypothetical genetic bottleneck in this population. Malformations with deficient ossification would clearly increase susceptibility for fractures. This study demonstrates the utility of a continent-wide analysis to discern epizootiological trends more readily than any local study could provide. Secondly, it underscores the need for focussed research on the effects of human activities on the spread of diseases in cetaceans, particularly in near-shore populations that utilize highly degraded coastal habitats

Variation in δ13C and δ15N values of mothers and their calves across southern right whale nursery grounds: the effects of nutritional stress?

Southern right whales (SRW) are capital breeders that use stored energy reserves to sustain themselves and their calves on nursery areas. With successful calving events declining in some SRW populations, it has been hypothesized that nutritional stress in adult females causes reproductive failure or death of calves shortly after birth. Here we compared offsets in carbon and nitrogen isotope values of mothers and their offspring (∆13 Ccalf-cow and ∆15 Ncalf-cow) among three SRW populations. SRW from Aotearoa New Zealand, with high population growth rates and body conditions scores, have negative ∆13Ccalf-cow suggesting calves are utilizing 13 C-depleted lipid carbon in milk to fuel the synthesis of nonessential amino acids used to build new tissues and rapidly grow. In contrast, a significantly positive ∆13 Ccalf-cow offset previously reported for SRW from Argentina during a mass die-off event was hypothesized to be due to calves consuming milk with low lipid content. Patterns in ∆15 Ncalf-cow were more difficult to interpret and highlight the complexity in nitrogen transfer between mother and offspring. When combined with similar data collected from Brazil and during a low mortality year in Argentina, we hypothesize this approach provides a way to retrospectively compare nutritional condition of breeding adult female SRW across nursery areas

Crescimento e desenvolvimento de boto-cinza (Sotalia guianensis) do litoral do Espírito Santo

Estudou-se o desenvolvimento do boto-cinza (Sotalia guianensis) do litoral do Espírito Santo e verificou-se se a análise das radiografias da aleta peitoral pode ser utilizada para tal. Trinta e sete botos passaram pela determinação do comprimento total (CT), análise do grau de fusionamento das vértebras e radiografia das aletas peitorais. O CT ao nascimento foi de 103,3cm e o de animais maduros fisicamente 187,5cm. Observou-se correlação entre o CT, as epífises distais do rádio e da ulna e correlação entre o grau de fusionamento vertebral e a epífise distal do rádio. Concluiu-se que a análise radiográfica das aletas peitorais é uma boa maneira de avaliar o grau de maturação física do boto

Seasonal and daily patterns of group size, cohesion and activity of the estuarine dolphin, Sotalia guianensis (P.J. van Bénéden) (Cetacea, Delphinidae), in southern Brazil Padrões sazonais e diários do tamanho de grupo, coesão e atividade do boto-cinza, Sotalia guianensis (P.J. van Bénéden) (Cetacea, Delphinidae), no sul do Brasil

The resident population of estuarine dolphin, Sotalia guianensis (P.J. van Bénéden, 1864), in Norte Bay, Santa Catarina, southern Brazil, was studied from 2000 to 2003. Systematic one-day cruises were undertaken aboard a 5 m sail boat equipped with an outboard motor. Applying the focal-group method, information such as geographical position, predominant behavioural patterns, group size, cohesion index and the presence of calves, were registered at every five-minute interval, totalling 198 hours of direct observation of the dolphins. The estuarine dolphin used preferential areas for each behavioural pattern. The mean group size was approximately 29 individuals, and the presence of calves occurred throughout the entire year, but with a significant increase in the warm seasons. The frequency of behavioural patterns and group size varied according to season and time of day, and were strongly associated. The frequency of moving behaviours increased in the cold seasons and along the day. The seasonal variation in the moving behaviours suggest the requirement of a larger area in the cold seasons, probably related to seasonal fluctuations in the abundance of dominant prey items. Higher group sizes were observed while dolphins were foraging. The cohesion index also varied according to the behaviour. Our results showed that group organization and behavioural patterns of this estuarine dolphin population are probably linked to daily and seasonal environment cycles, and also possibly to the condition of being at the furthest southern limit of distribution of the species.<br>A população residente de boto-cinza, Sotalia guianensis (P.J. van Bénéden, 1864), da Baía Norte, Santa Catarina, sul do Brasil, foi estudada de 2000 a 2003. Foram realizados cruzeiros sistemáticos de um dia, a bordo de um veleiro de 5 m equipado com motor de popa. Utilizando o método de grupo-focal, informações como posição geográfica, padrão comportamental predominante, tamanho de grupo, índice de coesão e presença de filhotes, foram registradas a cada intervalo de cinco minutos, totalizando 198 horas de observação direta dos botos. O boto-cinza utilizou áreas preferenciais para cada padrão comportamental. O tamanho médio de grupo foi aproximadamente de 29 indivíduos, e a presença de filhotes ocorreu ao longo de todo o ano, porém com aumento significante nas estações quentes. A freqüência dos padrões comportamentais e o tamanho de grupo apresentaram forte correlação, e variaram em relação à estação do ano e hora do dia. Os comportamentos de movimento foram mais freqüentes nas estações frias e ao longo do dia. A variação sazonal destes comportamentos sugere o requerimento de maiores áreas nas estações frias, provavelmente relacionado com as flutuações sazonais de abundância e dominância de presas. Os maiores tamanhos de grupo ocorreram em comportamentos de forrageio. O índice de coesão também variou com o comportamento. Nossos resultados demonstram que a organização de grupo e os padrões comportamentais desta população de boto-cinza são provavelmente influenciados por ciclos ambientais diários e sazonais, e pela condição de limite sul de distribuição para a espécie