Factors Affecting the Number of Caimans Seen during Spotlight Surveys in the Mamirauá Reserve, Brazilian Amazonia

Silveira, Ronis Da; Magnusson, William E.; Thorbjarnarson, John B.

doi:10.1643/ce-06-035

Cited by 29 publications

(23 citation statements)

References 6 publications

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“…M. niger can reach [4.5 m TL (Da Silveira et al 2008), whereas our specimens ranged between 75 and 190.9 cm (mean 104.5). C. c. crocodilus can reach approximately 2 m in total length (Da Silveira et al 2008), and our specimens ranged from 62 to 98 cm (mean 75.4).…”

Section: Hg Concentration Versus Caiman Size and Sexmentioning

confidence: 76%

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Mercury Concentration in the Spectacled Caiman and Black Caiman (Alligatoridae) of the Amazon: Implications for Human Health

Schneider

Peleja

Junior

et al. 2012

Arch Environ Contam Toxicol

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Mercury (Hg) concentrations in the Amazon are generally high, but no studies have been published on Hg concentrations in caimans (Alligatoridae) from the region. Aiming for sizes representative of caimans traded for food in the Amazon, we measured Hg concentration in tail muscle of spectacled caiman (Caiman crocodilus crocodilus) and black caiman (Melanosuchus niger) from the Purus River basin. The information on Hg concentration in caimans from this area is important because of the potential health risk to humans and other animals that eat them as well as the potential use of these top-level predators as bioindicators. There were no significant interspecific or sex differences in Hg concentrations. The mean Hg concentration was 291.2 μg/kg in C. c. crocodilus and 193.9 μg/kg in M. niger. A significant positive correlation between Hg concentration and size was found for M. niger (p = 0.005) but not for C. c. crocodilus. Our Hg sample from M. niger corresponded to the size of M. niger collected for commercial trade, but our Hg sample from C. c. crocodilus turned out to be significantly smaller than the trade samples (p = 0.004), but this difference is not pertinent in the absence of a correlation between size and Hg concentration for this species. Although there are no standards for reptile meat, both species had mean Hg concentrations lower than the maximum allowable level of 500 μg/kg Hg recommended by the World Health Organization and by the Brazilian Health Ministry for fish. However, by calculating daily consumptions limits and number of meals per month that can be safely consumed, we found that consumers who eat caimans frequently may be at risk for Hg-related health problems.

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Section: Hg Concentration Versus Caiman Size and Sexmentioning

confidence: 76%

“…The black caiman (Melanosuchus niger) can reach [4.5 m in total length (TL), and the spectacled caiman (Caiman crocodilus crocodilus) can reach approximately 2 m TL. The largest populations of both species occur in the va´rzea-flooded habitats formed by Andean rivers, such as the Solimões and Purus rivers (Da Silveira et al 2008).…”

mentioning

confidence: 99%

Mercury Concentration in the Spectacled Caiman and Black Caiman (Alligatoridae) of the Amazon: Implications for Human Health

Schneider

Peleja

Junior

et al. 2012

Arch Environ Contam Toxicol

Self Cite

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“…Both methods have in common the variation in the number of individuals observed according to water level and lunar illumination. The method is considered relatively accurate for crocodilians, especially when these variables are accounted for (Da Silveira et al, 2008). However, the spotlighting method needs to be standardised for monitoring paca populations near water bodies and, in this case, hunters´ knowledge must underpin standardisation efforts.…”

Section: Discussionmentioning

confidence: 99%

Subsistence hunting of Cuniculus pacain the middle of the Solimões River, Amazonas, Brazil

2014

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Ungulates, large primates and caviomorfs are cited by Amazonian hunters as preferred species. In this research, paca (Cuniculus paca) hunting was investigated in relation to water levels and the lunar cycle. In eight years of monitoring in the Amanã Sustainable Development Reserve, the killing of 625 pacas was registered in five monitored communities. Paca hunting took place mainly at night and the most commonly used method is "spotlighting". A positive correlation between the number of pacas killed and water level (r s =0.890; p<0.0001) was found. At least 37% of the pacas were hunted when moon illumination level was less than 10%, before moonrise or after moonset. In the Boa Esperança community, capture of paca tended to decrease on nights with high moon illumination (r s = -0.663; p=0.067). At the same time, an expressive catch-per-unity-effort decrease was also observed in this community (r 2 = -0.881; p<0.001), allowing us to predict unsustainable hunting levels for the next decade. The stock of animals in these areas could be continuously replaced if surrounding areas consisted of continuous forests. However, continuous hunting and deforestation force local hunters to travel longer distances to kill prey such as pacas. The confirmation of the relation between paca habits and lunar illumination and water level, a pattern described by local hunters, demonstrates the potential value of participatory research and the possibility of integrating traditional knowledge into scientific knowledge.Keywords: abundance, catch-per-unity-effort, Cuniculus paca, hunting, Amazon. Caça de subsistência de Cuniculus paca no Médio Solimões, Amazonas, Brasil ResumoUngulados, primatas de grande porte e caviomorfos são citados por caçadores amazônicos como espécies preferenciais. Neste trabalho, a caça de paca (Cuniculus paca) foi investigada em relação ao nível d'água e ao ciclo lunar. O abate de 625 pacas foi registrado em oito anos de monitoramento em cinco comunidades da Reserva de Desenvolvimento Sustentável Amanã. A caça de paca ocorre principalmente à noite e o método mais utilizado é a "focagem". Encontrou-se uma correlação positiva entre o número de pacas abatidas e o nível d'água (r s =0.890; p<0.0001). Pelo menos 37% dos indivíduos foram abatidos quando o nível de iluminação lunar era menor do que 10%, antes do nascer da lua ou após seu ocaso. Na comunidade da Boa Esperança, a captura de paca tendeu ao decrescimento em noites com altos níveis de iluminação lunar (r s =-0.663; p=0.067). Ao mesmo tempo, uma expressiva redução da captura por unidade de esforço foi observada nessa comunidade (r 2 =-0.881; p<0.001), permitindo-nos prever níveis de caça insustentáveis para a próxima década. Frente a extensas áreas contínuas de floresta, o estoque de animais nas áreas de caça poderia ser continuamente substituído, mas os efeitos combinados de caça constante e desmatamento forçam caçadores locais a se locomoverem por longas distâncias para abater presas como as pacas. A confirmação dos padrões descritos por moradores l...

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“…The majority of the studies on Amazonian caiman biology and ecology were carried out in Anavilhanas National Park [4,9], Mamirauá SDR [4,8,[10][11][12], Piagaçu-Purus SDR [5][6][12][13][14], Jaú National Park [15] and Abufari Biological Reserve [16]. Highly qualified scientists or graduate students undertook these studies with participation from local inhabitants, primarily as guides or field assistants.…”

Section: Scientific Researchmentioning

confidence: 99%

Local Community Involvement as a Basis for Sustainable Crocodilian Management in Protected Areas of Central Amazonia: Problem or Solution?

Marioni

Botero‐Arias

Fonseca-Junior

2013

Tropical Conservation Science

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Amazon floodplains have a long history of exploitation of crocodilians, particularly of large species such as the black caiman (Melanosuchus niger) and spectacled caiman (Caiman crocodilus). Historically, legal but uncontrolled trade resulted in a drastic reduction of wild populations of both species, which eventually led to the collapse of the commercial trade. In 1967, prohibition of commercial use of wild fauna through changes in Brazilian and international laws allowed caiman populations to slowly recover across much of their original range. Several studies on caiman populations greatly improved knowledge about the species, offering scientific bases for crocodilian management in the wild. Although protective legislation should only be altered using extreme caution, the creation of Sustainable Development Reserves (SDR) at the end of last century made it possible to manage wildlife for commercial purposes, albeit under strict population monitoring regimes. This category of protected area was established to improve welfare of local communities and strengthen their participation in conservation. Along with involvement in caiman monitoring programs, the engagement of local hunters and buyers is essential for participatory management plans. Even with development of SDRs, monitoring of crocodilian populations is still restricted to a few State Reserves, and traditional knowledge of stakeholders has been insufficiently incorporated into management and monitoring activities. We believe that stronger participation of local actors can help to improve the experimental harvesting initiatives that have been carried out thus far by local authorities. Community-based monitoring programs, which reflect local reality, are being developed in a simple and costeffective way. Key word: Amazon, crocodilians, participatory monitoring, local community Resumo A Amazônia possui um histórico de exploração de crocodilianos, principalmente as espécies jacaré-açu (Melanosuchus niger) e jacaretinga (Caiman crocodilus).No passado a caça legal e descontrolada levou a uma drástica diminuição das populações silvestres ao longo da distribuição natural das espécies, resultando em uma extinção comercial. Graças à proibição decidida pela legislação brasileira e internacional do uso e comércio da fauna, nas ultimas três décadas as populações de jacarés estão se recuperando lentamente em muitas localidades. A criação de Unidades de Conservação da categoria Reserva de Desenvolvimento Sustentável e pesquisas científicas permitiram um melhor conhecimento da biologia e ecologia dos jacarés amazônicos e introduziram a possibilidade do manejo de fauna na região. A falta de réplicas nestas pesquisas e seus altos custos ainda limitam o conhecimento sobre o real potencial de exploração comercial de maneira sustentável. O conceito de manejar a fauna é novo para a maioria das comunidades ribeirinhas. O envolvimento de caçadores, associações locais, lideranças e comerciantes é fundamental para elaborar planos de manejo participativos. O monitoramento d...

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Factors Affecting the Number of Caimans Seen during Spotlight Surveys in the Mamirauá Reserve, Brazilian Amazonia

Cited by 29 publications

References 6 publications

Mercury Concentration in the Spectacled Caiman and Black Caiman (Alligatoridae) of the Amazon: Implications for Human Health

Mercury Concentration in the Spectacled Caiman and Black Caiman (Alligatoridae) of the Amazon: Implications for Human Health

Subsistence hunting of Cuniculus pacain the middle of the Solimões River, Amazonas, Brazil

Local Community Involvement as a Basis for Sustainable Crocodilian Management in Protected Areas of Central Amazonia: Problem or Solution?

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