Monitoreo Participativo De La Caza De Quelonios (Podocnemididae) Por Ribereños En El Bajo Río Purús Y Protección De Lugares De Desova En La Rds Piagaçu-Purus, Brasil.

 Between September 2011 and April 2012, we recorded with local people participation, information about chelonians’ nesting sites and the species hunted by local people for subsistence, in three distinct sectors of Sustainable Development Reserve Piagaçu-Purus (RDS-PP). We documented 120 hunted chelonians (26 Podocnemis expansa and 94 P. unifilis) in 20 water bodies at use areas these riverine communities.Entre septiembre de 2011 y abril de 2012, se registraron informaciones participativas sobre las áreas de anidación y de las especies de quelonios cazados para el consumo por ribereños comunitarios de tres sectores de La Reserva de Desarrollo Sostenible Piagaçu-Purus (RDS-PP). Fueron registrados 120 quelonios capturados (26 Podocnemis expansa y 94 P. unifilis) en 20 cuerpos hídricos de uso de las comunidades

Body size is more important than diet in determining stable-isotope estimates of trophic position in crocodilians

The trophic position of a top predator, synonymous with food-chain length, is one of the most fundamental attributes of ecosystems. Stable isotope ratios of nitrogen (δ 15N) have been used to estimate trophic position of organisms due to the predictable enrichment of 15N in consumer tissues relative to their diet. Previous studies in crocodilians have found upward ontogenetic shifts in their 'trophic position'. However, such increases are not expected from what is known about crocodilian diets because ontogenetic shifts in diet relate to taxonomic categories of prey rather than shifts to prey from higher trophic levels. When we analysed dietary information from the literature on the four Amazonian crocodilians, ontogenetic shifts in dietary-based trophic position (TPdiet) were minimal, and differed from those estimated using δ 15N data (TPSIA). Thus, ontogenetic shifts in TPSIA may result not only from dietary assimilation but also from trophic discrimination factors (TDF or Δ 15N) associated with body size. Using a unique TDF value to estimate trophic position of crocodilians of all sizes might obscure conclusions about ontogenetic shifts in trophic position. Our findings may change the way that researchers estimate trophic position of organisms that show orders of magnitude differences in size across their life span. © 2018 The Author(s)

Conservation and management implications of nest-site selection of the sympatric crocodilians Melanosuchus niger and Caiman crocodilus in Central Amazonia, Brazil

Management of crocodilians is often based on source-sink dynamics, protecting breeding habitat and concentrating hunting in other areas. Nest distributions shed light on habitat use by breeding populations, which might be used as a basis for monitoring and management. The heterogeneous spatial distribution of Melanosuchus niger and Caiman crocodilus in Amazonia has been suggested to reflect past hunting pressure, often underestimating the natural ecological peculiarities of these species. Ground nest surveys combined with satellite imagery allowed us to evaluate whether nest-site use by M. niger and C. crocodilus reflects environmental constraints or is a result of hunting pressure. Our results indicate that there is little evidence that hunting pressure shapes nest-site use of these species in our study areas. M. niger nests mainly on the shores of stable, temporally impounded floodplain lakes isolated from the early stages of the annual rising water of main rivers. This behavior facilitates the identification of suitable nesting sites using moderate-resolution remote-sensing tools and should guide monitoring efforts and the protection of these areas. In contrast, C. crocodilus is a generalist species, able to nest hundreds of meters inside the forest far from permanent water. This makes the occurrence and distribution of nesting-sites unpredictable using Landsat images. Although nests of this species can be found around lakes where nests of M. niger also occur, the protection of these sites might help to preserve only a small portion of C. crocodilus nesting females. Thus, conservation strategies for C. crocodilus should probably be based on different approaches. © 2010 Elsevier Ltd

Riscos na qualidade sanitária da carne de jacaré da Amazônia Central

Determining caiman meat quality is a major problem when establishing the production chain of wild populations. In Brazil, there are no protocols for this type of meat. The slaughter and processing were performed using a simplified, traditional floating raft system and a water treatment system that used both filtration and chemicals. The animals were caught using a hook, harpoon, resting pole, and cable snare. The wild caimans of two species (Melanosuchus niger and Caiman crocodilus) were captured in the region of the Piagaçu-Purus Sustainable Development Reserve in Central Amazon during three harvesting events. After each event, we progressively improved the meat-processing protocol. Microbiological testing of the meat was performed as described in norms and Brazilian legislation for fish meat. As a result, we achieved improvements in the sanitary quality of the meat of the killed animals for 57%, 76.5% and 100% of the samples obtained during the first, second, and third harvesting events, respectively. There were significant differences in the microbiological quality of the meat, with a reduction in the disapproval of the samples. The process of capturing animals, the cable snare, and the restraining pole were the factors that least affected the quality of the meat; in addition, animals between 81 and 100 cm of CRC had a lower risk of microbiological contamination. We can conclude that health surveillance activities, such as hand hygiene when handling meat, improvements in water quality, selection of animals of the most appropriate size for slaughter, and capture by less invasive methods can reduce the potential for microbiological contamination of the meat contribute to decrease the potential for microbiological contamination of meat.A determinação da qualidade sanitária da carne de jacaré é um dos principais problemas no estabelecimento da cadeia produtiva deste animal, pois não existem protocolos no Brasil para esse tipo de carne. O abate e processamento da carne foram realizados em sistema simplificado e artesanal em balsa flutuante, com sistema de tratamento de água por filtração e produtos químicos. Os animais foram capturados por anzol, arpão, cambão e laço. Foram capturados animais de vida silvestre na região da Reserva de Desenvolvimento Sustentável Piagaçu-Purus, na Amazônia Central, das espécies Melanosuchus niger e Caiman crocodilos, em três eventos de abate, com melhoria progressiva no protocolo de beneficiamento da carne. Foram feitas análises microbiológicas da carne, conforme descrito em normas e legislações brasileiras para a carne de pescado. Como resultados da pesquisa obtivemos melhorias na qualidade microbiológica da carne dos animais abatidos, conforme as medidas de vigilância sanitária que foram adotadas, passando de 57% de amostras aprovadas no 1º lote de abate para 76,5% no 2º lote e, no final, para 100% no 3º lote. Ocorreram diferenças significativas no comprometimento da qualidade sanitária da carne, com diminuição das reprovações das amostras. Os processos de captura dos animais, laço e cambão foram os que menos comprometeram a qualidade da carne, e animais com tamanho na faixa de 81 a 100 cm de CRC foram os que apresentaram menor risco de contaminação microbiológica. Podemos concluir que ações de vigilância sanitária como: higienização das mãos durante a manipulação da carne, melhorias na qualidade da água, abate de animais no tamanho mais adequado e captura por métodos menos invasivos contribuem para diminuição dos riscos potenciais de contaminação microbiológica da carne

The metabolic cost of nesting: body condition and blood parameters of Caiman crocodilus and Melanosuchus niger in Central Amazonia

Although nesting ecology is well studied in several crocodilian species, it is not known how nest attendance influences physiology and body condition of nesting females. In this study, we describe body condition and serum biochemical values of nesting female, non-nesting female and male spectacled caiman (Caiman crocodilus) and black caiman (Melanosuchus niger) in two areas of Central Amazonia. We also evaluated the effect of nest age and nest distance to water on body condition and blood parameters of nesting females. Body condition and plasmatic concentrations of glucose, triglycerides, lactate and uric acid of nesting females were significantly different from those of non-nesting females and males in C. crocodilus, but not in M. niger. Our study also demonstrated that nest age and distance to water had a negative effect on female body condition in C. crocodilus, but not in M. niger. Female C. crocodilus attending older nests or nests built further away from permanent water bodies tended to have lower body condition. Our results demonstrate that the nesting strategy of C. crocodilus has a metabolic cost associated with nest attendance for nesting females, which appear to depend on accumulated energetic reserves during nest attendance. In contrast, nest attendance had little effect on the physiology of female M. niger. © 2017, The Author(s)

Evidence of cryptic lineages within a small South American crocodilian: the Schneider’s dwarf caiman Paleosuchus trigonatus (Alligatoridae: Caimaninae)

Schneider’s dwarf caiman Paleosuchus trigonatus is one of the smallest living crocodilians. Due to its broad distribution, cryptic behavior, and small home range, the species is well suited for the study of phylogeographic patterns on a continental scale. Additionally, this species is under threat due to habitat loss, trade and harvest, but is considered at low conservation risk by the IUCN. In the present study we test the hypothesis that P. trigonatus is comprised of geographically structured lineages. Phylogenetic reconstructions of the mitochondrial cytochrome b gene and single locus species discovery methods revealed the existence of two well-supported lineages within P. trigonatus—an Amazonian and Guianan lineage. Fossil calibrated divergence of these lineages was estimated to have occurred in the Late Miocene (7.5 Ma). The hypothesis that the Atlantic coast drainages might have been colonized from the southeast or central Amazon is supported by demographic metrics and relatively low genetic diversity of the Coastal and upper Branco populations when compared to the Amazon basin populations. The Amazon basin lineage is structured along an east-west gradient, with a sharp transition in haplotype frequencies to the east and west of the Negro and Madeira rivers. These lineages are already under anthropogenic threat and, therefore, are conservation dependent. Recognition of these lineages will foster discussion of conservation future of P. trigonatus and these lineages

Data from: Genetic evidence for polygamy as a mating strategy in Caiman crocodilus

The mating system of the spectacled caiman (Caiman crocodilus) was investigated in the Piagaçu-Purus Sustainable Development Reserve, Amazonas, Brazil. We used six polymorphic microsatellite loci to genotype 15 females and 174 hatchlings representing 20 nests sampled over four consecutive reproductive seasons (2007 to 2010). Paternity was determined by two methods: simple counts, and statistical analysis using Gerud 2.0. Results were congruent between the two approaches, and the null hypothesis of single paternity was rejected in 19 of the 20 nests analyzed, thereby demonstrating that C. crocodilus females are polyandrous and that the breeding system of the species can be characterized as polygamous. The data suggest that one to four fathers were responsible for the paternity of the offspring, and that the males contributed differently (9%-100%) to each of the 20 nests. A total of 53 males copulated with the 20 females mothering the nests. This is the first study on the mating system of C. crocodilus and the frequency of multiple paternity is among the highest values (95%) reported thus far for crocodilians

Feeding behavior of two sympatric caiman species, Melanosuchus niger and Caiman crocodilus, in the Brazilian Amazon

We studied the feeding behaviors of two sympatric species of caimans (Melanosuchus niger and Caiman crocodilus) during the dry season in the Mamirauá Sustainable Development Reserve, Amazonas State, Brazil. Observations were made in 50 X 13 m plots located along the land-water interface. We investigated the influence of interspecific density and the effects of temperature and water depth on the feeding behaviors of both species. We identified three principal categories of feeding behavior: trapping (with the body perpendicular to the shore, the caiman captures prey swimming close to the shore), active search (with the head under the water, the caiman searches for benthic prey), and jumping (leaping partially out of the water and capturing fish or other under water invertebrates prey). Using multiple linear regression, we found that water temperature had a negative effect on trapping by M. niger; and water depth did not affect feeding behaviors in either species. Density of M. niger did not affect either the density or the frequency of feeding by C. crocodilus. Results suggest that environmental factors have little influence on the feeding behaviors of the caimans we studied, and there is probably little interspecific competition for food during the dry season. Copyright 2008 Society for the Study of Amphibians and Reptiles