RESUMENEl presente estudio determinó, mediante exámenes coprológicos, la presencia de parásitos gastrointestinales en primates no humanos en cautiverio del Zoológico Parque Natural de Pucallpa, ubicado en el departamento de Ucayali -Perú. Se recolectaron 72 muestras fecales colectivas de 58 primates de las especies Cebus apella (machín negro),
ABSTRACTThe present study detected by stool examinations the presence of gastrointestinal parasites in nonhuman primates reared in captivity at the Pucallpa Natural Zoological Park, located in the department of Ucayali -Peru. A total of 72 collective fecal samples were collected from 58 individuals from species Cebus apella (brown capuchins), Saguinus fuscicollis weddelli (saddleback tamarins), Cebus albifrons (white-fronted capuchins), Lagothrix lagotricha (woolly monkey), Ateles paniscus chamek (spider monkey), Saimiri
Stable isotope analysis of tissues with different turnover rates allows for a broader temporal view of a species’ feeding habits. Epidermal mucus is a rapid to medium turnover ‘tissue’ in teleost fish, but its use in elasmobranch dietary studies is unknown. In the present study, we conducted stable isotope analysis on mucus and muscle from the giant manta ray Manta birostris. Mucus δ13C values were depleted and closer to surface zooplankton δ13C values compared with muscle, whereas there was no significant difference in δ15N values between these two tissue types. Using diet tissue discrimination factors from the literature, there was no significant difference in the expected prey profile between muscle and epidermal mucus. However, a broader range in δ13C values of expected prey was shown for mucus compared with muscle. The results suggest that if M. birostris mucus is indicative of recent dietary intake, resource use during aggregative behaviour off Ecuador is broader, but with no obvious resource switching. The present study is the first example of using bulk stable isotope analysis to evaluate mucus to investigate feeding ecology in elasmobranchs. However, the time course for the change in mucus isotope signature still needs to be determined through controlled feeding studies in an aquarium setting.
Traditionally, large planktivorous elasmobranchs have been thought to predominantly feed on surface zooplankton during daytime hours. However, the recent application of molecular methods to examine long-term assimilated diets, has revealed that these species likely gain the majority from deeper or demersal sources. Signature fatty acid analysis (FA) of muscle tissue was used to examine the assimilated diet of the giant manta ray Mobula birostris, and then compared with surface zooplankton that was collected during feeding and non-feeding events at two aggregation sites off mainland Ecuador. The FA profiles of M. birostris and surface zooplankton were markedly different apart from similar proportions of arachidonic acid, which suggests daytime surface zooplankton may comprise a small amount of dietary intake for M. birostris. The FA profile of M. birostris muscle was found to be depleted in polyunsaturated fatty acids, and instead comprised high proportions of 18:1ω9 isomers. While 18:1ω9 isomers are not explicitly considered dietary FAs, they are commonly found in high proportions in deep-sea organisms, including elasmobranch species. Overall, the FA profile of M. birostris suggests a diet that is mesopelagic in origin, but many mesopelagic zooplankton species also vertically migrate, staying deep during the day and moving to shallower waters at night. Here, signature FA analysis is unable to resolve the depth at which these putative dietary items were consumed and how availability of this prey may drive distribution and movements of this large filter-feeder.
Information on the life history and demographics of oceanic manta rays Mobula birostris remains scarce. Using photo-ID data, we describe the demographic structure, population size, and possible environmental drivers of the seasonal occurrence of M. birostris at Isla de la Plata and Bajo Copé, Ecuador. We identified a total of 2803 individuals from 3322 encounters over a period of 14 yr (2005-2018). The population sampled at these sites was significantly biased towards males (sex ratio 1F:1.67M) and only 12.9% of individuals were resighted. We used mark-resight models to estimate demographic parameters of the population, including superpopulation size, survival probability, entry/recruitment probability, and detection probability. We also evaluated how these parameters were related to environmental predictors, such as El Niño-Southern Oscillation (ENSO), sea surface temperature (SST), and chlorophyll a (chl a). Mark-resight analyses indicated that SST, chl a, time, and sex, but not ENSO, were important predictors of estimated population parameters. Entry probability peaked in 2012, which coincided with the lowest SST and highest chl a concentrations. The best-fit mark-resight model estimated a superpopulation size of 22316 individuals, with annual estimated abundances of 949-7650 females and 5226-9340 males. Localised sampling of this highly mobile species limits the interpretations of mark-resight analyses, but provides lower bounds for total abundance that indicate the population of M. birostris in coastal Ecuador and Peru is likely the largest in the world.
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