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We quantified changes in body mass, forearm length, and the total length of the epiphyseal gap of the fourth metacarpal-phalangeal joint of the ashy leaf-nosed bat (Hipposideros cineraceus) based on mark-recapture data obtained in Fangkong Cave in Hekou, Yunnan Province, China. We used these data to develop empirical growth curves, to derive growth rates, to establish age-predictive equations, and to compare growth parameters based on three nonlinear growth models. Forearm length and body mass of pups followed a linear pattern of growth until day 17, with mean growth rates of 0.81 mm/day and 0.09 g/day, respectively and thereafter their growth rates increased more slowly. The length of the epiphyseal gap initially increased linearly up to day 13 and then decreased linearly at a mean rate of 0.07 mm/day until day 37. An equation for estimating age based on forearm length was valid when this dimension was ≤ 27.6 mm, whereas the equation based on the length of the epiphyseal gap was valid for forearm lengths ≥ 24.3 mm. Together, these two equations permit estimation of the age H. cineraceus pups between 1 and 37 days. Of the three nonlinear growth models (logistic, Gompertz, and von Bertalanffy), the logistic equation provided the best fit to the empirical curves for body mass and forearm length.
This study investigated the factors (i.e., season, locality, sampling year, total length and maturity stage of the hosts) that might influence the structure of parasite populations and communities in the clingfish Gobiesox marmoratus. The parasite community was described and analyzed using numerical descriptors, such as prevalence, intensity and species richness, between factors previously mentioned. A total of 260 clingfish were collected from 2 localities of central Chile, four seasons and during 3 year cycles (from July 2006 to July 2009). In the whole clingfish sample, 668 parasites were found, which belonged to 14 parasite taxa; 9 of them were new records in G. marmoratus. Parasite infracommunity richness ranged 0–3 species, although 1 trematode species, Helicometrina nimia, represented 80% of all parasites collected and was the most abundant and prevalent parasite species. The average of parasite abundance and intensity (± SD) was 2.5 ± 8.2 and 7.5 ± 12.7, respectively. Generalized linear model showed that parasite communities were influenced by season, locality, sampling year, and maturity stage when considering the abundance and intensity of parasites. For the parasite richness, only the locality and maturity of fish was determinant for explaining the differences. The populations and communities of the parasite variations were variable due to differences in fish body length because prevalence, abundance and intensity of parasites significantly correlated with the fish body length. Concordantly, maturity fish were longer than immature fish. Thus, clingfish from El Tabo were longest and mature, which harbored higher parasite richness than those fish from Las Cruces.
In this study, the total mercury concentration was determined in the muscles, liver and gills of six fish species (rainbow trout Oncorhynchus mykiss Walb., carp Cyprinus carpio L., bream Abramis brama L., perch Perca fluviatilis L., ide Leuciscus idus L. and flounder Platichthys flesus L.). The fish were acquired from October to November 2012. Mercury was analyzed by atomic absorption spectrometry using thermal decomposition, compounds of mercury and amalgamation. The mercury content in fish organs reached 0.006-0.168 (in mg kgˉ¹ wet weight) in muscles, 0.001-0.027 in gills and 0.003-0.045 in the liver. The muscles of perch and ide had significantly more Hg compared to the other fish’s muscles (P≤0.05). The liver and gills of perch, ide and flounder contained more Hg than the same tissues of the other fish (P≤0.05). Generally, the highest Hg content was determined in muscles (except rainbow trout) (P≤0.05), whereas the lowest Hg content was found in gills (except perch) (P≤0.05). The content of Hg in gills of perch did not differ from the one in the liver (P>0.05). There was a positive correlation between the weight or length of a fish and the Hg concentration in its tissues, except for the length and Hg in the gills of carp. However, a statistically significant positive correlation between the body weight and the Hg levels in fish appeared only in the case of the organs of ide (P≤0.004) and muscles of carp (P≤0.038). The correlation between the factor condition and the content of Hg, albeit positive (0.106 < r < 0.811) except for the organs of flounder, was not statistically significant (P>0.05).
Carp were cultivated (from day 3 to 30 after hatching) in water with a nitrite concentration of 7 mg NO₂-N dm³. The results of histological studies confirmed pathological changes in the throat, gills, heart, blood, swim bladder, liver and kidneys. These changes mainly had an adverse impact on respiration and growth. The total length and weight of fish from water with nitrites was lower by 30 and 75%, respectively, and their survival rate was 62% (97% in the control group).
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