Variation In Body Condition Research Articles

The helminth community of a population of Rattus norvegicus from an urban Brazilian slum and the threat of zoonotic diseases.

Urban slums provide suitable conditions for infestation by rats, which harbour and shed a wide diversity of zoonotic pathogens including helminths. We aimed to identify risk factors associated with the probability and intensity of infection of helminths of the digestive tract in an urban slum population of Rattus norvegicus. Among 299 rats, eleven species/groups of helminths were identified, of which Strongyloides sp., Nippostrongylus brasiliensis and, the human pathogen, Angiostrongylus cantonensis were the most frequent (97, 41 and 39%, respectively). Sex interactions highlighted behavioural differences between males and females, as eg males were more likely to be infected with N. brasiliensis where rat signs were present, and males presented more intense infections of Strongyloides sp. Moreover, rats in poor body condition had higher intensities of N. brasiliensis. We describe a high global richness of parasites in R. norvegicus, including five species known to cause disease in humans. Among these, A. cantonensis was found in high prevalence and it was ubiquitous in the study area - knowledge which is of public health importance. A variety of environmental, demographic and body condition variables were associated with helminth species infection of rats, suggesting a comparable variety of risk factors for humans.

Decreasing reservoir water levels improve habitat quality for Asian elephants

Population health and habitat quality are intimately related and seasonal changes in habitat quality are likely to be reflected in the body condition of animals. We studied seasonal variation of body condition in free ranging Asian elephants (Elephas maximus) in Udawalawe National Park, Sri Lanka based on visual scoring of individually identified elephants. We assessed the body condition of 218 adult females and 329 adult males from January 2008 to November 2012 and examined its relation to monthly rainfall and water level of the Udawalawe reservoir. Contrary to expectations, body condition of elephants was higher in the dry season, when primary productivity decreases due to lack of rainfall. However, the body condition showed both a seasonal and inter-annual negative co-relation with reservoir water level. A possible explanation for improved body condition in the dry season is the greater availability of fresh grass due to the emergence of reservoir bed grasslands with the drawdown of water. Our results underscore the importance of water management of large irrigation reservoirs in elephant conservation in Sri Lanka.

Morphometric discrimination of pelagic fish stocks challenged by variation in body condition

Abstract Morphometric characters have traditionally been used to describe the population structure of fishes. Body shape variation, which is often environmentally induced, may provide a good record of short-term population structuring. However, factors unrelated to environmental or genetic influences on body morphology may complicate sampling and the use of morphometric features for stock discrimination. In the present study, we used geometric morphometric variables to compare the European sardine Sardina pilchardus putative stocks of the Aegean and Ionian Seas (eastern Mediterranean). Landmark data of fish collected at seven different sites were subjected to canonical analysis of principal coordinates (CAP). The average body condition of sardines from these sites was strongly and linearly related to corresponding scores along CAP1, the axis exhibiting the highest correlation with the morphometric data cloud. The average scores along CAP2 and CAP3 appeared to be linked to morphological differentiation related to temperature effects and prey availability (mesozooplankton biomass). Despite the primary and confounding effect of body condition, discrimination of different morphotypes corresponding to the Aegean and the Ionian Sea stocks was highly significant with 81% correct reallocations for the respective CAP model.

Reproductive Contributions of Cardinals Are Consistent with a Hypothesis of Relaxed Selection in Urban Landscapes

Human activities are leading to rapid environmental change globally and may affect the eco-evolutionary dynamics of species inhabiting human-dominated landscapes. Theory suggests that increases in environmental heterogeneity should promote variation in reproductive performance among individuals. At the same time, we know that novel environments, such as our urbanizing study system, may represent more benign or predictable environments due to resource subsidies and ecological changes. We tested the hypothesis that reduced environmental heterogeneity and enhanced resource availability in cities relax selective pressures on birds by testing if urban females vary less than rural females in their demographic contributions to local populations. From 2004-2014, we monitored local population densities and annual reproductive output of 470 female Northern Cardinals (Cardinalis cardinalis) breeding at 14 forested sites distributed across a rural-to-urban landscape gradient in Ohio, USA. Reproductive contribution was measured as the difference between individual and site-averaged annual reproductive output across all nesting attempts, divided by the annual density at each site. We show that among-individual variation in reproductive contribution to the next year’s population declined with increasing urbanization, despite similar variability in body condition across the rural-urban gradient. Thus, female cardinals that bred in urban habitats within our study area were more similar in their contribution to the next generation than rural breeders, where a pattern of winners and losers was more evident. Within-individual variation in annual reproductive contribution also declined with increasing urbanization, indicating that performance of females was also more consistent among years in urban than rural landscapes. These findings are consistent with the hypothesis that urbanized environments offer more homogeneous or predictable conditions that may buffer individuals from environmental heterogeneity and relax natural selection.

Body condition, diet and ecosystem function of red deer (Cervus elaphus) in a fenced nature reserve

Body condition, as a sign of animal welfare, is of management concern in rewilding projects where fenced animals are subject to winter starvation, which may conflict with animal welfare legislation. Investigating the relationship between body condition, age, sex, diet quality and diet composition is therefore relevant to increase understanding of herbivores' ecosystem function and to inform management. In this study, we focused on red deer, Cervus elaphus, in a fenced nature reserve in Denmark, where the deer are managed as ecosystem engineers to contribute to biodiversity conservation. We measured body mass and body size of 91 culled red deer, and determined diet composition using DNA metabarcoding and diet quality using fecal nitrogen on 246 fecal samples. We found that body condition was predicted by age and diet composition, but not diet quality. We also found that individuals of different body condition had different diets, i.e., the fecal samples of red deer in poorer body condition contained significantly more Ericaceae sequences than red deer in good body condition. This may imply that certain functions of red deer in ecosystems, such as regeneration of heather by grazing, may depend on variation in body condition within the population. Our findings call for the need to consider the consequences of management practices, including culling or supplemental feeding, on the outcomes of habitat restoration, and more broadly underline the importance of preserving the overall breath of herbivore ecosystem functions for effective biodiversity conservation.

Potentiation of ecological factors on the disruption of thyroid hormones by organo-halogenated contaminants in female polar bears (Ursus maritimus) from the Barents Sea

As apex predators, polar bears (Ursus maritimus) are among the most heavily polluted organisms in the Arctic. In addition to this anthropogenic stressor, climate warming has been shown to negatively affect their body condition, reproductive output and survival. Among potential underlying physiological mechanisms, thyroid hormones (THs), which control thermoregulation, metabolism and reproduction, can be affected by a variety of both natural and anthropogenic factors. While THs have been extensively used as proxies for pollution exposure in mammals, including polar bears, there is a lack of knowledge of their natural variations. In this context, we examined seasonal variations in body condition and circulating TH concentrations in free-ranging female polar bears. Females with variable reproductive status (i.e., solitary, with cubs of the year or with yearlings) were sampled from locations with contrasted sea ice conditions. Furthermore, we studied THs in relation to levels of organo-halogenated contaminants. As predicted, solitary females were in better condition than females caring for offspring, especially in spring. In addition, TH levels were lower in autumn compared to spring, although this seasonal effect was mainly observed in solitary females. Finally, the negative relationships between organochlorine and perfluoroalkyl substances and some THs suggest a possible alteration of homeostasis of THs. Since the latter relationships were only observed during spring, we emphasize the importance of considering the ecological factors when using THs as proxies for pollution exposure. Yet, the combined effects of natural and anthropogenic stressors on THs might impair the ability of polar bears to adapt to ongoing climate changes.

Intraspecific variability in the life histories of endemic coral-reef fishes between photic and mesophotic depths across the Central Pacific Ocean

Mesophotic coral ecosystems (MCEs) represent the lowest depth distribution inhabited by many coral reef-associated organisms. Research on fishes associated with MCEs is sparse, leading to a critical lack of knowledge of how reef fish found at mesophotic depths may vary from their shallow reef conspecifics. We investigated intraspecific variability in body condition and growth of three Hawaiian endemics collected from shallow, photic reefs (5–33 m deep) and MCEs (40–75 m) throughout the Hawaiian Archipelago and Johnston Atoll: the detritivorous goldring surgeonfish, Ctenochaetus strigosus, and the planktivorous threespot chromis, Chromis verater, and Hawaiian dascyllus, Dascyllus albisella. Estimates of body condition and size-at-age varied between shallow and mesophotic depths; however, these demographic differences were outweighed by the magnitude of variability found across the latitudinal gradient of locations sampled within the Central Pacific. Body condition and maximum body size were lowest in samples collected from shallow and mesophotic Johnston Atoll sites, with no difference occurring between depths. Samples from the Northwestern Hawaiian Islands tended to have the highest body condition and reached the largest body sizes, with differences between shallow and mesophotic sites highly variable among species. The findings of this study support newly emerging research demonstrating intraspecific variability in the life history of coral-reef fish species whose distributions span shallow and mesophotic reefs. This suggests not only that the conservation and fisheries management should take into consideration differences in the life histories of reef-fish populations across spatial scales, but also that information derived from studies of shallow fishes be applied with caution to conspecific populations in mesophotic coral environments.

Spatio-temporal patterns and environmental controls of small pelagic fish body condition from contrasted Mediterranean areas

Small pelagic fish are among the most ecologically and economically important marine fish species and are characterized by large fluctuations all over the world. In the Mediterranean Sea, low catches and biomass of anchovies and sardines have been described in some areas during the last decade, resulting in important fisheries crises. Therefore, we studied anchovy and sardine body condition variability, a key index of population health and its response to environmental and anthropogenic changes. Wide temporal and spatial patterns were investigated by analyzing separately data from scientific surveys and fisheries in eight Mediterranean areas between 1975 and 2015.Results showed that anchovy and sardine body condition as well as maximum size in some areas sharply decreased in most Mediterranean areas along years (except in the Northern Alboran Sea). Despite this general pattern, well-marked environmental differences between sub-regions were highlighted by several analyses and variations in body condition were not found to be homogeneous over all the Mediterranean Sea. Further, other analyses revealed that except for the Adriatic where major changes towards a lower body condition were concomitant with a decrease in river runoffs and chl-a concentration, no concomitant environmental regime shift was detected in other areas.Together, these analyses highlighted the current poor body condition of almost all small pelagic fish populations in the Mediterranean. Yet, global environmental indices could not explain the observed changes and the general decrease in condition might more likely come from regional environmental and/or anthropogenic (fishing) effects. A prolonged state of poor fish body condition, together with an observed reduced size and early age-at-maturity may have strong ecological, economic and social consequences all around the Mediterranean Sea.

Variation in body condition of Alligator mississippiensis in Florida

We examined body condition (using Fulton’s K with snout-vent length and weight) for 482 American alligators (Alligator mississippiensis) collected from 14 aquatic sites in Florida in 2011 and 2012. An information-theoretic approach using Akaike information criterion (AIC) was used to select the best models for alligator body condition from a suite of seven candidate models created using combinations of trophic state (oligotrophic, eutrophic, hypereutrophic), sex, and alligators/km. Our top model included trophic state and alligators/km indicating that alligator body condition from sites classified as hypereutrophic and eutrophic (2.43 ± 0.07 and 2.45 ± 0.05, respectively) were greater than alligator body condition at oligotrophic sites (2.14 ± 0.01). Alligator body condition was lower at sites with a higher density of alligators ≥ 1.25 m. Across all sites, average alligator body condition ranged from 1.94 ± 0.054 (SE) to 2.78 ± 0.121(SE). This was a 43% difference in alligator body condition between the site with the highest alligator body condition (Lochloosa Lake, a hypereutrophic lake in north-central Florida) compared to the site with lowest body condition (Water Conservation Area 3B, an oligotrophic marsh in the Everglades). Across all sites, average alligator body condition was 12% greater at eutrophic and hypereutrophic sites compared to oligotrophic sites which was consistent with patterns observed in other studies for fish standing stock (highest in eutrophic lakes and lowest in oligotrophic marshes in the Everglades). The same patterns occur in alligator stomach content volume (higher in lakes in north-central Florida, Louisiana fresh, intermediate, and brackish marshes compared to the Everglades). Our results illustrate that variation in alligator body condition is consistent with patterns of aquatic site productivity and is a useful parameter for describing differences in aquatic site ecological condition.

Effectiveness of baseline corticosterone as a monitoring tool for fitness: a meta-analysis in seabirds.

Many ecosystems have experienced anthropogenically induced changes in biodiversity, yet predicting these patterns has been difficult. Recently, individual behavioural and physiological measures have been proposed as more rapid links between environmental variation and fitness compared to demographics. Glucocorticoid hormones have received much attention given that they mediate energetic demands, metabolism, and foraging behaviour. However, it is currently unclear whether glucocorticoids can reliably predict environmental and fitness-related traits and whether they may be useful in specific groups of taxa. In particular, seabirds are a well-studied avian group often employed as biomonitoring tools for environmental change given their wide distribution and reliance on large oceanic patterns. Despite the increase in studies attempting to link variation in baseline corticosterone (the primary avian glucocorticoid) to variation in fitness-related traits in seabirds, there has been no comprehensive review of the relationship in this taxon. We present a phylogenetically controlled systematic review and meta-analysis of correlative and experimental studies examining baseline corticosterone as a predictor of fitness-related traits relevant to predicting seabird population health. Our results suggest that, while variation in baseline corticosterone may be a useful predictor of larger-scale environmental traits such as overall food availability and fitness-related traits such as reproductive success, this hormone may not be sensitive enough to detect variation in body condition, foraging effort, and breeding effort. Overall, our results support recent work suggesting that the use of baseline glucocorticoids as conservation biomarkers is complex and highly context dependent, and we suggest caution in their use and interpretation as simplified, direct biomarkers of fitness.

Latitudinal dependence of body condition, growth rate, and stable isotopes of juvenile capelin (Mallotus villosus) in the Bering and Chukchi Seas

Capelin occupy a key trophic role and have a broad latitudinal distribution in the northeastern Pacific and Arctic Oceans. Understanding their adaptation to a range of conditions is important to predicting how they will respond to climate change. To quantify the variation in body condition in different physical environments, we measured energy density, RNA/DNA ratios, carbon and nitrogen stable isotope ratios in 62 juvenile capelin along the Western Alaskan coast from Bristol Bay to Point Barrow ranging across approximately 14° of latitude. Energy density correlated positively with latitude, whereas RNA/DNA (instantaneous growth index) was strongly correlated with sea surface temperature, indicating that optimal growth of capelin was achieved at ~9 °C, followed by rapid decreases in RNA/DNA ratios at higher temperatures. δ13C and δ15N had strong, inverse nonlinear relationships with latitude. Depletion of δ13C seen in capelin North of Bristol Bay may be related to the incorporation of allochthonous basal resources into the diets of juvenile capelin from nearby riverine inputs. Observed enrichment of δ15N North of Bristol Bay is likely to be related to incorporation of higher trophic level prey items. Given inverse relationship between δ13C and δ15N, these prey items are likely available due to the increased diversity of basal resources from increased inputs of riverine organic material.

Patterns of change in body condition in wintering Neotropical-Nearctic migratory birds in shaded plantations in the Andes

Despite the widely accepted idea that shaded plantations are valuable habitats for Neotropical migrants in disturbed landscapes, little empirical evidence is available in relation to the quality of this habitat for Neotropical-Nearctic migratory birds in the Andes. We evaluated the suitability of shaded plantations for overwintering Neotropical-Nearctic migratory birds by examining diurnal and seasonal variation in body condition of migrants in these agroforests in the Andes. During October to April 2008–2009 and 2009–2010, we mist-netted eight species of Neotropical-Nearctic migrants in shaded plantations in the Colombian Andes. Body condition improved throughout the day for Cerulean Warbler (Setophaga cerulea), Blackburnian Warbler (Setophaga fusca), Tennessee Warbler (Leiothlypis peregrina), and especially Canada Warbler (Cardellina canadensis). Similarly, body condition improved across the season for Tennessee Warbler, Rose-breasted Grosbeak (Pheucticus ludovicianus), and Summer Tanager (Piranga rubra). Our results provided additional evidence that several common Neotropical migrants, including species of conservation concern such as Cerulean Warbler and Canada Warbler, may improve their body condition in shaded plantations. However, about half of the species assessed in this study did not show any significant improvement in their body condition (e.g. Red-eyed Vireo). Furthermore, on average, species were in poor condition (i.e. body condition scores were negative) in these coffee farms. Thus, the extent to which this agricultural system represents high quality habitat should be looked with caution. Overall, our data contribute novel information on daily patterns of body condition improvement for several common migratory birds in Andean shaded plantations.

Growth and body condition variation of the giant mudskipper Periophthalmodon schlosseri in dry and wet seasons

This study provides information on the growth and body condition variation of the giant mudskipper Periophthalmodon schlosseri between gender and fish size during dry and wet seasons. A total of 367 fish specimens was collected along mudflat and mangrove forest in Tran De from May 2014 to April 2015. The sex ratio of this fish was nearly 1:1. This species showed isometric growth as its slope value was close to the standard threshold (e.g., 3), and its length-weight relationship was similar in both dry and wet seasons. Although the condition factor of this mudskipper varied with seasonal change and fish size, it was similar in males and females and close to well-being value (e.g., 1). These results indicated that this fish lives well and can become a potential fish for aquaculture in this area, and provides useful information for our knowledge to other gobiid fishes.

Temporal and geographical variation in body condition of common minke whales (Balaenoptera acutorostrata acutorostrata) in the Northeast Atlantic

The common minke whale (Balaenoptera acutorostrata acutorostrata) is a boreo-arctic species, and the summer period is generally characterized by intensive feeding and consequently seasonal fattening at high latitudes. The fat deposited is stored as energy reserves for overwintering at lower latitudes where feeding is greatly reduced. It is therefore expected that their body condition on the summer grounds will reflect food availability during their most intensive feeding period and thus indicate how well the high-latitude ecosystems can support the populations. During the commercial catch operations on feeding grounds in Norwegian waters, body condition data (blubber thickness and girth) were collected from 10,556 common minke whales caught from 1993 to 2013. To investigate associations between condition and time/area, we applied the following three models: (1) multiple regression models with covariates, sex, year, latitude and longitude, to find significant coefficients of the covariate; (2) random effect models involving the random effects of variations by year or area and with sex as a fixed variable; (3) varying coefficient models, which were applied to investigate variation with year/area and to interpret covariate effects by visualizations. The significance of the estimated coefficients can be assessed by statistical tests. In conclusion, the total trend over the 2 decades of data available suggests a decrease in minke whale condition. However, this trend was most pronounced during the high summer season when we considered the seasonal effect over the annual sampling periods from April to September.

Performance of tail‐mounted transmitters on American beavers Castor canadensis in a northern climate

Tail‐mounted transmitters have been used successfully in temperate regions of North America and Europe but have not been tested in more northern parts of American beaver Castor canadensis range. We deployed 63 tail‐mounted transmitters on adult beavers in Voyageurs National Park, Minnesota (USA; 48°30′N, 92°50′W), at the southern edge of the boreal forest. Mean transmitter retention time was 133 days (range = 18–401, SD = 101), with only 7% retained > 12 months. Males and females did not differ in retention times. Retention time was similar for transmitters deployed in fall (n = 38, = 135 days) and spring (n = 21, = 130 days). In 24 cases where we confirmed beavers lost transmitters, 63% tore through the side of the tail, 25% pulled out through a widened attachment hole, and 13% had the lock‐nut unscrew. Beavers chewed off or pulled out whip antennas on 50% of transmitters before they were detached from the tail, which reduced VHF signal strength and detection distance. The likelihood that an antenna would be damaged increased 3.8 times for each day of deployment up to 371 days. On average, beavers with transmitters lost 23% of their body mass and 26% of tail thickness over winter, and regained similar percentages over the growing season. Retention rates and retention times of tail transmitters were much lower in Voyageurs National Park relative to more southern areas in the United States where intra‐annual variability in body condition is considerably less. Our results reaffirm that methodologies developed for wildlife telemetry or other research and monitoring techniques should be tested under different environmental conditions to ensure objectives can be met in a safe and efficient manner.

Barn owls display larger black feather spots in cooler regions of the British Isles

Although, in many organisms, genotypes are adapted to specific environmental conditions, the identification of the ecological factors explaining patterns of local adaptation is not a trivial task. In relation to the cosmopolitan barn owl (Tyto alba), its plumage varies from white to dark pheomelanic and shows a difference in the number and size of black spots located at the tip of ventral feathers. The expression of these traits is strongly heritable and weakly sensitive to variation in body condition. Therefore, if owls located in cold or rainy regions are differently plumaged compared to owls living in warm or dry regions, this may not be a result of climate affecting the expression of plumage traits. Instead, different plumages might be selected under different environmental conditions. We have found that, on the British Isles, comparatively larger spots are present on barn owls found in regions that are cooler in summer. This is similar to the findings of a previous study performed in North America and on continental Europe, raising the possibility that larger-spotted barn owls better cope in cold temperatures during the rearing period or that they are better adapted to some environmental factors prevailing in cooler summers.

Differential Migration in the Common ChiffchaffPhylloscopus collybita: Sub-Saharan Wintering Grounds Host More Adults and Females as Well as Birds of Larger Size and Better Physical Condition

Summary. Avian migration strategies may include intra-specific variations, also known as differential migration. These migratory adaptations between conspecifics are particularly important given their implications for population dynamics. We aimed to examine the differential migration pattern as a function of age and sex, and whether this pattern also determines body morphology, in a passerine whose migration strategy includes movements to both pre- and sub-Saharan wintering areas. Thus, 1,100 common chiffchaffs Phylloscopus collybita were sampled during 2009–2012 at eight wintering locations within the Palearctic and Afrotropical regions. Biometric and body condition variables were studied for their relationship to geographical, climatic and productivity indexes. A higher proportion of adults and females were observed at lower latitudes. Common chiffchaffs were larger and in better body condition in sub-Saharan areas, coinciding with greater plant productivity and less annual rainfall. The selection of t...

Variation in size and condition of neonate pygmy bluetongue lizards, Tiliqua adelaidensis

Phenotypic variation among offspring of individual animals is an important life-history trait. In viviparous lizards, it could result from genetic variation of individuals and also differences in environments experienced by mothers during gestation. We investigated variation in phenotype and survival of neonate pygmy bluetongue lizards, Tiliqua adelaidensis, over three sampling years. We explored changes in body condition, using body size residuals as an index, and body size (snout-vent length (SVL) and mass) of neonates. For litters that were captured with their mothers, we hypothesised that body condition and size of offspring are influenced by the condition and size of their mothers, the presence of mothers in the burrow and litter size. We found that there were significant variations in body condition and mass of neonates among years. There was no significant relationship between neonate body condition, mass and SVL and post-partum body condition of their mothers. Results revealed that females with higher SVL produced larger litters. None of the analyses showed any effect of mother’s presence on neonate body condition, SVL or mass. Neither was there any effect of observed litter size on these parameters. Our findings have important conservation implications for this endangered species, given that the aim of conservation managers is to encourage conditions that promote optimum body condition and fitness in offspring in order to maximise their survival in fragmented habitats.

Body condition explains little of the interindividual variation in the swarming behaviour of adult male little brown myotis (Myotis lucifugus) in Nova Scotia, Canada

Two competing activities of temperate insectivorous bats during the fall swarming period have direct fitness consequences: fat storage for hibernation and mating. This study investigated whether interindividual variation in body condition (as a metric of stored fat; body mass/forearm length) correlated with reproductive status and influenced swarming behaviour of adult male little brown myotis (Myotis lucifugus (Le Conte, 1831)) in Nova Scotia, Canada. We predicted that bats in good body condition would more likely be reproductive and would be more likely to remain at, and closer to, a swarming site than males in poor body condition. As predicted, males in good body condition were more likely to be in advanced reproductive states than those in poor body condition. However, contrary to the prediction, males in good body condition spent significantly less time at the swarming site than males with poor body condition. There was no difference between bats of contrasting body conditions in the probability of relocating them or how far from the swarming site they roosted. Because variation in swarming behaviours of male M. lucifugus at a swarming site was not explained by body condition, one or more other factors (e.g., social, energetic) must be important.

Growth of the Cichla temensis Humboldt, 1821 (Perciformes: Cichlidae) from the middle rio Negro, Amazonas, Brazil

This study aimed to estimate age and growth of the peacock bass Cichla temensis from the rio Negro (Brazilian Amazonia) by analyzing scale annuli. Specimens were captured between October 2011 and September 2012 in the main channel of the river and in adjacent lakes in the municipality of Barcelos, AM, Brazil. Six growth checks were identified on the scales of specimens. The annual variation in body condition observed suggests that fat is accumulated during the dry season. Results for the GSI (gonadosomatic index) showed that peak reproduction occurred in the receding-water period, indicating that the fish had energy deficiencies as a result of reproductive activity. RMI (relative marginal increment) analysis revealed that an annulus is formed once a year during the receding-water period. The population parameters estimated were L50 (length at sexual maturity) = 31.11 cm, L∞ (asymptotic length) = 68.05 cm, k (growth coefficient) = 0.20.year-1 and A0.95 (longevity) = 14 years. Our results corroborate the validity of using growth rings in scales as indicators to estimate the age and growth rate of Cichla temensis in the middle rio Negro.