Body Condition Index Research Articles

Adipose tissue estimation of foraging and nesting green turtles Chelonia mydas using bioelectrical impedance analysis

Adipose tissue is the main energy store in sea turtles and fluctuates in response to dietary conditions and external stressors. Monitoring programmes commonly use body condition indices (BCIs) to infer the nutritional and health status of sea turtle populations. However, BCIs have poor predictive power for estimating adipose tissue. We introduce the use of bioelectrical impedance analysis (BIA) as a portable technique to estimate adipose tissue in green turtles Chelonia mydas. The aims of this study were to estimate adipose tissue of green turtles on the Great Barrier Reef (Australia), and to examine whether adipose tissue is a more sensitive indicator than BCI. Turtles (n = 250) were sampled at 3 foraging sites and at a nesting beach with differing levels of anthropogenic impact. Differences in adipose tissue, Fulton’s BCI, and body mass across study sites and life stages were assessed by conducting linear mixed effects models. BIA estimates of mean adipose tissue revealed significant differences across life stages and sampling sites, that were not found using BCI data. Mean adipose tissue was estimated to be 4.6 ± 0.6% (% body mass ± SD) and was not correlated with mean BCI (1.2 ± 0.1). Adipose tissue was not reduced in turtles foraging at sites with a high level of anthropogenic impact. Adult turtles had significantly higher adipose tissue values than juveniles and subadults. Adult females measured during and shortly before nesting season had the highest adipose tissue values (%). BIA is a practical method for estimating adipose tissue, and we recommend this technique for consideration in sea turtle monitoring programmes.

Validation of a microwave energy meter to non-lethally estimate energetic reserves in adult sturgeon.

Whole-body (WB) energetic reserves influence fish survival, growth, and reproduction but are typically quantified using lethal methods (i.e. proximate analyses) or interpreted through body condition indices. Energetic reserves can impact population dynamics through influences on growth rates, age-at-first-reproductive-maturity, and spawning periodicity at the individual-fish level, especially in long-lived sturgeon species. Therefore, a non-lethal tool to track the energetic reserves of endangered sturgeon populations could inform adaptive management and further our understanding of the sturgeon's biology. The Distell Fatmeter is a microwave energy meter that has been validated to non-lethally estimate energetic reserves in some fish species, but never successfully for sturgeon. Here, stepwise linear regressions were applied to test commonly monitored body metrics and Fatmeter measurements at nine different anatomical sites on captive adult pallid sturgeon (Scaphirhynchus albus; total length of 790-1015mm; WB lipid of 13.9-33.3%) compared with WB lipid and energy content determined by proximate analyses. Fatmeter measurements alone explained approximately 70% of the variation in WB energetic reserves, which outperformed models considering body metrics alone by a margin of approximately 20%. The top-ranked models based on AICc score (second-order Akaike Information Criterion) included a combination of body metrics and Fatmeter measurements and accounted for up to 76% of the variation in WB lipid and energy. We recommend the incorporation of Fatmeter measurements at a single site located dorsally to the lateral scutes at the posterior end of the fish above the pelvic fins (U-P) into conservation monitoring programs for adult pallid sturgeon (total length [TL] ≥ 790mm; fork length [FL] ≥ 715mm) and the cautious application of Fatmeter measurements for sturgeon between 435 and 790mm TL (375-715mm FL). Measurements at this U-P site combined with body mass explained approximately 75% of the variation in WB lipid and energy.

Shifting agriculture and a depleting aquifer: implications of row-crop farming on mule deer population performance

Context Conversion of native vegetation to cropland is one of the most widespread anthropogenic landscape alterations, particularly in the Great Plains region of the United States. Mule deer occur throughout the Great Plains; however, it is the south-eastern edge of their geographical distribution, and few populations coincide with dense cropland. The rapidly depleting Ogallala Aquifer supplies irrigation to row-crops throughout the region, which will likely shift towards dryland agricultural practices in the near future. Aims We sought to understand how cropland use influences morphology, body condition indices, reproductive output, and survival of free-ranging mule deer. Methods We accumulated a multi-year, longitudinal dataset of movement and morphology for 146 mule deer in the Texas Panhandle. We linked seasonal cropland use with observed morphology, body condition metrics, and reproductive output via linear mixed-effect modelling and assessed the influence of cropland on annual survival by using Cox proportional hazard models. Key results Mule deer that did not use cropland at any time during the year exhibited morphological and nutritional indices similar to those that did; except body-fat percentage being greater for mature (≥4-year-old) males that used cropland. Further, cropland use did not predict survival probability. Analyses of cropland use during seasons defined by life-stage showed context-dependent nutritional benefits. Use of cropland during winter following reproduction demonstrated an increase in young (≤3-year-old) male antler size and body mass and summer crop use increased body condition for all males. Female mule deer that utilised cropland before pregnancy had increased probability of successful reproduction, demonstrating a potential capital investment strategy in reproduction. Conclusions Cropland does not limit morphology or survival of mule deer; however, additive use of row-crops can provide a nutritional buffer and enhanced reproductive output for individuals that choose to utilise it. Implications Our study demonstrates important population-level interactions with the environment for a species near the extent of their geographical distribution. Conversion of row-crop farming from aquifer depletion or climate shifts may not diminish mule deer populations, but these changes may alter specific habitat-nutritional health relationships that can influence population performance and future conservation efforts.

Veterinary aid clinic assessments of working ponies in West Nusa Tenggara province, Indonesia: A retrospective study

Working ponies in the West Nusa Tenggara (NTB) province of Indonesia are relied upon as the principal mode of transport. They have important cultural, logistical and One Health significance for the local community. Given the tropical climate, these ponies face well recognised health and welfare challenges. Parameters relating to the general health and welfare of the ponies were assessed following data analysis of clinical records from three veterinary clinics held in 2018 and 2019. Records relating to 454 clinical examinations of ponies (n=365 stallions) aged between 1 to 25 years (mean 7.59 ± 4.70) were analysed. The mean body condition score (1 to 5 scoring system) across all clinics was 2.89 (±0.49; range 1.5, 4.5), with no significant difference between clinics (P= 0.297). The majority of ponies (84.57%; 95% CI 80.50, 87.92; 307/363) assessed presented with tachypnoea, 37.24% presented with tachycardia (95% CI 32.78, 41.92; 159/427), 14.80% (95% CI 11.10, 19.46; 41/277) recorded rectal temperatures considered hyperthermic (>38.5°C), and 38.0% did not show obvious evidence of sweating (95% CI 32.21, 44.16; 95/250). Ponies examined at the April/May 2019 clinic were more likely to be considered hyperthermic (P=0.009) and/or presented with tachycardia (P<0.001), whereas ponies examined in the November 2019 clinic were more likely to present with tachypnoea (P=0.001). In general, the objective measures of body condition and health indices of these ponies were considered adequate. Some abnormalities relating to prolonged recovery following exercise whilst working were considered likely related to thermoregulatory stress. Parasite burdens were found to be low, no haemoprotozoan parasites were detected and median faecal egg count was zero. Measures to encourage cooling and greater frequent rest periods continued surveillance and monitoring the health of these ponies will result in both enhanced welfare and advances in One Health initiatives.

Indigenous sea gardens within the Pacific Northwest generate partial trophic niche and dietary fatty acid shifts in littleneck clams ( Leukoma staminea )

Pacific Northwest Indigenous communities historically managed terrestrial and marine environments to increase the productivity and access of traditional foods. Sea gardens, also called clam gardens, were an Indigenous aquaculture method that increased traditional food habitat for targeted food species such as bivalves. This study utilized fatty acid biomarker analysis alongside stable isotopic analysis with bivalve condition indices of traditionally harvested littleneck clams (<em>Leukoma staminea</em>) to investigate dietary and trophic differences between sea gardens and non-walled beaches in Kanish Bay, Quadra Island, British Columbia. We utilized non-metric multidimensional scaling, distance-based redundancy analysis (db-RDA), and Bayesian three-source isotopic mixing models to examine impacts of environmental drivers on bivalve dietary composition and condition at four sea garden sites and four non-walled sites. Bivalve tissue saturated fatty acids (sum SFAs) showed statistical significance (Mann-Whitney U-Test, W = 3447, P ≤ 0.01), indicating that sea garden clams (x̅ = 34.96; SD = 7.56) had higher mean relative percent areas of SFAs compared to non-walled sites (x̅ = 31.76; 7.71). Bivalve monounsaturated fatty acids (MUFAs) showed statistical significance (Mann-Whitney U-Test, W = 1202, P ≤ 0.01, a = 0.05), indicating sea garden clams (x̅ = 3.48; SD = 3.78) had lower mean relative percent areas of MUFAs compared to those in non-walled sites (x̅ = 6.97; SD = 5.90). Sea garden bivalves were found to feed at a higher trophic level, with a slimmer dietary range, compared to non-walled clams. Both dietary marker differences and differentiated trophic positioning suggest decreased physiological stressors impacting feeding of bivalves, differences in dietary particulate intake, or a combination of both occurring at sea garden sites compared to non-walled sites. Correlations within a db-RDA indicate that bivalves with high body condition indices at sea garden sites were benefiting from decreased stress related to favorable salinity and oxygen parameters, which positively impacted bivalve feeding and respiration. Observed trophic niche differences and fatty acid differences would also be explained by this suggested mechanism. We conclude that partial trophic shifts and fatty acid changes of sea garden <em>L. staminea</em> bivalves are consistent with stress-alleviated bivalve responses, and match correlated variables in our db-RDA. Trophic niche differences and fatty acid shifts between sea gardens and non-walled sites should be further explored by using a quantitative method to identify sea gardens from non-walled sites in addition to established field verification methods.

ВЫРАЩИВАНИЕ ТЕЛОК МОЛОЧНОГО НАПРАВЛЕНИЯ

This article shows the results of scientific research on raising the Holstein-Friesian heifers from birth to 12 months of age, with the introduction to their feeding regimen of "Neomilk" whole milk replacer, as well as the "Gavryusha" commercial prestarter and starter during the preweaning period and the extruded feed called "NFT KATU," produced by S. Seifullin Kazakh Agrotechnical Research University during the preweaning and postweaning periods. Three groups of calves were formed using a pair-matching method for the main research. Studies on body weight dynamics were conducted at the Aina Dairy Farm LLP with the calculation of daily average, relative, and absolute weight gains. At three months of age, the body weight of heifers in the second test group exceeded that of the control and the first test group by 7.8 kg (8.8%) and 6.8 kg (7.7%), respectively. At six months of age, the difference increased to 34.4 kg (30.7%) and 23.4 kg (19.2%). By 12 months of age, the gap widened to 106 kg (47.3%) and 77 kg (33.4%). Outline characteristics were also analyzed by taking measurements and calculating body condition indexes of the heifers. An analysis of the feeds used in animal feeding was conducted. The chemical composition analysis of the feeds revealed that the extruded feed had the highest protein content reaching 12.9%, which was 2.8% and 1.5% more than bran and "Gavryusha" prestarter, respectively.

Relative Condition Parameters for Fishes of Montana, USA

Body condition indices are commonly used in the management of fish populations and are a surrogate to physiological attributes such as tissue-energy reserves. Relative condition factor (Kn) describes the condition of species relative to populations in a geographic area. We developed models to allow for the calculation of Kn in Montana, USA by using the weight–length data collected by Montana Fish, Wildlife &amp; Parks. We generated log10weight–log10length relationships to obtain Montana specific parameter estimates for relative condition equations (W′) for 51 species and three subspecies. We developed separate models by water type (e.g., lotic and lentic) and sex for five species due to varying growth based on sexual dimorphism and varying ecosystem types. Relative condition offers the advantage of describing body condition relative to species in Montana, provides a condition index for species that do not have standard-weight models developed for relative weight (Wr), and affords more information for the global database on weight–length relationships of fishes.

Hidden Hippos: Using Photogrammetry and Multiple Imputation to Determine the Age, Sex, and Body Condition of an Animal Often Partially Submerged

Demographic Information on threatened species is important to plan conservation actions. Due to their aquatic lifestyle, the subtle nature of hippo sexual dimorphism, and their occurrence in inaccessible areas, it is difficult to visually determine hippo ages and sexes. Previously, hippo body lengths have been measured from drone images and used to estimate age. However, due to hippos’ propensity to be partially submerged, it is often difficult to obtain the required measurements. We used the novel technique of multiple imputation to estimate missing body measurements. Further, we explored if male and female hippos could be differentiated in drone images based on body proportions, also examining body condition indices and how these varied seasonally. Multiple imputation increased the number of hippos that we aged threefold, and the body lengths we obtained fell within the range provided in literature, supporting their validity. We provide one of the first age structure breakdowns of a hippo population not from culled hippos. Accounting for overall size, males had wider necks and snouts than females. Hippo body condition varied seasonally, indicating responses to resources and reproduction. We provide a new technique and demonstrate the utility of drones to determine age and sex structures of hippo populations.

Seasonal variation in testicular biometry of wild boar in the game preserve

The increase in wild boar numbers in recent decades is partly due to the involvement of most young females in reproduction as early as their first year of life. After the rut of adult females is over, young females are still entering oestrous as they attain maturity, prolonging the rutting period by several months. This study aimed to evaluate the effect of seasonality on the growth rate of male wild boar bodies, the growth of piglet and yearling male wild boar gonads, and sperm concentration in the epididymides. We found that yearlings' weight and body length were almost constant in summer and autumn, with a sharp increase in winter. Seasonality was also reflected in the body condition index, which rose by more than 41% between summer and winter. In terms of seasonality, the testimetric dimensions again differed significantly only in winter. Sperm were recorded in piglets weighing more than 15 kg. Regardless of the time of capture, 41% of piglets were examined as juveniles, only 6%, resp. 8% of piglets reached low or medium concentration values. While 10% of all yearling males were azoospermatic (juvenile), regardless of weight, there was evidence of seasonality in the proportion of males with measurable concentrations. These concentrations gradually increased from 62.5% in summer to 78.6% in winter. No sterile male over two years of age was noted. The results show that even in wild boars, there is a culmination not only of physical characteristics in winter but also a culmination of testimetric dimensions. Sperm already occur in 15 kg of piglets, which means they can theoretically participate in the fertilisation of female piglets.

Call rate as an index of nest count in wading bird colonies

Traditional monitoring methods for colonial waterbirds, such as nest counts, can be expensive, time‐intensive, disruptive to nesting birds and limited by colony accessibility. Our study tested the use of acoustic sampling as a colony monitoring technique for three species of colonially nesting herons (Ardeidae) by quantifying the relationship between chick call rate and nest count in colonies. Because acoustic detection can be influenced by soundscape variables, we measured day since colony initiation, body condition index of small heron chicks, nest height, vegetation density and wind speed and evaluated their effects on call rate detection. Generalized linear mixed‐effects models showed that call rate detection increased with daily nest count for all species. Snowy Egret Egretta thula and Tricoloured Heron Egretta tricolour detected call rate was also dependent on environmental, temporal and physiological variables, whereas Great Egret Ardea alba call detection was affected by vegetation density around nests and wind speed. Our study showed that wading bird nest counts can be estimated using acoustic sampling, reducing the need for manual colony surveys, and facilitating long‐term monitoring of wading bird nesting trends, which are important measures of wetland restoration worldwide.

Field-based adipose tissue quantification in sea turtles using bioelectrical impedance spectroscopy validated with CT scans and deep learning.

Loss of adipose tissue in vertebrate wildlife species is indicative of decreased nutritional and health status and is linked to environmental stress and diseases. Body condition indices (BCI) are commonly used in ecological studies to estimate adipose tissue mass across wildlife populations. However, these indices have poor predictive power, which poses the need for quantitative methods for improved population assessments. Here, we calibrate bioelectrical impedance spectroscopy (BIS) as an alternative approach for assessing the nutritional status of vertebrate wildlife in ecological studies. BIS is a portable technology that can estimate body composition from measurements of body impedance and is widely used in humans. BIS is a predictive technique that requires calibration using a reference body composition method. Using sea turtles as model organisms, we propose a calibration protocol using computed tomography (CT) scans, with the prediction equation being: adipose tissue mass (kg)=body mass - (-0.03 [intercept] -0.29 * length2/resistance at 50 kHz +1.07 * body mass -0.11 * time after capture). CT imaging allows for the quantification of body fat. However, processing the images manually is prohibitive due to the extensive time requirement. Using a form of artificial intelligence (AI), we trained a computer model to identify and quantify nonadipose tissue from the CT images, and adipose tissue was determined by the difference in body mass. This process enabled estimating adipose tissue mass from bioelectrical impedance measurements. The predictive performance of the model was built on 2/3 samples and tested against 1/3 samples. Prediction of adipose tissue percentage had greater accuracy when including impedance parameters (mean bias=0.11%-0.61%) as predictor variables, compared with using body mass alone (mean bias=6.35%). Our standardized BIS protocol improves on conventional body composition assessment methods (e.g., BCI) by quantifying adipose tissue mass. The protocol can be applied to other species for the validation of BIS and to provide robust information on the nutritional and health status of wildlife, which, in turn, can be used to inform conservation decisions at the management level.

Evaluating Mechanisms of Short-term Woodland Salamander Response to Forest Management.

Contemporary forest management often requires meeting diverse ecological objectives including maintaining ecosystem function and promoting biodiversity through timber harvesting. Wildlife are essential in this process by providing ecological services that can facilitate forest resiliency in response to timber harvesting. However, the mechanisms driving species' responses remain ambiguous. The goal of this study was to assess mechanisms influencing eastern red-backed salamander (RBS; Plethodon cinereus) response to overstory cover removal. We evaluated two mitigation strategies for the RBS in response to overstory removal. We used a before-after-control-impact design to study how (1) retaining residual trees or (2) eliminating soil compaction affected RBS surface counts and body condition index (BCI) up to two-years post-treatment. Additionally, we assessed how surface counts of RBS were influenced by overstory tree cover. Surface counts of RBS were not strongly influenced by overstory removal when tree residuals were retained. Body condition index increased in treatments where harvest residuals were retained. In treatments where soil compaction was eliminated, surface counts and BCI were inversely related. Finally, surface counts from both mitigation strategies were not strongly influenced by overstory cover. Overall, both mitigation techniques appeared to ameliorate impacts of overstory removal on RBS. These results highlight the importance of understanding mechanisms driving species' responses to forest management. To reduce the perceived negative effects of overstory removal on RBS, incorporating these mitigation measures may contribute to the viability and stability of RBS populations. Incorporating species' life history traits into management strategies could increase continuity of ecological function and integrity through harvesting.

Differences in the morphological body condition index of sea turtles between species and size classes

AbstractThe body condition of animals is an important indicator of their habitats and the effects of anthropogenic activities and pollution. Body condition indices calculated from morphometric measurements have been widely employed as they are easy to use and inexpensive. In sea turtles, Fulton's condition index, calculated as the bodyweight divided by the cube of straight carapace length (SCL), has been commonly used and it has been proposed that an index of ≥1.2 indicates a good body condition. However, comparing Fulton's condition index between different species and size classes is problematic as it does not consider the mass-length relationship. In this study, we conducted a meta-analysis to evaluate the differences between sea turtles. A literature review indicated that most studies reported the SCL-based Fulton's condition index for green turtles (Chelonia mydas), followed by loggerhead turtles (Caretta caretta) and hawksbill turtles (Eretmochelys imbricata). Therefore, we compared the values reported for healthy turtles of these three species. Meta-analysis supported the adequacy of 1.2 as a threshold in juvenile and adult green turtles and large juvenile and adult loggerhead turtles. High Fulton's condition index values were found for hatchlings and post-hatchlings of all three species and small loggerhead turtle juveniles. Low Fulton's condition index values were found for hawksbill turtles, particularly small juveniles. The differences in the Fulton's condition index between species and size classes indicated that it should be used carefully as a threshold for health condition evaluation.

Identification of potential welfare and survival indicators for stranded cetaceans through international, interdisciplinary expert opinion.

Management of live cetacean strandings generally focuses on refloating animals, yet there is a lack of scientific data to inform decision-making. Valid indicators that are practical to measure are needed to assess welfare status and survival likelihood for stranded cetaceans. The Delphi method was applied to gather international and interdisciplinary expert opinion to provide face validity to potential indicators of stranded cetacean welfare and survival likelihood. Two online questionnaires were conducted. In the first questionnaire these experts identified potential indicators of stranded cetacean welfare and survival likelihood. These indicators were subsequently scored by the same experts in questionnaire two, based on their value for assessing welfare/survival likelihood and being practical to measure. Indicators considered valuable and practical for assessing welfare and survival likelihood at strandings included animal-based indices of body and skin condition, signs of physical trauma, respiration rate and various behaviours. Resource-/management-based indicators related mainly to human intervention and should be correlated with animal-based indices to provide relevant evaluations. Importantly, inextricable links between welfare and survival for stranded cetaceans are emphasized, with 90% of indicators being similar for both. Investigations into these indicators should be conducted to develop a practical, science-based assessment framework to inform decision-making during stranding events.

Host-Parasite Relationship-Nematode Communities in Populations of Small Mammals.

Simple SummaryIntestinal nematodes were analyzed in three small rodent species: Apodemus sylvaticus, Apodemus flavicollis, and Myodes glareolus. In total, 15 species of nematodes were identified. We studied the relationship between the parasitological parameters (individual parasite species richness IndPSR and individual parasite load IndPL) and morphological characteristics (body mass, body condition index BCI, and spleen mass). In all of the studied species, our results showed that animals in a better condition (BCI) had significantly higher parasite species richness, as we had expected. Furthermore, we showed that females of the same BCI as males were parasitized with more parasite species in A. flavicollis. Contrary to our expectations, the spleen mass did not reflect changes in the level of parasitism, but in M. glareolus, a smaller spleen was related to a higher parasite load. Since the spleen is just part of the complex immune response, it is possible that the presence of nematode parasite species provokes, in small rodent species, a response at the other levels of the immune system.Nematode burdens and variation in morphological characteristics were assessed in eighty-eight animals from three host species (Apodemus sylvaticus, Apodemus flavicollis, and Myodes glareolus) from eight localities in Serbia. In total, 15 species of nematodes were identified, and the overall mean parasite species richness (IndPSR) was 1.61 per animal (1.98 in A. flavicollis, 1.43 in M. glareolus, and 0.83 in A. sylvaticus). Furthermore, the studied host species significantly differed in individual parasite load (IndPL) and in the following morphological characters: spleen mass, body condition index (BCI), and body mass. We aimed to analyze the relationship between the burden of intestinal nematodes, on one hand, and the body conditions of the host and its capability to develop immune defends on the other. Spleen mass was considered as a measure of immune response. In all host species, larger animals with a better condition (higher BCI) were infected with more parasites species (IndPSR), while parasite load was not related to BCI. Only in A. flavicollis were males significantly larger, but females of the same sizes were infected with more parasite species. This female-biased parasitism is contrary to the theoretical expectation that males should be more parasitized, being larger, more active, with a wider home range. Although the spleen size was significantly correlated with body condition and body mass, IndPSR was not related to spleen mass in any studied species, but in M. galareolus, we found that a smaller spleen was related to higher infection intensity (IndPL).

Senescence and Differential Size-Based Survival in Puerto Rican Giant Groundlizards, Pholidoscelis exsul (Squamata: Teiidae), on Guana Island, British Virgin Islands

Invasive species are a major threat and primary driver of vertebrate extinctions on islands, including native and endemic lizards such as West Indian Groundlizards (Genus Pholidoscelis). The genus comprises 19 extant species that range collectively from the Bahamas through the Greater Antilles south to Dominica in the Lesser Antilles. Few studies have addressed aspects of Groundlizard population ecology despite invasive mammals being implicated in Groundlizard declines and three extinctions. From 2007 to 2011, we conducted a capture–recapture study of Puerto Rican Giant Groundlizards (Pholidoscelis exsul) on Guana Island. Guana Island is privately owned and hosts a small number of feral cats, but is mongoose-free and has otherwise experienced only minor human modification since the mid-18th Century. Thus, the island provides a unique opportunity to study lizard demography under conditions minimally impacted by human activities. Our objective was to establish benchmark demographic parameter estimates of P. exsul that may be used in future studies to detect ecological changes. We hypothesized that lizards would be encountered more frequently in disturbed habitat than in less-disturbed habitat because of available anthropogenic food subsidies. We also predicted that large lizards would have higher annual survival rates than would small lizards, and lizards with higher indices of body condition would have correspondingly higher annual survival rates than lizards of the same size class with lower indices of body condition. Our results showed that male growth rates were comparable to similar studies, and individuals reached the presumed size of sexual maturity within 1 yr, with growth rates declining thereafter. Annual survival increased with size class (small = 0.155, 95% confidence interval [CI] = 0.069–0.312; large = 0.518, 95% CI = 0.374–0.660), but we found no evidence of a body condition effect on annual survival. The probability of mortality increased to 99.4% by age 6, but evidence of senescence via declining body condition was apparent sooner. Daily capture probabilities were higher in heavily modified habitat (0.081, 95% CI = 0.049–0.132) than in relatively natural habitat (0.025, 95% CI = 0.012–0.054). Mean maximum distance moved between recaptures was 24.4 m (2–350 m). Estimates of annual abundance ranged from 139 to 250 individuals. Density estimates among years based on the upper confidence limit ranged from 41.9–81.5 individuals/ha within the core sampling area (6.01 ha) and 20.1–39.2 individuals/ha when a 12.5-m buffer strip was incorporated into the effective sampling area.

Dietary yolk supplementation decreases rates of yolk deposition in Japanese quail.

Generation of egg yolk by birds requires the synthesis and deposition of large amounts of protein and lipid, and is often accompanied by the incorporation of additional physiological mediators. While there has been much work examining the relative quantities of yolk components, as well as potential adaptive patterns of their allocation, we still do not have a full understanding of what controls yolk formation and composition. Once ovarian follicles are recruited into the preovulatory hierarchy, the yolk is deposited in concentric rings, with one ring deposited per day. Previous studies have shown that there is substantial interspecific and intraspecific variation in the number of rings in yolks, and thus the number of days it took those yolks to grow. We hypothesized that the ability to grow follicles to maturity quickly is limited by the availability of materials to make yolk precursors in the female, either in body reserves or in dietary access. To test this, we supplemented the diets of Japanese quail with hard-boiled chicken yolk and examined the influences of treatment and female body condition on follicle growth rates. Contrary to predictions, females with higher body condition indices produced yolks that grew more slowly, and yolks from supplemented birds grew more slowly than controls. These results indicate that females can modulate the rate of yolk incorporation into developing follicles, and that an energy balance that is too high may not be optimal for the fast growth of developing ovarian follicles.

Stable Isotope Analysis Supports Omnivory in Bank Voles in Apple Orchards

With only periodic and incomplete studies of its diet over time, all with differing methods and conclusions, the degree of omnivory in the bank vole (Clethrionomys glareolus) is not fully clear. We assessed the trophic niche of the species using isotopic (δ15N and δ13C) compositions from hair samples and analysed how C. glareolus shares trophic space with herbivores, granivores and insectivores living syntopically. According to the numbers trapped, C. glareolus was the fourth most numerous species in the apple orchards that we investigated, accounting for 14.4% of all trapped small mammals with a relative abundance of 1.12 individuals per 100 trap nights. The average values of both δ15N and δ13C in the hair of C. glareolus differed from the other trophic groups, with the average of δ15N in orchards and neighbouring habitats (6.55–6.95‰) being closest to that of insectivores. Intraspecific trophic niche differences (depending on age, gender and reproductive status) were not expressed, while correlations between body mass, body condition index and both δ15N and δ13C values were not consistent. In comparison to analysed basal resources, isotopic signatures in the hair were closest to the values in invertebrates and apple seeds. The degree of omnivory in C. glareolus was not the same in different habitats. This may be an indication of ecological plasticity within the species, allowing its inclusion/success in multi-species small mammal communities.

Health status indices of Kelp Gull populations in South Africa

ABSTRACT Kelp Gulls Larus dominicanus are widespread globally due to their ability to exploit a wide variety of resources and foraging habitats inland, in coastal areas and offshore. However, the increasing availability of anthropogenic diet items might potentially impact the health of their populations. We investigated body condition and parasite loads of incubating adult Kelp Gulls and their chicks at seven South African breeding colonies with varying proximity to landfills. Adult body condition indices did not differ significantly among colonies during the incubation period but were on average highest at one of the urban colonies, Strandfontein, which is next to a large landfill site in Cape Town. The only blood parasite identified was Haemoproteus spp. Prevalence overall was low, but significantly higher in adults than in chicks. Yeast cells (Candida spp.) were identified in faecal smears and coincided with higher body condition index values in incubating adults. Our results suggest that urban landscapes currently have little impact on these aspects of gull health, at least on individuals in good enough condition to breed.

Corn-starch based formulated diet has growth and feed utilization efficiency advantages over trash fish diet for juvenile golden pompano Trachinotus ovatus

Until now, trash fish/low valued fish continues to be widely used in marine cage culture of pompano and many other carnivorous species in China and other Asian countries. This study is the first attempt to compare the performance of juvenile golden pompano Trachinotus ovatus fed trash fish or starch-based formulated diets. Three isonitrogenous (41 %) and isolipidic (11 %) diets containing 16, 22 or 28 % corn starch were prepared. Juvenile pompano (mean initial weight: 28.0 ± 0.3 g) were fed either formulated diets or trash fish on a equivalent dry-matter basis for 8 weeks. The survival rates were significantly higher in fish fed starch diets than fish fed trash fish (P < 0.05). Specific growth rate (SGR) of fish fed the 22 % and 28 % starch diets was significantly higher than fish fed 16 % starch diet and trash fish. Feed intake (FI) of fish fed trash fish was significantly higher than those fed formulated diets; however, feed efficiency (FE) and protein efficiency ratio (PER) of fish fed the formulated diets were higher than those fed trash fish, with the 22 % starch dietary group having a significantly higher FE value than fish fed trash fish. The whole-body energy retention (ER) of fish fed the diet containing 22 % starch had the highest ER, significantly higher than those fed 16 % starch and trash fish. The moisture in whole-body tissues of fish fed trash fish was significantly higher than the formulated dietary groups. On the other hand, whole-body protein and lipid contents of fish fed the 22 % starch diet was significantly higher than the other dietary treatments. The whole-body lipid level of fish fed trash fish was significantly lower than the other dietary groups. The body condition indices were significantly higher for fish fed formulated diets compared to those fed trash fish. The viscerosomatic index (VSI) was decreased with increasing dietary starch levels. Hexokinase (HK) activity significantly increased with increasing dietary starch levels, whereas pyruvate kinase (PK) activity had an opposite trend. The liver and muscle glycogen contents were generally increased with increasing dietary starch levels. In addition, the intestinal microbial communities of fish fed the formulated diets and trash fish was distinctly different. The results shown that formulated diet had advantages in performance and feed utilization efficiency over trash fish. Corn starch can be used as a suitable dietary carbohydrate. Evaluated on growth and FE, the optimal dietary corn starch level for T. ovatus is 22–24 % of diet.