Homelessness and dog ownership: an investigation into animal empathy,attachment, crime,drug use,health and public opinion

Abstract

A sample of 51 homeless people in Cambridge, UK completed a questionnaire featuring adapted Animal Empathy and Companion Animal Bonding Scales. Concepts of crime, drug use, and health matters amongst the homeless, both dog owning and non-dog owning, were investigated, as well. Ninety members of the general public completed a similar questionnaire which sought their opinions on homeless people who own dogs. There was a highly significant difference (p < 0.01) between the homeless and the securely housed on their animal empathy and attachment scores, with the homeless sample displaying higher values. Gender and dog ownership status had no effect on these scores. A near significant result (U = 2, n₁ = 13, n₂ = 58, p = 0.06) was revealed for animal empathy scores of those who gave money to dog-owning homeless people and those who gave to non-dog owning homeless people. Of the public respondents, women were significantly more likely to show concern for a homeless person's dog's welfare than men (X²₍₁₎ = 8.5, p < 0.01), and of the homeless respondents, non-dog owners were significantly more likely than dog owners to believe that having a dog helped initiate conversations with the public (X²₍₁₎ = 4.0, p < 0.05). Highly significant differences (U = 10, n₁ = 31, n₂ = 20, p < 0.01) were found for medical care use between the dog-owning and non-dog owning homeless, and health scores showed a reversed trend compared to that expected for the general population, with dog owners scoring lower than non-dog owners.     

Male Mate Choice in Lemur catta

Though females are generally more selective in mate choice, males may also derive reproductive benefits from exercising mate selectivity if one or more factors limit male reproductive success and females differ in reproductive potential. I used male mating effort as a proxy for male mate choice in ring-tailed lemurs (Lemur catta). I calculated mating effort as the rate of male-male agonism during each female's estrous period 30 min before and 30 min after the first and last mountings with intromission. I collected data on 1 free-ranging Lemur catta troop during 2 consecutive breeding seasons on St. Catherines Island, USA. In both yrs, male mating effort differed significantly among troop females once I adjusted male-male agonistic rates to reflect agonistic intensity, and I corrected for the number of observed mates per female (2000: χ² = 27.43, df = 3, p < 0.0001; 2001: χ² = 21.10, df = 3, p < 0.001). Results strongly suggest male mate choice. Contrary to expectation, males did not expend the greatest mating effort for females with the highest dominance status nor the highest reproductive success. Males preferred females that either: (1) belonged to the age class in which fecundity and infant survival is the highest at this site (4–9 yrs), or 2) were older females (≥10 yrs) with high reproductive success. Female reproductive potential appears to be an important variable determining male mating effort in Lemur catta.     

Dental anomalies in the gray foxUrocyon cinereoargenteus and the red foxVulpes vulpes

We examined dental anomalies, including oligodonty, polydonty, connation, rotation, and misalignment in 510 gray foxes and 150 red foxes from southern Illinois (USA). Dental anomalies were significantly more common (x ² = 11.5, df = 1,p < 0.001) in gray foxes (n = 177; 34.7% of sample) than red foxes (n = 25; 16.6% of sample), and more common in male than female gray foxes (x ² = 3.88, df = 1,p < 0.05). Polydonty was very uncommon, as expected for species in which the normal dental complement is close to the primitive eutherian number. In both species, the most prevalent anomaly was loss of the last lower molar. Loss of the upper or lower first premolar was also common. Thus, oligodonty almost always involved the smaller anterior (P¹ and P₁) or posterior (M₃) teeth of the dental arcade. Conversely, the large carnassial teeth, with complex occlusal patterns and shearing surfaces, appeared to be highly conserved with only three anomalous individuals (0.4%) among all specimens.     

Trace element and magnesium levels and superoxide dismutase activity in rheumatoid arthritis

It has been suggested that reactive oxygen metabolites and trace elements play some role in the etiology and pathogenesis of rheumatoid arthritis (RA). Superoxide dismutase (SOD) is believed to exert an important protective role against oxygen toxicity. The aim of the study was to investigate the probable changes in the levels of trace elements and SOD activity in RA. Plasma and erythrocyte copper, zinc, and magnesium levels and erythrocyte SOD activity were measured in groups of controls and RA cases. Significantly increased erythrocyte SOD activity was found in RA patients in comparison with controls(p < 0.0001). A rise in erythrocyte Zn level(p < 0.0001) and plasma Cu level(p < 0.0001) and a decrease in erythrocyte Cu level(p < 0.05) and plasma Zn level(p < 0.05) were obtained in RA patients when compared to controls. Plasma and erythrocyte Mg levels of the RA patients showed slight and statistically insignificant reductions when compared to controls(p > 0.05). In RA patients, there were positive correlations between erythrocyte SOD activity and Mg level (r = 0.4345,p < 0.01) and between erythrocyte Zn level and plasma Cu level(r = 0.4132,p < 0.01). There were negative correlations between erythrocyte SOD activity and plasma Zn level(r =-0.3605,p < 0.05) and between plasma Zn level and erythrocyte Cu level(r =-0.4578,p < 0.01) in RA patients. This work was presented at the International Congress on Free Radicals in Health and Disease, 6–10 September 1995, Istanbul, Turkey.     

Measurements of the gas temperature in an oxygen plasma by spectroscopy of the O2( b 1Σ g+ ) → O2( X 3Σ g? ) transition

A method for measuring the gas temperature in an oxygen plasma by spectroscopy of the electronic transition from the O₂(b ¹Σ _g ⁺ , v = 0) metastable state of molecular oxygen into the O₂(X ³Σ _g ⁻ , v = 0) ground state is considered in detail. The method is verified experimentally for the plasma of dc glow discharge in pure oxygen. It is shown that the gas temperature can be determined by analyzing high-resolution spectra of the P branch of this transition, no matter whether its fine structure (^P P and ^P Q branches) is resolved or masked, provided that the rotational structure of the spectrum is resolved. The feasibility of the method proposed in 1999 by P. Maco and P. Veis for determining the gas temperature from the ratio between the intensity maxima of the R and P branches of the O₂(b ¹Σ _g ⁺ , v = 0) → O₂(X ³Σ _g ⁻ , v = 0) transition in a poorly resolved spectrum was studied experimentally. It is shown that, in order to use this method, it is necessary to know the spectrograph instrumental function. The effect of the spatial inhomogeneity of the temperature and concentration of O₂(b ¹Σ _g ⁺ ) molecules on the accuracy of integral (over the plasma volume) measurements of the gas temperature is investigated using spatially resolved spectroscopy of the O₂(b ¹Σ _g ⁺ , v = 0) → O₂(X ³Σ _g ⁻ , v = 0) transition. It is shown that precise measurements of the temperature require that the optical measurement system be thoroughly adjusted in order for the temperature and concentration of the emitting particles to vary insignificantly over the optically selected volume. Original Russian Text ? S.M. Zyryanov, D.V. Lopaev, 2007, published in Fizika Plazmy, 2007, Vol. 33, No. 6, pp. 563–574.     

The Andean bear alopecia syndrome may be caused by social housing

The Andean bear alopecia syndrome is a progressive and chronic condition documented in ex situ populations. Recent advances focus on treating symptoms, not preventing future cases. We therefore explored the epidemiology of this syndrome through an analysis of husbandry and veterinary conditions of 63 Andean bears (26M:37F) housed in North and South American zoos and other ex situ circumstances. We had the most complete information for the North American population and found that 29% of females (n = 24) were affected. No males (n = 26) were affected. An analysis of generalized linear models indicated that three models were competitive in describing the occurrence of the condition (i.e., ΔAIC_c ≤ 2): the model including only the individual's sex (χ² = 13.41, df = 1, p < .001), the model including both individual sex and social housing status (χ² = 1.36, df = 2, p < .001), and the model including both individual sex and the expression of stereotypical behaviors (χ² = 13.82, df = 2, p = .001). Stereotypical behaviors were common among both males (50%, n = 26) and females (51.9%, n = 27) whether or not they were affected, but the syndrome was seen only in females who had been socially housed. Therefore, we suggest that the Andean bear alopecia syndrome is a symptomatic response to the long‐term social housing of bears that would otherwise not live socially. To prevent new cases, we recommend that female Andean bears be housed with adult conspecifics only when females choose to cohabitate.     

COVID-19 y personas mayores en residencias: impacto según el tipo de residencia

PurposeTo find out whether elements such as public expenditure, the coverage ratio, public or private ownership, and the size of Nursing homes relate to the number of deaths in residences per COVID-19.Material and methodsA total of 15 variables are analyzed in 17 Autonomous Communities (n = 17), where the following stand out: public expenditure per dependent person; incidence of COVID-19 in each Autonomous Community; deaths in Nursing homes by COVID-19; and analysis of places in Nursing homes. Reliability of r = 0.613. Regression analyses are carried out with the different variables, and ANOVA tests.ResultsPercentages of deaths by COVID-19 in Nursing homes, between 40% and 88%, of the total of (p < 0.001, X² = 0.975). A relationship is established between the number of deaths from COVID-19 in Nursing homes, and the higher number of private Nursing homes (p < 0.001, X² = 0.633). The larger the size of the Nursing home, the more deaths by COVID-19 were recorded (p < 0.001, X² = 0.787), with private Nursing homes having +100 places, and public Nursing homes having +100 places (p < 0.001, X² = 0.808).ConclusionsIt was found that there is a relationship between the number of deaths from COVID-19 in Nursing homes, and the fact that there are a greater number of private Nursing homes in that autonomous community. It was detected that the model of Nursing home best prepared to face the COVID-19: public Nursing homes with less than 25 places.     

Leaf area estimation in a sugar beet cultivar by linear models

An indirect method of leaf area measurement for Rizor sugar beet cultivar was tested. Leaves were sampled during two growing seasons in a Randomised Complete Block Design experiment. For 2002 samplings, leaf area [cm²] was linearly correlated with maximum leaf width [cm] using all leaf samples (r ² = 0.83, p < 0.001) or using the means of the 8 sampling occasions (r ² = 0.97, p < 0.001). Correlations between leaf area and leaf mid vein length [cm] were weaker (r ² = 0.75, p < 0.001 and r ² = 0.93, p < 0. 001, respectively). For 2003 samplings, the area estimated by the equations was highly correlated to the measured leaf area.     

Home range and habitat preference of female lions (Panthera leo persica) in Gir forests, India

The social organization of Asiatic lions (Panthera leo persica) differs from African lions (P. l. leo) in that breeding lionesses defend resource based territories while male coalitions maximize coverage of female groups. Thus, lion density in the Gir forests of India is dictated by female territory size. We studied the home range and habitat preference of lions using radio telemetry on seven lionesses spaced throughout the Gir between 2002 and 2005. Radio locations obtained by homing in were plotted on a classified (LISS III FCC) habitat map of Gir to obtain habitat use and availability. Habitat preference was computed using compositional analysis and Ivlev’s index. Average (±SE) 100% Minimum Convex Polygon (MCP) range of six lionesses was 48.2 ± 10.6 km², 95% MCP was 34.7 ± 7.8 km² and 95% fixed kernel range size was 32.5 ± 8.2 km². Breeding female group density and group size was about 3 per 100 km² and 1.3 (0.5 SD, n = 45) respectively. Lions were observed to show a habitat preference (c_(6df)² = 11. 4 \chi_{(6df)}^{2} = 11. 4 , P = 0.08), the order of preference was Moist Mixed forests > Mixed forests > Savanna habitats > Teak-Acacia-Zizyphus-Anogeissus forests > Acacia-Lannea-Boswellia forests > Thorn and Scrub forests > Agriculture areas. Habitat preference during the day was for dense vegetation (c_(6df)² = 35 \chi_{(6df)}^{2} = 35 , P < 0.001). At night lions even ventured into agricultural fields. Our data suggests that dense habitats are preferred by lions in Gir to escape the heat of the day and to be in good cover when human activity was likely to be at its peak within forested areas.     

Minimum sample sizes for identifying chromosomal fragile sites from individuals: Monte Carlo estimation

A Monte Carlo simulation procedure was used to estimate the exact level of the standardized X ² test statistic (X _s ²) for randomness in the FSM methodology for the identification of fragile sites from chromosomal breakage data for single individuals. A random-number generator was used to simulate 10 000 chromosomal breakage data sets, each corresponding to the null hypothesis of no fragile sites for numbers of chromosomal breaks (n) from 1 to 2000 and at three levels of chromosomal band resolution (k). The reliability of the test was assessed by comparisons of the empirical and nominal α levels for each of the corresponding values of n and k. These analyses indicate that the sparse and discrete nature of chromosomal breakage data results in large and unpredictable discrepancies between the empirical and nominal α levels when fragile site identifications are based on small numbers of breaks (n < 0.5 k). With n≥ 0.5 k, the distribution of X _s ² appears to be stable and non-significant differences in the empirical and nominal α levels are generally obtained. These results are inherent to the nature of the data and are, therefore, relevant to any statistical model for the identification of fragile sites from chromosomal breakage data. For FSM identification of fragile sites at α = 0.05, we suggest that n≥ 0.5 k is the minimum reliable number of mapped chromosomal breaks per individual. Received: 28 April 1997 / Accepted: 1 July 1997     

The convergence in distribution of some simple epidemics

A group of n susceptible individuals exposed to a contagious disease isconsidered. It is assumed that at each point in time one or more susceptible individuals can contract the disease. The progress of this simple batch epidemic is modeled by a stochastic process X_n(t), t[0, ∞), representing the number of infectiveindividuals at time t. In this paper our analysis is restricted to simple batch epidemics with transition rates given by [α²X_n(t){n −X_n(t) +X_n(0)}]^1/2, t[0, ∞), α(0, ∞). This class of simple batch epidemics generalizes a model used and motivated by McNeil (1972) to describe simple epidemic situations. It is shown for this class of simple batch epidemics, that X_n(t), with suitable standardization, converges in distribution as n→∞ to a normal random variable for all t(0, t₀), and t₀ is evaluated.     

On the difference between gauss-markov and least squares estimates

For the usual full rank univariate least squares regression model y = XB + e, E(e) = 0, E(ee) = A, the equality of the estimates occurs when B-B^* = (XA^?1X)^?1XA^-1y-(XX)^?1Xy = 0. A necessary and sufficient condition for this equality is that A has some N - k + 1 roots equal where N is the rank of A and k is the rank of X.     

Interaction with Shelter Dogs Reduces Negative Affect of Adolescents in Substance Use Disorder Treatment

We investigated the effectiveness of a human–animal interaction program, involving dogs from an animal shelter, in improving affect of adolescent males in inpatient treatment for substance use disorder (SUD). We hypothesized that adolescents would experience improvements in affect and attitudes toward activities when participating in human–dog interaction activities (dog-interaction condition) compared with “treatment-as-is” recreational activities (control condition). Participants were assigned to weekly 1-h-long condition activities for 8 weeks (4 weeks per condition). Due to attrition, only the participants’ first and second exposures to each condition were evaluated. Using a withinand between-subjects, repeated measures crossover design, we assessed effects of the two conditions on affective states as indexed by Positive and Negative Affect Scale-Expanded Form (PANAS-X) subscales (mixed linear model, n = 12). Attitudes toward doginteraction and control activities were assessed using a researcher-generated survey (ordered logistic regression, n = 14, mean age = 16.2 years). Condition impacted Hostility (F_(1,31) = 6.55, p < 0.05) and Sadness (F_(1,41) = 4.62, p < 0.05) subscale scores; scores were higher following the control condition and lower following the dog-interaction condition. There was a carryover effect of condition in the previous activity session on Sadness scores during the current activity session (F_(1,41) = 4.32, p < 0.05), suggesting that the prior session experience affected current expectations. In the attitudes survey, the dog-interaction condition elicited more positive responses than the control condition (X² ≥ 4.10, df = 1, p < 0.05). From this exploratory study, we conclude that the dog-interaction activities induced an improvement in affect, specifically within dimensions of negative affect, and participants had a more favorable attitude toward the dog activities than the treatment-as-is activities. Offering activities involving interaction with shelter dogs thus shows promise as a useful method for restoring responsiveness to naturally reinforcing (non-substance-related) affective stimuli in adolescents with SUD.     

Increased BDNF levels and NTRK2 gene association suggest a disruption of BDNF/TrkB signaling in autism

The brain‐derived neurotrophic factor (BDNF), a neurotrophin fundamental for brain development and function, has previously been implicated in autism. In this study, the levels of BDNF in platelet‐rich plasma were compared between autistic and control children, and the role of two genetic factors that might regulate this neurotrophin and contribute to autism etiology, BDNF and NTRK2, was examined. We found that BDNF levels in autistic children (n = 146) were significantly higher (t = 6.82; P < 0.0001) than in control children (n = 50) and were positively correlated with platelet serotonin distribution (r = 0.22; P = 0.004). Heritability of BDNF was estimated at 30% and therefore candidate genes BDNF and NTRK2 were tested for association with BDNF level distribution in this sample, and with autism in 469 trio families. Genetic association analysis provided no evidence for BDNF or NTRK2 as major determinants of the abnormally increased BDNF levels in autistic children. A significant association with autism was uncovered for six single nucleotide polymorphisms (SNPs) [0.004 (Z_(1df) = 2.85) < P < 0.039 (Z_(1df) = 2.06)] and multiple haplotypes [5 × 10^?4(χ_(3df) = 17.77) < P < 0.042 (χ_(9df) = 17.450)] in the NTRK2 gene. These results do not withstand correction for multiple comparisons, however, reflect a trend toward association that supports a role of NTRK2 as a susceptibility factor for the disorder. Genetic variation in the BDNF gene had no impact on autism risk. By substantiating the previously observed increase in BDNF levels in autistic children in a larger patient set, and suggesting a genetic association between NTRK2 and autism, this study integrates evidence from multiple levels supporting the hypothesis that alterations in BDNF/tyrosine kinase B (TrkB) signaling contribute to an increased vulnerability to autism.     

A comparison of the reproductive ability of <Emphasis Type="Italic">Varroa destructor</Emphasis> (Mesostigmata:Varroidae) in worker and drone brood of Africanized honey bees (<Emphasis Type="Italic">Apis mellifera</Emphasis>)

Colony infestation by the parasitic mite, Varroa destructor is one of the most serious problems for beekeeping worldwide. In order to reproduce varroa females, enter worker or drone brood shortly before the cell is sealed. To test the hypothesis that, due to the preference of mites to invade drone brood to reproduce, a high proportion of the mite reproduction should occur in drone cells, a comparative study of mite reproductive rate in worker and drone brood of Africanized honey bees (AHB) was done for 370 mites. After determining the number, developmental stage and sex of the offspring in worker cells, the foundress female mite was immediately transferred into an uninfested drone cell. Mite fertility in single infested worker and drone brood cells was 76.5 and 79.3%, respectively. There was no difference between the groups (X ² = 0.78, P = 0.37). However, one of the most significant differences in mite reproduction was the higher percentage of mites producing viable offspring (cells that contain one live adult male and at least one adult female mite) in drone cells (38.1%) compared to worker cells (13.8%) (X ² = 55.4, P < 0.01). Furthermore, a high level of immature offspring occurred in worker cells and not in drone cells (X ² = 69, P < 0.01). Although no differences were found in the percentage of non-reproducing mites, more than 74% (n = 85) of the mites that did not reproduce in worker brood, produced offspring when they were transferred to drone brood.     

Ab initio Models for Six-Center Multiple Proton Exchange and Ion Pair Formation Assisted by Lewis Acids

High level ab initio and density functional calculations, extrapolated to QCISD(T)/6-311+G(3df,2p)//MP2/6-31+G^**+ZPE, reveal that cyclic ion pairs can form in the hydrogen bonded complexes of haloboric acids BH_nX_3-n–HX, X=F, Cl, with Lewis bases HX, H₂O, CH₃OH, and NH₃, even in isolation (e.g., in the gas phase). The intrinsic acidities (deprotonation energies) required for protonation of these bases with formation of gas phase ion pairs are calculated to be <295 kcal/mol for water, <301 kcal/mol for methanol, and <306 kcal/mol for ammonia; such values are common for acidic sites in zeolites. All gas phase ion pairs prefer symmetric bidentate or tridentate structures. In the other cases where hydrogen bonded complexes prevail, symmetric ion pair-like transition structures for multiple hydrogen exchange are computed.Supplementary material to this paper is available in electronic form at http://dx.doi.org/10.1007/s0089400060563     

Modifying the role of serotonergic 5‐HTTLPR and TPH2 variants on disulfiram treatment of cocaine addiction: a preliminary study

Disulfiram is a cocaine pharmacotherapy that may act through increasing serotonin, benefiting patients with genetically low serotonin transporter levels (5‐HTTLPR, S′ allele carriers) and low serotonin synthesis (TPH2, A allele carriers). We stabilized 71 cocaine and opioid co‐dependent patients on methadone for 2 weeks and randomized them into disulfiram and placebo groups for 10 weeks. We genotyped the SLC6A4 5‐HTTLPR (rs4795541, rs25531) and TPH2 1125A>T (rs4290270) variants and evaluated their role in moderating disulfiram treatment for cocaine dependence. Cocaine‐positive urines dropped from 78% to 54% for the disulfiram group and from 77% to 76% for the placebo group among the 5‐HTTLPR S′ allele carriers (F = 16.2; df = 1,301; P < 0.0001). TPH2 A allele carriers responded better to disulfiram than placebo (F = 16.0; df = 1,223; P < 0.0001). Patients with both an S′ allele and a TPH2 A allele reduced cocaine urines from 71% to 53% on disulfiram and had no change on placebo (F = 21.6; df = 1,185; P < 0.00001).     

Variability in survival and mortality of Acacia drepanolobium Sjøstedt following prescribed burning at Olpejeta Conservancy,Kenya

Mortalities to Acacia drepanolobium, a main item in the diet of the eastern black rhino (Diceros bicornis Michaeli) in Olpejeta conservancy, Kenya, are caused by three main factors: drought, browsers and fire. The effect of controlled fires on A. drepanolobium was examined by monitoring survival and growth in experimental plots before and after fire episodes between 2003 and 2007. Density, survival and growth in A. drepanolobium trees were compared eighteen months before and after burning. Tall trees were more likely to die from fire compared to short trees (R² = 0.575; df = 6; P = 0.048), while seedling densities increased after fire (χ² = 36.57; df = 1; P = 0.001). Even with increased seedling densities, burned areas attracted large numbers of seedling predators, lowering the possibility of seedling recruitment into adult, as mean seedling heights reduced significantly (ANOVA, F = 204.42; df = 1; P = 0.036). Fires also significantly lowered flowering (F = 346; df = 1; P < 0.05) in A. drepanolobium, thereby affecting fruit production. Although fires caused mortalities to adult A. drepanolobium, the most significant effect was tree reversals into seedling height class as trees resprouted. Although fire may increase browse biomass of A. drepanolobium available for black rhino, it is not an appropriate black rhino habitat management tool because burnt areas attract many seedling predators that lower seedling recruitment into adult trees.     

Estimation and Verification of Hypotheses in Some Zyskind-Martin Models with Missing Values

Several theorems on estimation and verification of linear hypotheses in some Zyskind-Martin (ZM) models are given. The assumptions are as follows. Let y = Xβ + e or (y, Xβ, σ²V) be a fixed model where y is a vector of n observations, X is a known matrix nXp with rank r(X) = r ≦ p < n, where p is a number of coordinates of the unknown parameter vector β, e is a random vector of errors with covariance matrix σ²V, where σ² is unknown scalar parameter, V is a known non-negative definite matrix such that R(X) ? R(V). Symbol R(A) denotes a vector space generated by columns of matrix A. The expected value of y is Xβ. In this paper four following Zyskind-Martin (ZM) models are considered: ZMd, ZMa, ZMc and ZMqd (definitions in sec. 1) when vector y y₁ y₂ involves a vector y₁ of m missing values and a vector y₂ with (n — m) observed values. A special transformation of ZM model gives again ZM model (cf. theorem 2.1). Ten properties of actual (ZMa) and complete (ZMc) Zyskind-Martin models with missing values (cf. theorem 2.2) test functions F are given in (2.11)) are presented. The third propriety constitutes a generalization of R. A. Fisher's rule from standard model (y, Xβ, σ²I) to ZM model. Estimation of vector y₁ (cf. 3.3) of vector β (cf. th. 3.2) and of scalar σ² (cf. th. 3.4) in actual ZMa model and in diagonal quasi-ZM model (ZMqd) are presented. Relation between y? ₁ and β is given in theorem 3.1. The results of section 2 are illustrated by numerical example in section 4.     

Intra‐lake stable isotope ratio variation in selected fish species and their possible carbon sources in Lake Kyoga (Uganda): implications for aquatic food web studies

The stable isotopes of nitrogen (δ¹⁵N) and carbon (δ¹³C) provide powerful tools for quantifying trophic relationships and carbon flow to consumers in food webs; however, the isotopic signatures of organisms vary within a lake. Assessment of carbon and nitrogen isotopic signatures in a suite of plants, invertebrates, and fishes in Lake Kyoga, indicated significant variation between two sites for δ¹³C (paired t = 6.305; df = 14, P < 0.001 and δ¹⁵N paired t = 1.292; df = 14; P < 0.05). The fish fauna in Bukungu was generally more ¹³C enriched (mean δ¹³C = –16.37 ± 1.64‰) than in Iyingo (mean δ¹³C = –20.80 ± 2.41‰) but more δ¹⁵N depleted (mean δ¹⁵N = 5.57 ± 0.71‰) than in Iyingo (mean δ¹⁵N = 6.92 ± 0.83‰). The simultaneous shifts in phytoplankton and consumer signatures confirmed phytoplankton as the major source of carbon for the food chain leading to fish. Limited sampling coverage within lakes may affect lake wide stable isotope signatures, and the same error is transferred into trophic position estimation. Consideration of potential intra‐lake spatial variability in isotope ratios and size is essential in evaluating the spatial and trophic structure of fish assemblages.