Smallest bitter taste receptor (T2Rs) gene repertoire in carnivores

Bitter taste reception is presumably associated with dietary selection,preventing animals from ingesting potentially harmful compounds.Accordingly,carnivores,who encounter these toxic substances less often,should have fewer genes associated with bitter taste reception compared with herbivores and omnivores.To investigate the genetic basis of bitter taste reception,we confirmed bitter taste receptor(T2R)genes previously found in the genome sequences of two herbivores(cow and horse),two omnivores(mouse and rat)and one carnivore(dog).We also identified,for the first time,the T2R repertoire from the genome of other four carnivore species(ferret,giant panda,polar bear and cat)and detected 17−20 bitter receptor genes from the five carnivore genomes,including 12−16 intact genes,0−1 partial but putatively functional genes,and 3−8 pseudogenes.Both the intact T2R genes and the total T2R gene number among carnivores were the smallest among the tested species,supporting earlier speculations that carnivores have fewer T2R genes,herbivores an intermediate number,and omnivores the largest T2R gene repertoire.To further explain the genetic basis for this disparity,we constructed a phylogenetic tree,which showed most of the T2R genes from the five carnivores were one-to-one orthologs across the tree,suggesting that carnivore T2Rs were conserved among mammals.Similarly,the small carnivore T2R family size was likely due to rare duplication events.Collectively,these results strengthen arguments for the connection between T2R gene family size,diet and habit.

Smallest bitter taste receptor (T2Rs) gene repertoire in carnivores

Bitter taste reception is presumably associated with dietary selection, preventing animals from ingesting potentially harmful compounds. Accordingly, carnivores, who encounter these toxic substances less often, should have fewer genes associated with bitter taste reception compared with herbivores and omnivores. To investigate the genetic basis of bitter taste reception, we confirmed bitter taste receptor （T2R） genes previously found in the genome sequences of two herbivores （cow and horse）, two omnivores （mouse and rat） and one carnivore （dog）. We also identified, for the first time, the T2R repertoire from the genome of other four carnivore species （ferret, giant panda, polar bear and cat） and detected 17-20 bitter receptor genes from the five carnivore genomes, including 12-16 intact genes, 0-1 partial but putatively functional genes, and 3-8 pseudogenes. Both the intact T2R genes and the total T2R gene number among carnivores were the smallest among the tested species, supporting earlier speculations that carnivores have fewer T2R genes, herbivores an intermediate number, and onmivores the largest T2R gene repertoire. To further explain the genetic basis for this disparity, we constructed a phylogenetic tree, which showed most of the T2R genes from the five carnivores were one-to-one orthologs across the tree, suggesting that carnivore T2Rs were conserved among mammals. Similarly, the small carnivore T2R family size was likely due to rare duplication events. Collectively, these results strengthen arguments for the connection between T2R gene family size, diet and habit.

Comparative evaluation of acute phase proteins by C-reactive protein(CRP)and serum amyloid A(SAA)in nonhuman primates and feline carnivores

The feasibility of a commercially available assay for C-reactive protein(CRP,CRP for humans:hCRP,and CRP for dogs:vCRP)and a trial reagent of serum amyloid A(SAA,vSAA for animals)were applied to the measurement of acute phase proteins in zoo animals,particularly in nonhuman primates and feline carnivores was evaluate.Results showed that hCRP and vSAA methods were applicable to measure CRP and SAA in Haplorhini.There was a highly signifcant correlation between both parameters with remarkably high correlation coefcient.A higher proportion of Bonnet macaques in Haplorhini,and the linear regression with good correlation between hCRP and vSAA levels were observed.Reference values in healthy Bonnet macaques were hCRP(46.86±30.97 nmol/L)and vSAA(9.06±1.95μg/mL).Although Ring-tailed lemur,which belonging to Strepsirrhini,showed low vSAA concentrations(reference values:1.08±0.47μg/mL),vSAA in patients was apparently elevated.The vCRP and vSAA methods were applicable to measurements of CRP and SAA in feline carnivores for highly signifcant correlation between both parameters.Theses two methods were also been deteded in lions,tigers and cheetahs.vSAA assays can be applied to measure SAA levels in other carnivores and herbivores.In conclusion,vSAA systems have potential utility as diagnostic tools for health screening and prediction in zoo animals.

Zoonosis Due to <i>Bruella suis</i>with Special Reference to Infection in Dogs (Carnivores): A Brief Review

Brucella suis (B. suis) is the major cause of porcine brucellosis. Zoonosis due to B. suis infection associated with transmission by various animal species is reported. Recently an increase in brucellosis associated with feral swine transmitted B. suis infection in humans and hunting dogs is emerging. Reports on B. suis infection in carnivores including dogs is scant. This report gives a brief review of B. suis zoonosis with particular reference to B. suis infection in dogs (carnivores).

Species identification refined by molecular scatology in a community of sympatric carnivores in Xinjiang, China

Many ecological studies and conservation management plans employ noninvasive scat sampling based on the assumption that species’ scats can be correctly identified in the field. However, in habitats with sympatric similarly sized carnivores, misidentification of scats is frequent and can lead to bias in research results. To address the scat identification dilemma, molecular scatology techniques have been developed to extract DNA from the donor cells present on the outer lining of the scat samples. A total of 100 samples were collected in the winter of 2009 and 2011 in Taxkorgan region of Xinjiang, China. DNA was extracted successfully from 88% of samples and genetic species identification showed that more than half the scats identified in the field as snow leopard（Panthera uncia） actually belonged to fox（Vulpes vulpes）. Correlation between scat characteristics and species were investigated, showing that diameter and dry weight of the scat were significantly different between the species. However it was not possible to define a precise range of values for each species because of extensive overlap between the morphological values. This preliminary study confirms that identification of snow leopard feces in the field is misleading. Research that relies upon scat samples to assess distribution or diet of the snow leopard should therefore employ molecular scatology techniques. These methods are financially accessible and employ relatively simple laboratory procedures that can give an indisputable response to species identification from scats.

Competitive interactions and coexistence of sympatric flagship carnivores in Asia

Understanding the competition and coexistence of flagship carnivores is key to creating strategies for their conservation in the face of global carnivore declines.Although studies exploring the dynamics and competition between tigers(Panthera tigris)and leopards(P.pardus)span decades,there is a lack of understanding regarding the factors that influence their coexistence mechanisms on a broad scale,as well as the drivers determining their exploitative and interference competition.We gathered a comprehensive list of research papers among which 36 papers explored the interspecific interactions between tigers and leopards and tested the influence of biotic and abiotic factors on the coexistence mechanisms along three dimensions using multiple response variables regression models;we also tested the influence of ecological drivers determining the exploitative or interference competition between tigers and leopards.Elevation and ungulate density were the most important predictors in regulating the coexistence mechanisms.Tigers and leopards exhibited more positive relations/higher overlaps as elevation increased in the spatial niche.In addition,they showed a higher dietary overlap in the prey-rich regions.We determined that interference competition between tigers and leopards was less frequently observed in habitats with dense tree cover and homogeneous vegetation structures.Meanwhile,studies with multiple metrics would promote the detection of interference competition.Our study provides new insight into the competitive interactions and coexistence mechanisms of tigers and leopards on a broad scale.Policy-makers and managers should pay more attention to the factors of elevation,prey abundance,and habitat structures for the conservation of tigers and leopards.

Multi-scale habitat selection and impacts of climate change on the distribution of four sympatric meso-carnivores using random forest algorithm

Background:The habitat resources are structured across different spatial scales in the environment,and thus animals perceive and select habitat resources at different spatial scales.Failure to adopt the scale-dependent framework in species habitat relationships may lead to biased inferences.Multi-scale species distribution models(SDMs)can thus improve the predictive ability as compared to single-scale approaches.This study outlines the importance of multi-scale modeling in assessing the species habitat relationships and may provide a methodological framework using a robust algorithm to model and predict habitat suitability maps(HSMs)for similar multi-species and multi-scale studies.Results:We used a supervised machine learning algorithm,random forest(RF),to assess the habitat relationships of Asiatic wildcat(Felis lybica ornata),jungle cat(Felis chaus),Indian fox(Vulpes bengalensis),and golden-jackal(Canis aureus)at ten spatial scales(500-5000 m)in human-dominated landscapes.We calculated out-of-bag(OOB)error rates of each predictor variable across ten scales to select the most influential spatial scale variables.The scale optimization(OOB rates)indicated that model performance was associated with variables at multiple spatial scales.The species occurrence tended to be related strongest to predictor variables at broader scales(5000 m).Multivariate RF models indicated landscape composition to be strong predictors of the Asiatic wildcat,jungle cat,and Indian fox occurrences.At the same time,topographic and climatic variables were the most important predictors determining the golden jackal distribution.Our models predicted range expansion in all four species under future climatic scenarios.Conclusions:Our results highlight the importance of using multiscale distribution models when predicting the distribution and species habitat relationships.The wide adaptability of meso-carnivores allows them to persist in human-dominated regions and may even thrive in disturbed habitats.These meso-carnivores are among the few species that may benefit from climate change.

An annotated checklist of mammals of Kenya

Kenya has a rich mammalian fauna. We reviewed recently published books and papers including the six volumes of Mammals of Africa to develop an up-to-date annotated checklist of all mammals recorded from Kenya. A total of 390 species have been identified in the country, including 106 species of rodents,104 species of bats, 63 species of even-toed ungulates(including whales and dolphins), 36 species of insectivores and carnivores, 19 species of primates,five species of elephant shrews, four species of hyraxes and odd-toed ungulates, three species of afrosoricids, pangolins, and hares, and one species of aardvark, elephant, sirenian and hedgehog. The number of species in this checklist is expected to increase with additional surveys and as the taxonomic status of small mammals(e.g., bats, shrews and rodents) becomes better understood.

Molecular epidemiological study of animal rabies in Kazakhstan

Rabies is a serious public health issue in Kazakhstan, with high economic impact and social burden. As part of a routine surveillance, 31 rabies-positive brain specimens taken from livestock(cattle) and carnivores(dogs, foxes, and cats)during 2013–2021 were subject to viral sequencing. Phylogenetic and Bayesian analysis were performed using obtained rabies virus(RABV) sequences. All 31 strains of RABV candidate belonged to the Cosmopolitan clade, of which 30strains belonged to steppe-type subclade, and 1 dog strain belonged to Other subclade. The 31 strains did not diverge from RABV strains in Kazakhstan and neighboring countries, including Russia, Mongolia, and China, suggesting that animal rabies has close relationship and transmission between borders. Fox-originated strains and cattle strains shared similar sequence signature, and some animal rabies cases had space–time intersection, showing that infected foxes were a major transmission source of cattle rabies in different Kazakhstan regions. Besides, free-roaming dogs played a pivotal role in rabies epizootics of cattle in Kazakhstan. The recent spread of animal rabies presents an increasing threat to public health, and provides updated information for improving current control and prevention strategies at the source for Kazakhstan and neighboring countries.

Occurrence and Some Ecological Aspects of the Golden Jackal (<i>Canis aureus</i>Linnaeus, 1758) in the Gaza Strip, Palestine

The Golden Jackal (Canis aureus Linnaeus, 1758), which belongs to the Canidae family, is an opportunist carnivore in the Gaza Strip (365 square kilometers). The current study aims at giving notes on the occurrence and some ecological aspects of the species in the Gaza Strip, Palestine. The study, which lasted 14 years (2007-2020), is descriptive and cumulative in its style. It was based on frequent field visits, direct observations and meetings and discussions with wildlife hunters, farmers and other stakeholders. The findings of the study show that Gazans are familiar with the Golden Jackal to the extent that a Gazan family holds the Arabic name of the animal, which is “Wawi”. The Golden Jackal was sometimes encountered and hunted in the eastern parts of the Gaza Strip, which are characterized by the presence of wilderness areas, intensive agriculture, poultry pens and solid waste landfills. Like other a few mammalian faunas, the adult Golden Jackals enter the Gaza Strip through gaps in or burrows beneath the metal borders separating the Gaza Strip from the rest of the Palestinian Territories and Egypt. Gaza zoos were found to harbor tens of Golden Jackals trapped or hunted by clever wildlife hunters using different means such as wire cages known locally as “maltash” and foothold traps with metal jaws that may cause lesions to the trapped animals. Poisoning and shooting were also common methods used to control the jackals and other carnivores causing harm to agriculture and livestock. The animal was known among the Gazans as an omnivore, feeding on wild and domestic animals in addition to plant materials, garbage and carrions. In conclusion, the study recommends the need to raise ecological awareness to preserve the Golden jackal and to adopt safe control measures for jackals and other carnivores, including the construction of protective fences for agricultural fields and animal pens.

New Record of Civets at Bharatpur, Chitwan and a Review of the Species Diversity in Nepal

Civets are alluring nocturnal carnivores having variant external features with different coat colors, stripes and spots, carpal and metatarsal pads, closed or open peri-anal scent glands in both sexes which have great taxonomic value and make these animals acclimatize in a wide range of geographical landscapes from hilly areas to patchy gardens and thin forests of the low land (Terai) located in or near the human settlement areas. The range of Head Body Length (HBL) and Tail Length (TL) in Paradoxurus spp. and Viverricula spp. distinguishes civets from felids. The study of civets was carried out by direct observation and videos and/or photographs were taken in the sighted places with the record of geological coordinates as evidence. For the record of civets, four wards (i.e. 7, 10, 11 and 12) were selected from Bharatpur Metropolitan City by lottery methods from the purposively selected 15 wards out of 29. These selected wards were visited randomly once or upon call in a month riding on a motorbike at the speed of 10 to 20 kilometer per hour in average speed and was crossed 2400 kilometers during four years beginning from January, 2016 to December, 2019. As a result, 11 civets of three Species, six Subspecies and two genera (i.e. Paradoxurus spp. and Viverricula spp.) were recorded. Among these animals, four subspecies were from Paradoxurinae and two were from Viverrinae subfamilies. Likewise, Paradoxurus jerdoni caniscus were reported, 9.09% (n = 1);Paradoxurus hermaphroditus minor, 9.09% (n = 1);Paradoxurus hermaphtoditus pallasii, 54.55% (n = 6);Paradoxurus hermaphroditus hermaphroditus, 9.09% (n = 1); Viverricula indica baptistae, 9.09% (n = 1);and Viverricula indica mayori, 9.09% (n = 1). Conclusively, the first records of the civet Species and Subspecies from thin gardens of fruiting trees and human houses or settlement areas in the city of Bharatpur, Chitwan, have created a great field to explore ecology and population status. However, human-civet conflicts have been created by the potential harm to poultry and pets as well as possible reservoir hosts of parasitic zoonoses and Covid-19 Viruses. Consequently, the population of civets is declining in an alarming rate due to the threats of vehicle and electric accidents, snaring and random killing by the people.

Studies on Feeding Habits and Parasitological Status of Red Fox, Golden Jackal, Wild Cat and Stone Marten in Sredna Gora, Bulgaria

In order to define the role of wild carnivores in the epidemiology of parasitoses with veterinary and medical importance their parasitological status and feeding habits were studied. In the period 2001-2006 the feeding habits of 167 foxes, 78 jackals, 40 wild cats and 23 stone martens from the area of Sredna Gora, Bulgaria were investigated. 113 of the foxes, 56 of the jackals, 22 of the wild cats and 21 of the martens were subjected to helminthological study. 147 wild boars and 26 badgers from the same area were subjected to trichinelloscopy. Rodents were the main food of the wild cats （82.7%）, martens （52%） and foxes （50%）. The main food of the jackals was carrion from domestic and wild animals （79.5%）. 95.5% of the foxes, 100% of the jackals, 95.5% of the wild cats and 89% of the stone martens were infected with one or more helminth species. The prevalence of the most important helminths： Trichinella spp., Taenia spp. and Ancylostoma spp. was high in all carnivores examined. In the infected with Trichinella spp. animals only T. britovi was demonstrated. The wild boars and badgers were not infected with Trichinella spp. The correlation between the feeding habits and parasitological status is discussed.

Evaluation of the suitability of a partially defatted black soldier fly (Hermetia illucens L.) larvae meal as ingredient for rainbow trout (Oncorhynchus mykiss Walbaum) diets

Background: Two trials were performed to evaluate a partially defatted Hermetia illucens(HI) larvae meal as potential feed ingredient in rainbow trout(Oncorhynchus mykiss Walbaum) diets. In the first trial, 360 trout(178.9 ± 9.8 g of mean initial body weight) were randomly divided into three experimental groups(4 tanks/treatment, 30 fish/tank). The fish were fed for 78 days with isonitrogenous, isolipidic and isoenergetic diets containing increasing levels of HI, on as fed basis: 0%(HI0, control diet), 25%(HI25) and 50%(HI50) of fish meal substitution, corresponding to dietary inclusion levels of 0, 20% and 40%. In the second trial, 36 trout(4 tanks/treatment, 3 fish/tank) were used to evaluate the in vivo apparent digestibility coefficients(ADC) of the same diets used in the first trial.Results: Survival, growth performance, condition factor, somatic indexes, and dorsal fillet physical quality parameters were not affected by diet. The highest dietary inclusion of HI larvae meal increased dry matter and ether extract contents of trout dorsal fillet. The use of HI larvae meal induced a decrease of valuable polyunsaturated fatty acids(PUFA) even if differences were only reported at the highest level of HI inclusion. The insect meal worsened the lipids health indexes of the same muscle. Dietary inclusion of insect meal did not alter the villus height of the fish. No differences were found among treatments in relation to ADC of ether extract and gross energy, while ADC of dry matter and crude protein were higher in HI25 if compared to HI50.Conclusions: The obtained results showed that a partially defatted HI larvae meal can be used as feed ingredient in trout diets up to 40% of inclusion level without impacting survival, growth performance, condition factor, somatic indexes, dorsal fillet physical quality parameters, and intestinal morphology of the fish. However, further investigations on specific feeding strategies and diet formulations are needed to limit the observed negative effects of the insect meal on the FA composition of dorsal muscle.

Human-wildlife conflict:A bibliometric analysis during 1991–2023

The escalating conflict between human and wildlife due to competing demands for limited space and resources has raised concerns worldwide,and understanding the dynamics of this conflict is crucial for devising effective strategies and policies.The present study is an attempt to carry out a bibliometric analysis of the published literature on the topic of human-wildlife conflict(HWC)for the period of January 1991–February 2023.For carrying out the analysis of the data obtained from Web of Science,the‘Bibliometrix'tool,developed through the R programming language,was used.The findings of the study revealed that a total of 1592 documents have been published on the HWC research topic from January 1991 to February 2023 within 338 sources.It is observed that the number of publications has continuously increased since 1991,with an annual growth rate of 5.16%.A total of 4995 authors have contributed to the targeted research field.Of the 388 sources,the journal‘Biological Conservation'is the most relevant and productive,followed by‘Oryx'and‘Human Dimensions of Wildlife'.Based on the country production analysis,authors from 110 countries have contributed to the field,and the USA has the highest frequency of publications on HWC,followed by the UK and Australia.The USA also has the highest multiple country publications and has collaborated with 88 countries,with the highest frequency of collaboration with the UK,followed by India,Australia,and South Africa.The most frequently used keywords include‘human-wildlife conflict',‘conservation',‘conflict',‘human-wildlife',‘wildlife',‘wildlife management',‘livestock',‘management',‘coexistence',and‘carnivore'.The present study identifies the most prolific authors,sources,institutions,and countries,as well as the study hotspots in the subject of HWC,which may assist researchers in finding the best working and publication platforms.Further,it may also help them identify reliable research partners to acquire the best findings and develop more effective strategies and policies to address the issue.

基于CPA-OSELM的热轧带钢厚度在线预测

为解决自动厚度控制(automatic gauge control, AGC)系统反馈滞后、耦合强、厚度偏差大等问题,提出了一种基于食肉植物算法(carnivorous plant algorithm, CPA)的在线顺序极限学习机(online sequential extreme learning machine, OSELM)预测算法。首先,基于从现场采集的相关数据,建立了OSELM在线厚度预测模型。然后为了提高模型的准确性及稳定性,采用CPA方法优化OSELM的权重和偏置。在此基础上,运用自学习方法进一步提高模型的预测精度。最后,通过实验验证基于CPA-OSELM预测模型的有效性。实验结果表明:基于CPA-OSELM的方法能够对不同规格带钢的出口厚度进行高精度在线预测,预测结果可用于提升AGC模型的控制精度,为提升带钢产品质量奠定基础。

Impacts of Norwegian large carnivore management strategy on national grazing sector

Increasing populations of large carnivores are leading to tension and conflicts with livestock production,a situation that potentially might escalate.In Norway the objective of the large carnivore policy is two-folded:to ensure viable carnivore populations and to secure a sustainable grazing industry.The main instrument is zonation,with carnivore management zones(CMZs)prioritized for reproduction of the large carnivore species separated from other areas prioritized for grazing livestock.The objective of this paper is to describe current knowledge about the impact of the zoning management strategy on the grazing industry.This is done by documenting status and changes in sheep production,losses of livestock to predating carnivores,and the use of grazing areas inside and outside the CMZs.CMZsoffering protection for lynx,wolverine,bear and wolf cover 55%of the Norwegian mainland.30%of the sheep and 50%of the Sami reindeer grazing areas are found inside the CMZs.Livestock(semi-domestic reindeer excluded)is using 59%of the available natural pasture areas outside the CMZs,but only 26%inside the CMZs.The lowest use of available grazing areas was found inside zones for wolves(12%)and brown bears(6%).Livestock in these zones are confined to fenced enclosures,mostly on the farm itself,or moved to pastures outside the management zone for summer grazing.Livestock losses increased in the affected regions during the period when carnivores were reestablished.Later,losses declined when CMZs were established and mitigation efforts were implemented in these zones.The bulk of sheep and reindeer killed by carnivores are now found in boundary areas within 50 km off the CMZs,where sheep are still grazing on open mountain and forest ranges.Therefore,instruments to protect livestock in areas close to the CMZs are also needed.The number of sheep declined inside the CMZs from 1999 to 2014,but increased outside the zones.The reduction in the absolute number of sheep in the CMZs is balanced by a similar increase outside,thus the total sheep production in Norway is maintained.We conclude that although of little consequence for the total food production in Norway,the economic and social impact of the large carnivore management strategy can be serious for local communities and individual farmers who are affected.There is a need for more exact carnivore population monitoring to quantify the carnivore pressure,better documentation of reindeer losses,and a clearer and stricter practicing of the zoning strategy.Increased involvement of social sciences is important in order to understand the human dimension of the carnivore conflicts.

Patterns of δ^(13) C and δ^(15) N in wolverine Gulo gulo tissues from the Brooks Range,Alaska

Knowledge of carnivore diets is essential to understand how carnivore populations respond demographically to variations in prey abundance. Analysis of stable isotopes is a useful complement to traditional methods of analyzing carnivore diets. We used data on δ^13C and δ^15N in wolverine tissues to investigate patterns of seasonal and annual diet variation in a wolverine Gulo gulo population in the western Brooks Range, Alaska, USA. The stable isotope ratios in wolverine tissues generally reflected that of terrestrial carnivores, corroborating previous diet studies on wolverines. We also found variation in δ^13C and δ^15N both between muscle samples collected over several years and between tissues with different assimilation rates, even after correcting for isotopic fractionation. This suggests both annual and seasonal diet variation. Our results indicate that data on δ^13C and δ^15N holds promise for qualitative assessments of wolverine diet changes over time. Such temporal variation may be important indicators of ecological responses to environmental perturbations, and we suggest that more refined studies of stable isotopes may be an important tool when studying temporal change in diets of wolverines and similar carnivores [ Current Zoology 55 （3）： 188- 192, 2009].

A Medical Hypothesis: Excessive Adaptation Results in Relative Hypothermia and Lymphocytopenia, as Seen in Carnivorous Aquatic Mammals

Body temperature is an important clinical indicator of health and illness. Many studies of human body temperature have been conducted;however, there are no studies that compare the body temperatures of humans and other homeothermic animals. Twenty-six homeothermic animal species, including humans, were selected and characteristics of their internal environment were studied based on previous reports. The studied species were divided into two groups based on habitat (eight aquatic and eighteen terrestrial species) and three groups based on diet (carnivores, herbivores, and omnivores). Body temperatures, erythrocyte counts, and lymphocyte percentages were compared between species and between groups. Our results showed that carnivores had lower body temperatures and erythrocyte numbers than herbivores, and lower lymphocyte ratios than both herbivores and omnivores. Aquatic mammals that experienced a second adaptation event during their evolutionary process had lower body temperatures and lymphocyte ratios than terrestrial animals. These results suggest that excessive adaptation induced by stress or a change in environment may result in relative hypothermia and lymphocytopenia, features that aquatic mammals with stressful evolutionary backgrounds share with human cancer patients. However, our study is based on analysis of previous observations and reports, and further research (e.g., larger-scale studies) is needed to support this hypothesis.

The Ecological Balance of the Fish Community in an Aging Reservoir

Reservoir fishes contribute significantly to freshwater fish resources in Nigeria. The composition, size variation and relative abundance of fishes in Opa reservoir, Southwest Nigeria, were investigated to establish the ecological balance of the various trophic groups of fishes in the reservoir. The study was carried out in view of recent reports on the decline in the quality and quantity of water in the aging reservoir. Fishes were collected from the reservoir monthly for twelve months using monofilament gill nets and wire cages.? The fishes were identified to species level and the ecological balance of the fish community was calculated as a ratio of the forage to the carnivore groups by number and by weight. Data were subjected to statistical analysis using the Stata 13 software. 1915 fishes belonging to 17 species and 10 families were collected from the reservoir. The fish composition was dominated by the family cichlidae, with its 7 species accounting for 89.8% of the total catch. There were 2 species of clariidae, which made 6.2% of the total catch. The ecological balance of the fish community was 3.4 (by number) and 6.2 (by weight). The result obtained revealed that the fish community in the reservoir is ecologically balanced.Comparative analysis of the fish composition of the Opa reservoir with reports from other reservoirs in Southwest Nigeria showed that the reservoir has more fish species than most of the other reservoirs around. The study concludes that the reservoir still supports a rich, diverse and ecologically balanced fish community. It is recommended that the management of these fish resources should be key in the holistic management of the aging Opa reservoir.

Shift in microhabitat use as a mechanism allowing the coexistence of victim and killer carnivore predators

It has been suggested that spatial heterogeneity is key to the coexistence at local spatial scales of subordinate and dominant predator species by allowing the former to shift to more protective habitats when the risk of intraguild predation exists. Here, we show how the smaller carnivore Egyptian mongoose (Herpestes ichneumon) may coexist on a local scale with its intraguild pre- dator, the Iberian lynx (Lynx pardinus), by using places with different microhabitat character- istics. We expect that mongooses living within lynx home ranges will use denser and more protective habitats when active in order to di- minish their risk of being killed by lynx com- pared to those living in areas similar in vege- tation and prey availability but where lynx are absent. The scrubland cover of points used by mongooses outside lynx areas, and that of points located within lynx areas but not used by mongooses, were significantly lower than, or similar to, cover of points used by mongooses within lynx areas. The probability of finding mon- goose tracks was constant across levels of scrubland cover when lynx were absent, but more mongoose tracks were likely to be found in thicker scrubland within lynx areas, especially if these areas were intensively used by lynx. This result agrees with the hypothesis on shifts in microhabitat use of subordinate carnivores to prevent fatal or risky encounters with dominant ones.