المؤلفون: Chengxu Ha¹, Yunzhong Wang² xyz9949@163.com, Cuihua Yang¹, Peng Jin¹, Yi Ren¹

المصدر: Israeli Journal of Aquaculture-Bamidgeh. 2024, Vol. 76 Issue 2, p1-8. 8p.

مصطلحات موضوعية: *CICHLIDS, *FISH microbiology, *FISH feeds, *FISH growth, *DNA sequencing

مستخلص: The electric yellow cichlid (Labidochromis caeruleus), renowned for its exceptional ornamental value, enjoys widespread popularity among aquarium enthusiasts and holds significant economic value in the market. This study employed high-throughput sequencing technology to analyze the microorganisms in the circulating water of the electric yellow cichlid cultivated with six different types of feeds. Statistical results showed that the compound feed group exhibited the highest specific growth and mass gain rates. In contrast, the water flea and brine shrimp groups showed lower rankings with significant differences. 51,084 to 64,626 effective sequences were obtained and clustered into 127 to 848 operational taxonomic units (OTUs). The research findings indicate a remarkable bacterial diversity in the breeding environment of electric yellow cichlids with higher levels in the water flea and brine shrimp groups, and the lowest level in the compound feed group; the dominant bacterial phyla in all six experimental groups include Proteobacteria, Actinobacteria, Parcubacteria, and Cyanobacteria; Comparative analysis using the COGs database revealed significant differences (P<0.05) in the metabolic pathways of 24 functional microbial genes among the experimental groups. [ABSTRACT FROM AUTHOR]

المؤلفون: Paiz, Leonardo Marcel^1,2 (AUTHOR), Gavazzoni, Mariane¹ (AUTHOR), Antoniazi, Gabrielle Jovana¹ (AUTHOR), Baumgärtner, Lucas¹ (AUTHOR), da Graça, Weferson Júnio^2,3 (AUTHOR), Feldberg, Eliana⁴ (AUTHOR), Lui, Roberto Laridondo¹ (AUTHOR), Margarido, Vladimir Pavan^1,2 (AUTHOR) Vladimir.Margarido@unioeste.br

المصدر: Reviews in Fish Biology & Fisheries. Jun2024, Vol. 34 Issue 2, p849-866. 18p.

مصطلحات موضوعية: *CHROMOSOMES, *CICHLIDS, *CYTOGENETICS, *WATERSHEDS, *RECOMBINANT DNA

مصطلحات جغرافية: PARANA (Brazil : State)

مستخلص: Comprising more than 100 species, Crenicichlina encompasses 20% of the taxonomic diversity of Neotropical cichlids and is widely distributed throughout Brazilian watersheds. A new hypothesis about the phylogeny of pike cichlids has recently been proposed, based on morphological and molecular characters, and new genera were created. We analyzed 18 species of four genera of Crenicichlina, collected in the Amazon, Iguaçu, Paraná and Uruguay River basins, using conventional and molecular cytogenetics. We present new cytogenetic data for nine species of pike cichlid, the chromosomal mapping of 5S rDNA for Crenicichla and other three species (Lugubria cincta, L. lugubris and Saxatilia semicincta), including available review of cytogenetic studies in Crenicichlina. Cytogenetic data for Crenicichla show a conserved cytotaxonomic pattern for most of the analyzed species: single 5S and 18S rDNA sites always in interstitial position centromeric heterochromatin. Lugubria showed greater variation in chromosomal characters, mainly an increase in 18S rDNA sites, always in terminal position and associated with heterochromatin. On the other hand, Saxatilia showed the same 18S rDNA pattern as Crenicichla, but with the presence of multiple 5S rDNA sites. Finally, karyotype of one species of Wallaciia that was analyzed possessed single 5S rDNA sites and multiple NORs. Although some chromosomal characters are conserved in Cichlinae, interspecific differences were verified in the karyotypic composition, as possible intragenus patterns. Chromosomal characters, mainly 5S and 18S rDNA, proved to diagnose species as well as they contribute to phylogenetic studies in pike cichlids. [ABSTRACT FROM AUTHOR]

المؤلفون: Popoola, Omoniyi Michael¹ (AUTHOR) ompopoola@futa.edu.ng

المصدر: Croatian Journal of Fisheries. Jun2024, Vol. 82 Issue 2, p49-55. 7p.

مصطلحات موضوعية: *NILE tilapia, *CICHLIDS, *GENETIC variation, *CYTOCHROME b, *FISH farming, *MARINE parks & reserves, *WHALE watching

مستخلص: Nile tilapia Oreochromis niloticus is one of the most important fishery resources and a valuable fish species for aquaculture programmes. It is found in almost all waters and is widely dispersed. Several natural populations of this species have been impacted by genetic pollution despite their significant economic relevance. Understanding population structure is a crucial first step in protecting this species in its native habitats as well as in choosing which wild stocks to use in hatchery initiatives. To demonstrate the genetic-population structure of this species, genetic differences among three geographically secluded populations of O. niloticus were investigated utilizing mitochondrial DNA cytochrome b gene sequences. The results were used to estimate the levels of genetic variability within and among the populations. The 56 cyt b (821 bp) sequences analysis revealed 21 haplotypes, with a nucleotide diversity of 0.0510 and a haplotype diversity of 0.881. In each of the populations, seven (7) singleton variable sites and 19 informative-parsimony sites, genetic diversity could be identified and few population haplotypes were found, indicating a minor genetic distinction between them. For the purpose of conservation and/or Nile tilapia breeding programmes, this information would assist in choosing the fish populations that maintain greater genetic variation in O. niloticus. [ABSTRACT FROM AUTHOR]

المؤلفون: Bertinetti, César^1,2 (AUTHOR), Härer, Andreas¹ (AUTHOR), Karagic, Nidal¹ (AUTHOR), Meyer, Axel¹ (AUTHOR), Torres-Dowdall, Julián^1,2 (AUTHOR) torresdowdall@nd.edu

المصدر: American Naturalist. May2024, Vol. 203 Issue 5, p604-617. 14p.

مصطلحات موضوعية: *CRATER lakes, *CICHLIDS, *ADAPTIVE radiation, *GENE expression, *PHENOTYPIC plasticity, *HATCHERY fishes

مستخلص: Selection pressures differ along environmental gradients, and traits tightly linked to fitness (e.g., the visual system) are expected to track such variation. Along gradients, adaptation to local conditions might be due to heritable and nonheritable environmentally induced variation. Disentangling these sources of phenotypic variation requires studying closely related populations in nature and in the laboratory. The Nicaraguan lakes represent an environmental gradient in photic conditions from clear crater lakes to very turbid great lakes. From two old, turbid great lakes, Midas cichlid fish (Amphilophus cf. citrinellus) independently colonized seven isolated crater lakes of varying light conditions, resulting in a small adaptive radiation. We estimated variation in visual sensitivities along this photic gradient by measuring cone opsin gene expression among lake populations. Visual sensitivities observed in all seven derived crater lake populations shifted predictably in direction and magnitude, repeatedly mirroring changes in photic conditions. Comparing wild-caught and laboratory-reared fish revealed that 48% of this phenotypic variation is genetically determined and evolved rapidly. Decreasing intrapopulation variation as environments become spectrally narrower suggests that different selective landscapes operate along the gradient. We conclude that the power to predict phenotypic evolution along gradients depends on both the magnitude of environmental change and the selective landscape shape. [ABSTRACT FROM AUTHOR]

المؤلفون: Aranda, Dejanira¹ (AUTHOR), Arce, Elsah² (AUTHOR) elsah.arce@uaem.mx, Mercado‐Silva, Norman³ (AUTHOR), Burciaga, Luis M.⁴ (AUTHOR)

المصدر: Ethology. May2024, Vol. 130 Issue 5, p1-9. 9p.

مصطلحات موضوعية: *CICHLIDS, *CONTESTS, *AGGRESSION (Psychology), *ANIMAL fighting, *NATIVE species, *BODY size

مستخلص: In animal fights, there are often size asymmetries between opponents. Although larger individuals typically dominate smaller ones, size is not the sole determining factor, as the competitors' motivation, aggressiveness, resource value, physiological characteristics, and strength also play crucial roles in fighting outcomes. In this study, we evaluated the influence of body size on dominance hierarchy and contest success during intra‐ and inter‐specific contests in two fish species: the native mojarra of the Balsas basin Amphilophus istlanus and the invasive convict cichlid Amatitlania nigrofasciata. We used size‐asymmetric males to carry out experimental contests. The number and type of aggressive behaviors, time to contest outcome, and dominant individual at the end of the contest were determined. In contests between two native mojarra, the smaller individual always lost. In contests between convict cichlids, the smaller contestants lost in all contests where size asymmetry was greater than 20%. In interspecific contests, the native mojarra performed more aggressive behaviors than the invasive convict cichlid and dominated convict cichlids despite a size disadvantage. This suggests that in terms of competition via interference, the native mojarra can counter the arrival of the invasive convict cichlid. [ABSTRACT FROM AUTHOR]

المؤلفون: Hidaka, Ryo^1,2 (AUTHOR) h.r.s.k.0330@gmail.com, Sogawa, Shumpei^1,2 (AUTHOR) a10se013@yahoo.co.jp, Kohda, Masanori^1,2 (AUTHOR), Awata, Satoshi^1,2 (AUTHOR)

المصدر: Animal Behaviour. May2024, Vol. 211, p99-109. 11p.

مصطلحات موضوعية: *PUNISHMENT (Psychology), *CICHLIDS, *ANIMAL breeding, *PUNISHMENT, *FISH breeding

مستخلص: Prosocial punishment is a process of enforcement that promotes a partner's cooperation in a sustained relationship and is an important mechanism in the evolution of cooperative behaviour. The 'pay-to-stay' hypothesis predicts that in cooperatively breeding animals, dominant breeders punish idle subordinates (helpers) that assist breeders in offspring care to promote their cooperation. However, limited evidence demonstrates that subordinates increase helping effort in response to breeder aggression; therefore, whether breeder aggression functions as punishment remains unclear. In the laboratory, we observed idle helpers of the cooperatively breeding cichlid fish Neolamprologus savoryi and whether dominant breeders punished them. Breeders increased their aggression towards subordinates that were prevented from helping by 2 h removal from the tank, and attacked helpers subsequently increased territorial defence depending on breeder aggression level, suggesting that breeder aggression functions as punishment. No breeder aggression was observed when helpers performed pre-emptive helping behaviour prior to dominant breeder attacks. Notably, dominant breeders punished even their offspring when idle, suggesting that the helping behaviours of relatives may be facilitated by parental punishment. Our study shows that dominant group members can use punishment to elicit help from subordinates, even in nonhuman animals. • We tested whether dominant breeders punish idle helpers in Neolamprologus savoryi. • Breeders increased their aggression towards helpers prevented from helping. • The helpers that were attacked by the breeders increased territorial defence. • Pre-emptive helping by subordinates may function as pre-emptive appeasement. • Dominant breeders can use punishment to elicit help from subordinates even in fish. [ABSTRACT FROM AUTHOR]

المؤلفون: Guadagno, Angelo¹ (AUTHOR) angelo.guadagno@unibe.ch, Triki, Zegni¹ (AUTHOR) zegni.triki@gmail.com

المصدر: Brain & Behavior. May2024, Vol. 14 Issue 5, p1-11. 11p.

مصطلحات موضوعية: *COGNITIVE testing, *CICHLIDS, *MORPHOLOGY, *COGNITIVE flexibility, *SOCIAL status, *EXECUTIVE function

مستخلص: Background: Living in a social dominance hierarchy presents different benefits and challenges for dominant and subordinate males and females, which might in turn affect their cognitive needs. Despite the extensive research on social dominance in group‐living species, there is still a knowledge gap regarding how social status impacts brain morphology and cognitive abilities. Methods: Here, we tested male and female dominants and subordinates of Neolamprologus pulcher, a social cichlid fish species with size‐based hierarchy. We ran three executive cognitive function tests for cognitive flexibility (reversal learning test), self‐control (detour test), and working memory (object permanence test), followed by brain and brain region size measurements. Results: Performance was not influenced by social status or sex. However, dominants exhibited a brain–body slope that was relatively steeper than that of subordinates. Furthermore, individual performance in reversal learning and detour tests correlated with brain morphology, with some trade‐offs among major brain regions like telencephalon, cerebellum, and optic tectum. Conclusion: As individuals' brain growth strategies varied depending on social status without affecting executive functions, the different associated challenges might yield a potential effect on social cognition instead. Overall, the findings highlight the importance of studying the individual and not just species to understand better how the individual's ecology might shape its brain and cognition. [ABSTRACT FROM AUTHOR]

المؤلفون: Sommer-Trembo, Carolin¹ carolin.sommer-trembo@unibas.ch, Santos, M. Emília², Clark, Bethan, Werner, Marco³, Fages, Antoine, Matschiner, Michael⁴, Hornung, Simon, Ronco, Fabrizia, Oliver, Chantal, Garcia, Cody, Tschopp, Patrick, Malinsky, Milan⁵ milan.malinsky@unibe.ch, Salzburger, Walter walter.salzburger@ unibas.ch

المصدر: Science. 4/26/2024, Vol. 384 Issue 6694, p470-475. 6p. 3 Diagrams.

مصطلحات موضوعية: *ADAPTIVE radiation, *CICHLIDS, *CURIOSITY, *REGULATOR genes, *SINGLE nucleotide polymorphisms, *BEHAVIOR genetics, *GENOME editing

مستخلص: Behavior is critical for animal survival and reproduction, and possibly for diversification and evolutionary radiation. However, the genetics behind adaptive variation in behavior are poorly understood. In this work, we examined a fundamental and widespread behavioral trait, exploratory behavior, in one of the largest adaptive radiations on Earth, the cichlid fishes of Lake Tanganyika. By integrating quantitative behavioral data from 57 cichlid species (702 wild-caught individuals) with high-resolution ecomorphological and genomic information, we show that exploratory behavior is linked to macrohabitat niche adaptations in Tanganyikan cichlids. Furthermore, we uncovered a correlation between the genotypes at a single-nucleotide polymorphism upstream of the AMPA glutamate-receptor regulatory gene cacng5b and variation in exploratory tendency. We validated this association using behavioral predictions with a neural network approach and CRISPR-Cas9 genome editing. [ABSTRACT FROM AUTHOR]

المؤلفون: Piesiewicz, Radosław¹ (AUTHOR) jaszko.krzystolik@gmail.com, Krzystolik, Jan¹ (AUTHOR), Korzelecka-Orkisz, Agata¹ (AUTHOR), Tański, Adam¹ (AUTHOR), Formicki, Krzysztof¹ (AUTHOR)

المصدر: Animals (2076-2615). Apr2024, Vol. 14 Issue 8, p1238. 19p.

مصطلحات موضوعية: *CICHLIDS, *YOLK sac, *EMBRYOLOGY, *FISH breeding, *EGGS, *FISH development, *SPECIES, *ONTOGENY

الشركة/الكيان: CARL Zeiss AG , NIKON Inc.

مستخلص: Simple Summary: The aim of this study was to provide a detailed characterization of the reproductive strategy, embryonic development, and larval development of three fish species from the genus Cichlasoma: the green terror (Andinoacara rivulatus), the red discus (Symphysodon discus), and the jaguar cichlid (Parachromis managuensis). Eggs for the study were obtained from five pairs of each species (300 eggs from each female) and incubated at 26 °C. Developing eggs were observed from fertilization to larval hatching, up to the complete absorption of the yolk sac. The results of the study will contribute to the development of reproductive biotechnology for the studied fish, enabling effective and easy breeding of these fish under controlled conditions. This will not only meet the demand for these species in the aquarium trade but also protect them in their natural habitat by discontinuing fishing activities. The purpose of this study was to characterize in detail the reproductive strategy, course of embryogenesis, and development of larvae in three species of fishes of the genus Cichlasoma: the green terror (Andinoacara rivulatus), the red discus (Symphysodon discus), and the jaguar cichlid (Parachromis managuensis). Eggs for the study were obtained from five pairs of each species (300 eggs from each female) and incubated at 26 °C. The developing eggs were observed under a microscope (Carl Zeiss Stereo Discovery. V12 and Nikon 2000SE software (NIS-Elements F 4.30.01 64-bit) from fertilization to larval hatching until complete yolk-sac resorption. The largest average number of eggs per female was found in the jaguar cichlid ( x ¯ = 2991 eggs), a smaller average number of eggs was shown in the green terror ( x ¯ = 922 eggs), and the red discus showed the smallest average number of eggs ( x ¯ = 300 eggs). There were significant differences in the sizes of the eggs of the studied species: jaguar cichlid eggs were the smallest (1.060 ± 0.05 mm3), red discus eggs were larger (1.070 ± 0.07 mm3), and green terror eggs were the largest (1.365 ± 0.16 mm3). The embryogenesis time in the red discus was 2132 °H (82 Hpf), in the green terror it was 2158 °H (83 Hpf), and the longest in the jaguar cichlid was 2470 °H (87 Hpf). At the end of embryogenesis, the average size of the larvae after hatching was measured (red discus x ¯ = 4.346 mm, green terror x ¯ = 5.203 mm, and jaguar cichlid x ¯ = 5.301 mm) and the time of yolk-sac resorption from the moment of hatching to the transition from endogenous to exogenous feeding was determined (jaguar cichlid 5 days, green terror 6 days, and red discus 3 days). The results of this study may contribute to the development of reproductive biotechnology for the studied fishes that could be used in aquaculture and, thus, help protect them in their natural habitats. [ABSTRACT FROM AUTHOR]

المؤلفون: Caroline de Oliveira, Rianne^1,2 rianne.oliveira@gmail.com, Caserta Tencatt, Luiz Fernando³ luiztencatt@hotmail.com, de Carvalho Deprá, Gabriel¹ gabrieldepra@gmail.com, Britzke, Ricardo⁴ rbritzke@unmsm.edu.pe, Oliveira, Claudio⁵ claudio.oliveira@unesp.br, Júnio da Graça, Weferson^1,2,6 weferson@nupelia.uem.br

المصدر: Neotropical Ichthyology. 2024, Vol. 22 Issue 2, p1-26. 26p.

مصطلحات موضوعية: *CICHLIDS, *MAXILLA, *MANDIBLE, *SPECIES, *GENETIC barcoding

مصطلحات جغرافية: BRAZIL

الملخص (بالإنجليزية): Morphological and molecular data support the description of a new Aequidens species from the upper rio Correntes, considered herein as endemic to the upper rio Paraguai basin in the Cerrado biome in Brazil. The new species is distinguished from all congeners, except from A. plagiozonatus by having anteriorly oblique dark brown flank bars vs. vertical flank bars, and is additionally distinguished from some congeners by showing a discontinuous lateral band and presence of a dark cheek spot. The new species differs from Aequidens plagiozonatus by having the profile of the dorsal part of head almost straight (in lateral view), with a conspicuous concavity at the interorbital, and by the longer length of upper and lower jaws. Furthermore, delimitation analyses based on mitochondrial data provide additional support for the validity of the species. Our study data also revealed the occurrence, and consequently the first record, of A. plagiozonatus in the upper rio Araguaia basin, which was most likely driven by headwater capture events. [ABSTRACT FROM AUTHOR]

Abstract (Portuguese): Dados morfológicos e moleculares apoiam a descrição de uma nova espécie de Aequidens do alto rio Correntes, considerada aqui como uma espécie endêmica da bacia do alto rio Paraguai, no bioma Cerrado no Brasil. A nova espécie distinguese de todas as congêneres, exceto de Aequidens plagiozonatus, por apresentar barras laterais marrom-escuras oblíquas em direção anterodorsal vs. barras verticais nos flancos. Além disso, distingue-se de algumas espécies por apresentar uma faixa lateral descontínua e pela presença de uma mancha escura na porção entre a órbita e a margem preopercular. A nova espécie difere de A. plagiozonatus por apresentar o perfil da parte dorsal da cabeça (em vista lateral) aproximadamente reta, com uma concavidade conspícua na porção interorbital, e pelo maior comprimento das maxilas superior e inferior. Além disso, análises de delimitação baseadas em dados mitocondriais oferecem evidência a favor da validade da espécie. Nossos dados também revelaram a ocorrência e, consequentemente, o primeiro registro de A. plagiozonatus na bacia do alto rio Araguaia, provavelmente devido a eventos de captura de cabeceiras. [ABSTRACT FROM AUTHOR]