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# Abundance and Micro-Distribution of Cichlid Fishes on a Rocky Shore of Lake Tanganyika

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Every species of rock dwelling cichlid fishes were counted with help of SCUBA at Luhanga in the northwestern part of Lake Tanganyika in 1980. In this area rocky substrate was prominent especially in shallow bottom, while stone, rubble, gravel or sandy substrates were patchily scattered among rocks. About 7,000 fishes of 38 species were counted in a quadrat (20x20 m &sup2;). Plankton feeders (2 species) were most abundant (56%), omnivores (7 species) and Aufwuchs eater (15 species) composed of 21 and 18%, respectively. Numbers of zoobenthos feeders (8 species) and piscivores including scale eaters (6 species) were about 4%. Plankton feeders were gregarious, while species of the other feeding habits were exclusively distributed to other conspecific individuals. About a half number of species frequented on a specific substrate type as follows: Almost all Aufwucks eaters preferred strongly on rocks especially in shallow water layer and zoobenthos feeders had different preferences to substrate each other, showing repulsive distribution. Among another half number of species, 3 species adhered to shallow region and the rest species showed ubiquitous distribution without any substrate preference, and their number of individuals was small. It is characteristic that most piscivores (4 species), most omnivores (4 species) and a few zoobenthos feeders (2 species) were ubiquitous. Most species kept a distance from piscivores. Each set of two species of Aufwuchs eater and two species of omnivore often frequented together suggesting a cooperative feeding.
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... This utilization of similar food resources by multiple species suggests that niche (diet) partitioning and coexistence mechanisms will underlie the cichlid community. In Lake Tanganyika, Hori et al. (1983) conducted a field survey at the Luhanga shore in the northwestern part of Lake Tanganyika. In 1980, they carried out a census to count every species of rock-dwelling cichlid fish with SCUBA diving in a 20 m Â 20 m quadrat set on predominantly rock and stone bottom, from the shore line to the depth of about 11 m. ...
... compressiceps, G. pfefferi, L. callipterus, N. leleupi, N. toae, and small size N. fasciatus) specialized on shrimp (more than 80% of whole stomach contents). For Fig. 11 Herbivorous cichlids genus Petrochromis inhabiting at shallow rocky shore (from Yamaoka 1983). Petrochromis trewavasae (male, (a)), P. orthognatus (female (b)), P. polyodont (male (c)), P. famula (female (d)), and P. fasciolatus (male (e)) small L. lemairii (27-66 mm in standard length), shrimp are important prey (more than 50% of whole stomach contents), but they also feed on small fishes. ...
... On the other hand, young smaller males sometimes join a foraging group of two to seven conspecifics and cruise along the substrate and take small invertebrates in a huge area (Yuma 1994). This species also forms a foraging school with individuals of G. pfefferi (Hori et al. 1983). Solitary individuals or a pair of N. furcifer defend a small area on the overhanging rock surface and forage on benthic animals from on or near the rock surface. ...
Chapter
Among the ancient Great Lakes of East Africa, Lake Tanganyika is the oldest and possesses about 250 species of cichlid fishes. Most are endemic species and have rapidly evolved with high diversification in morphology, behavior, and ecology through adaptive radiation into novel habitats. Cichlids are distributed from the shallow margins to the deep area in the lake, while the assemblages of the cichlid community indicate higher density and diversity in the shallow rocky regions in which some cichlid species that utilize similar diet niches coexist. In this chapter, I summarize research about feeding ecology, morphological traits in relation to foraging behavior and diet utilization, and food web structure in the cichlid community of Lake Tanganyika. Furthermore, I point out future directions in terms of current novel approaches that would contribute to understanding sympatric speciation with expanding novel diet/feeding niches, the diversification of species, food web constructions, and mechanisms for coexistance; including evo-devo, symbiosis with microorganisms in guts, stable isotope analysis, and behavioral syndrome/personality studies for the Lake Tanganyika cichlids. The integration of these studies will help us understand the ecological and evolutionary insights of feeding ecology and provide new aspects of adaptive radiation and sympatric speciation in Lake Tanganyika cichlids.
... Adult P. microlepis approach prey fish from behind to snatch scales directly from their flanks, and mainly target algae-eating cichlids (Hori et al., 1983;Nshombo et al., 1985;Hori, 1993;Takeuchi et al., 2016). This species shows a left-right mouth polymorphism, potentially as a frequency-dependent hunting strategy (Hori et al., 1983;Hori, 1993;Takeuchi et al., 2016;Raffini & Meyer, 2019). ...
... Adult P. microlepis approach prey fish from behind to snatch scales directly from their flanks, and mainly target algae-eating cichlids (Hori et al., 1983;Nshombo et al., 1985;Hori, 1993;Takeuchi et al., 2016). This species shows a left-right mouth polymorphism, potentially as a frequency-dependent hunting strategy (Hori et al., 1983;Hori, 1993;Takeuchi et al., 2016;Raffini & Meyer, 2019). In their hunting behaviour, adult P. microlepis rotate their body, with both jaws pressed against the body of the prey (Takahashi et al., 2007a;Takeuchi et al., 2012). ...
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Although parental care is known to occur in a wide range of teleost fishes, postnatal provisioning of nutrition has been documented rarely. Here, we describe a novel example of bi-parental care in a teleost, i.e. mucus-provisioning behaviour in the scale-eating cichlid Perissodus microlepis endemic to Lake Tanganyika. Field observations revealed that young guarded by their parents frequently glanced towards the body surface of both parents. Furthermore, analyses of stomach contents of the young found the presence of ingested mucus, confirming that the young feed on the mucus secretions of their parents. The frequency of glancing behaviour increased with size of the young up to ~13 mm in standard length, but then declined with further growth. Additionally, the frequency of glancing of young towards their parents was higher when the frequency of foraging on plankton was lower. Underwater cage experiments revealed a higher rate of growth in the young kept in direct contact with their parents than in those not allowed direct contact. We conclude that glancing behaviour in young P. microlepis is a form of direct parental nourishment that confers growth benefits to the young when food abundance is low.
... We chose these species to be representative of the range of social behaviours and morphologies found across Lamprologine cichlids to ensure, as far as possible, that the developed protocol could be used in other species in the future. All of the species included maintain similar territories and have similar diets; however, N. pulcher feed primarily on midwater zooplankton, whereas T. temporalis typically scrape algae from rocks (aufwuchs), N. tretocephalus and L. meleagris feed on zoobenthos, N. mulifasciatus feed on zoobenthos and midwater zooplankton, and J. dickfeldi are omnivorous (Hori, Yamaoka, & Kenzi, 1983;Konings, 1998). ...
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It has been hypothesised that some specialised cognitive abilities may have evolved because of the challenges of living in complex social environments. Therefore, more-social species might be able to learn faster than less-social species. The aim of this study was to develop a learning framework to test how more-and less-social Lamprologine cichlid fishes perform across associative learning tasks. These cichlids are a group of closely related species with similar ecologies and life histories but varying degrees of sociality, making them an ideal group for comparative learning studies. We found that three nongrouping cichlids (Telmatochromis temporalis, Lamprologus meleagris, and Neolamprologus treto-cephalus) outperformed three closely related highly social, cooperatively breeding cichlids (N. pulcher, N. multifasciatus, and Julidochromis dickfeldi) on an associative learning task based on food rewards. However, we hypothesised that these differences may be caused by the social environment during testing and might not reflect true cognitive differences. Indeed, when we drilled down and compared just two species across four different social conditions, we found that the social environment during learning trials affected the performance of the highly social N. pulcher and the less-social T. temporalis differently. We then performed further experiments with both N. pulcher and T. temporalis under more natural social settings. Under these more natural social conditions, we found that N. pulcher learned to differentiate accessible and inaccessible shelters faster than T. temporalis. These findings highlight the potential for expanding comparative experiments investigating the relationship between sociality and cognition and emphasise the crucial role social environment plays in learning outcomes.
... Several ecological factors may explain the stability of the relative abundance and species richness, including habitat diversity and the resultant fish diversity of the Malebo Pool the diversity of feeding habits and the way in which communities were associated. These factors were also identified as contributing towards the stability of the community of Distichodus genus (Mbadu 2011), of the whole fish community in the Malebo Pool ) and of Cichlid communities in lake Tanganika (Hori et al. 1983;Yamaoka et al. 1986;Kawanabe et al. 1997). ...
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At the level of Malebo Pool of the River Congo, ecological studies of Mochokidae fish communities are non-existent. This study was carried out monthly from July 2009 to October 2010, and bimonthly from March 2011 to August 2013 through experimental fishing in seven lotic and lentic stations to specify the spatio-temporal structure of these relatively abundant fish. Multivariate analysis (Canonical Redundancy Analysis) of Mochokidae stands and their habitats show segregation of species between lotic and lentic areas. The lotic habitats (Nganda Mabanga and Ile Mimosa) are colonised by species such as Chiloglanis congicus, Euchilichthys guentheri, Synodontis brichardi, Synodontis longirostris and Synodontis ornatipinnis that are located in rocky substrates with high current speed. Lentic habitats (Ngamanzo-Japon-Mipongo-Molondo-Kingabwa complex) are colonised by other species such as Synodontis acanthomias, S. decorus, S. alberti, S. notatus, S. congicus, S. caudalis, S. soloni, S. pleurops, S. nummifer and S. contractus that live in muddy and sandy substrates with submerged vegetation and weak current. The study aims to contribute towards better management and conservation of the aquatic ecosystem, specifically the habitat of the Mochokidae species, in light of the negative impacts of human developments in the Democratic Republic of the Congo.
... We used individuals of the sympatric, piscivorous cichlid Lepidiolamprologus elongatus as a stimulus to elicit territory defence behaviours in one of the behavioural tests (see below). In Lake Tanganyika, this species is the main predator of N. pulcher (Heg, Bachar, Brouwer, & Taborsky, 2004;Hori, Yamaoka, & Takamura, 1983). ...
Article
Social animals interact frequently with conspecifics, and their behaviour is influenced by social context, environmental cues and the behaviours of interaction partners, allowing for adaptive, flexible adjustments to social encounters. This flexibility can be limited by part of the behavioural variation being genetically determined. Furthermore, behaviours can be genetically correlated, potentially constraining independent evolution. Understanding social behaviour thus requires carefully disentangling genetic, environmental, maternal and social sources of variations as well as the correlation structure between behaviours. Here, we assessed heritability, maternal, common environment and social effects of eight social behaviours in Neolamprologus pulcher, a cooperatively breeding cichlid. We bred wild-caught fish in a paternal half-sibling design and scored ability to defend a resource against conspecifics, to integrate into a group and the propensity to help defending the group territory ("helping behaviour"). We assessed genetic, social and phenotypic correlations within clusters of behaviours predicted to be functionally related, namely "competition," "aggression," "aggression-sociability," "integration" and "integration-help." Helping behaviour and two affiliative behaviours were heritable, whereas there was little evidence for a genetic basis in all other traits. Phenotypic social effects explained part of the variation in a sociable and a submissive behaviour, but there were no maternal or common environment effects. Genetic and phenotypic correlation within clusters was mostly positive. A group's social environment influenced covariances of social behaviours. Genetic correlations were similar in magnitude but usually exceeding the phenotypic ones, indicating that conclusions about the evolution of social behaviours in this species could be provisionally drawn from phenotypic data in cases where data for genetic analyses are unobtainable.
... We conducted a long-term survey on the ratios of laterality in the populations of the two species of scale-eater on a rocky shore at Kasenga Point in the southern end of Lake Tanganyika (near Mpulungu, Northern District, Republic of Zambia). It has been shown that the fish community in the littoral rocky shore of this lake is mainly composed of cichlid fishes and is very stable with the densities of most species being unchanged over many years [17,28,39]. Then, in order to know the effect of laterality of one species on another, it may be enough to know the ratios of laterality of the two species of scale-eater. ...
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Scale-eating cichlid fishes, Perissodus spp., in Lake Tanganyika have laterally asymmetrical bodies, and each population is composed of righty and lefty morphs. Righty morphs attack the right side of prey and lefty morphs do the opposite. This anti-symmetric dimorphism has a genetic basis. Temporal changes in the frequencies of morphs in two cohabiting scale-eating species (Perissodus microlepis and P. straeleni) were investigated over a 31-year period on a rocky shore at the southern end of the lake. Dimorphism was maintained dynamically during the period in both species, and the frequencies oscillated with a period of about four years in a semi-synchronized manner. Recent studies have indicated that this type of anti-symmetric dimorphism is shared widely among fishes, and is maintained by frequency-dependent selection between predator and prey species. The combinations of laterality in each scale-eater and its victim were surveyed. The results showed that “cross-predation”, in which righty predators catch lefty prey and lefty predators catch righty prey, occurred more frequently than the reverse combination (“parallel-predation”). The cause of the predominance of cross-predation is discussed from the viewpoint of the physical and sensory abilities of fishes.
Chapter
This chapter summarizes 200 years of the study of cichlid fishes, ranging from the first descriptions of South American and African species in early natural histories to the work of twentieth-century biologists. The rise and influence of evolutionary theory and the development of new knowledge and techniques in the study of genetics are considered central influences in a variety of fields of research involving cichlids, including ecology, ethology, aquaculture, and fisheries. Significant developments and their historical context are considered in relation to the current state of a variety of cichlid research programs, showcasing the extent to which cichlids have become both model species in evolutionary biology and a crucial species in global food production.
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The African Great Lakes are characterized by an extraordinary diversity of endemic cichlid fish species. The cause of this diversity is still largely unknown. Most studies have tried to solve this question by focusing on macro-evolutionary processes, such as speciation. However, the ecological processes determining local cichlid diversity have so far been understudied, even though knowledge on these might be crucial for understanding larger scale biodiversity patterns. Using trait, environmental and abundance data of cichlid fishes along 36 transects, we have studied how differences in local environmental conditions influence cichlid community assembly in the littoral of Lake Tanganyika, Zambia. We investigated changes in average trait values and in trait-based community assembly processes along three key environmental gradients. Species diversity and local abundance decreased with increasing sand cover and diet-associated traits changed with depth. Analyses on within-community trait diversity patterns indicated that cichlid community assembly was mainly driven by stochastic processes, to a smaller extent by processes that limit the similarity among co-existing species and least by filtering processes that limit the range of species traits occurring in an environment. Despite, the low impact of habitat filtering processes, we find community dissimilarity to increase with increasing environmental difference. Our results suggest that local environmental conditions determine cichlid abundance, while the predominance of stochastic community assembly across all environments explains why the communities with the highest abundances contain most species.
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Electromyography, motion analysis, osteology, myology and feeding behaviour of a morphologically specialized monophyletic lineage of cichlids in Lake Tanganyika have revealed that Eretmodus, Spathodus and Tanganicodus possess a feeding apparatus with a more extensive functional repertoire than that of any other teleost studied to date. When collecting a wide range of foods by inertial suction this trophic group can employ two strategies, a preprogrammed cyclical, energy saving pattern, or a modulated mode effected by extensive overlap of the firing patterns of multiple muscles resulting in a precise control of the magnitude and direction of suction. When dislodging sessile prey from the substrate the complexity of electromyographic and kinematic patterns increases. Because upper jaw protrusion can be effected and controlled independently from the complex couplings causing mouth opening and movements of the suspensory apparatus, a new decoupled model of upper jaw protrusion is proposed. The decoupled model predicts that upper jaw protrusion can be effected directly by contraction of epaxial muscles that raise the neurocranium, causing the premaxillae to slide anteroventrally. Upper jaw protrusion can be modulated continuously and directly by balanced cocontractions of antagonistic muscle sets giving the decoupled model an improved function over a very extensive range. The morphologically symmetrical muscular apparatus can function asymmetrically. Very pronounced asymmetrical firings of multiple muscles produce a continuously modulated jaw mechanism with an extensive repertoire.
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The measurement of spatial association between two species is considered on the basis of interspecies mean crowding. Two indices of overlapping, γ andC μ, are derived as geometric and weighted arithmetic means of the same component ratios related to inter- and intraspecies mean crowdings. Both indices behave in a similar way, ranging from 1 when the distributions of two species are completely overlapped to 0 when they are completely exclusive with each other. The former is essentially identical with indices proposed byKuno (1968) andPianka (1973), and the latter is a modified form ofMorisita’s (1959)C δ index. Indices to measure the degree of spatial correlation between species, ω andR μ, are then derived for both kinds of overlapping indices, which vary from 1 in complete overlapping, through 0 in independent occurrence, to −1 in complete exclusion. Various kinds of interspecies association are analyzed using these indices and an extended form of the$$\mathop m\limits^ * - m$$ regression graph which provides a convenient way of indicating the spatial interrelation between two species as well as distribution patterns of respective species. The method presented in this paper may also be applicable to compare temporal distribution patterns between species, similarity between communities, etc. For such a wider application which includes continuous as well as discrete distributions, the interpretation of intra- and interspecies mean crowdings is not necessarily appropriate, and hence the concept of mean concentration with the symbols$$\mathop m\limits^ * - m$$ and$$\mathop c\limits^ * _X \left( { = \mathop m\limits^ * _X + 1} \right)$$ for intraspecies relation and$$\mathop c\limits^ * _Y \left( { = \mathop m\limits^ * Y + 1} \right)$$ and$$\mathop c\limits^ * _{XY} \left( { = \mathop m\limits^ * _{XY} } \right)$$ for interspecies relation is suggested.
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The fish fauna near Uvira is composed of 13 families and more than 110 species--38 of non-cichlids and 72 of cichlids. It is considerably different from that in the Ruzizi estuaries and on the Luhanga rocky shores. Stream or estuary species such as Protopterus, Sarogherodon niloticus and cyprinids are abundant in the former, while Synodontis, Mastacembelus and cichlid fishes are in the latter. Some stream or estuary fishes such as Citharinus, Hydrocynus and Tetraodon, which are common in the Maragarasi estuaries, do not seem to inhabit near the Ruzizis. The proportion of endemic species is much higher on the rocky shores than at the muddy area and especially that of cichlids reaches 100%. Sixty-one species of cichilds inhabit the rocky shore of Luhanga in high density and most of them are rock dwellers except Boulengerochromis and Hemibates etc. The proportion of the rock dwellers at Luhanga to the whole rock dwellers of the lake is also high, reaching 70% in cichlids.
Histoire du peuplement et origine des espeees de la faune ichthyologique du lac Tan-ganika
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Poll, M.. 1950. Histoire du peuplement et origine des espeees de la faune ichthyologique du lac Tan-ganika. Annis Soc. r. Zool. Belg., 81: 111-140
Les communautes Ccologique des poissons Cichlidae au lac Tanganika
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