Abundance, distribution, and territory areas of rock-dwelling Lake Tanganyika cichlid fish species

Hydrobiologia (Impact Factor: 2.28). 12/2008; 615(1):57-68. DOI: 10.1007/978-1-4020-9582-5_5


Lake Tanganyika, the second-oldest and second-deepest lake in the world, harbors an impres-sive cichlid fish fauna counting about 250 endemic species that are characterized by a great level of ecological, morphological, and behavioral specializa-tion. This study describes and compares cichlid fish communities at two rocky shores with differential human impact in the south of Lake Tanganyika. Species inventories and depth-dependent abundances were elaborated. About 41 and 46 sympatric cichlid species were recorded in the two study sites, respec-tively. Variabilichromis moorii was the most abundant species (29–60% of total number of fishes), followed by Aulonocranus dewindti (3–19%), Tro-pheus moorii (12%), Ophthalmotilapia ventralis (4–10%), Eretmodus cyanostictus (6–11%), and Cyathopharynx furcifer (0.01–9%). All other species had abundances below 5%. It further emerged that large cichlids such as Petrochromis species, Cyatho-pharynx furcifer, and Lobochilotes labiatus were very rare at one location, with frequencies of 0.55% or less. Territorial sizes of three particularly abundant species, Variabilichromis moorii, Aulonocranus dew-indti, and Tropheus moorii, were assessed by behavioral observations. We distinguished between territorial core areas and total defended area, yielding average core areas between 0.4 (V. moorii) and 1.6 m 2 (T. moorii), and total defended areas averag-ing for each species between 1.6 (V. moorii) and 5.0 m 2 (A. dewindti) with no significant differences between the two study sites. The data on individual densities are also relevant for evolutionary studies, in that they allow more accurate calculations of effec-tive population sizes.

Download full-text


Available from: Stephan Koblmüller,
  • Source
    • "After spawning, females abandon their mate for maternal mouthbrooding (Yanagisawa and Nishida 1991). Territory quality influences male mating success (Yanagisawa and Nishida 1991; Hermann et al. 2015), and competition for territories ensues from the high density of Tropheus in the rocky littoral of Lake Tanganyika (e.g., Sturmbauer et al. 2008). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Assortative mating promotes reproductive isolation and allows allopatric specia-tion processes to continue in secondary contact. As mating patterns are determined by mate preferences and intrasexual competition, we investigated male–male competition and behavioral isolation in simulated secondary contact among allopatric populations. Three allopatric color morphs of the cichlid fish Tropheus were tested against each other. Dyadic male–male contests revealed dominance of red males over bluish and yellow-blotch males. Reproductive isolation in the presence of male–male competition was assessed from genetic parent-age in experimental ponds and was highly asymmetric among pairs of color morphs. Red females mated only with red males, whereas the other females performed variable degrees of heteromorphic mating. Discrepancies between mating patterns in ponds and female preferences in a competition-free, two-way choice paradigm suggested that the dominance of red males interfered with positive assortative mating of females of the subordinate morphs and provoked asymmet-ric hybridization. Between the nonred morphs, a significant excess of negative assortative mating by yellow-blotch females with bluish males did not coincide with asymmetric dominance among males. Hence, both negative assortative mating preferences and interference of male–male competition with positive assorta-tive preferences forestall premating isolation, the latter especially in environments unsupportive of competition-driven spatial segregation.
    Ecology and Evolution 04/2015; DOI:10.1002/ece3.1372 · 2.32 Impact Factor
  • Source
    • "Males and females actively defend separate feeding territories in the shallow littoral of Lake Tanganyika, East Africa, and browse on epilithic algae. The densely packed, contiguous territories range in size from 0.25 to 4 m 2 (Takamura 1984; Sturmbauer et al. 2008), and observations of frequent replacements and territory expansions upon removal of territory holders (Yanagisawa and Nishida 1991) suggest strong intraspecific competition (Grant 1997). Tropheus are maternal mouthbrooders. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Non-sexual social selection can underlie the evolution of sexually monomorphic phenotypes. A causal relationship between territorial competition and sexual monomorphism predicts that male and female competitors should employ similar contest behavior and that contest outcome should depend on the same traits in males and females. We test this prediction in a sexually monomorphic cichlid fish of the genus Tropheus, in which males and females defend individual feeding territories. Lineages basal to Tropheus are sexually dimorphic and have non-territorial females, suggesting that a switch to female territoriality and loss of sexual dimorphism occurred in the Tropheus lineage. We compare rates of agonistic behavior and the effects of body size asymmetries on competitive success between male-male and female-female contests in an experimental setup. Body size asymmetry had the same effect in male and female contests, being negatively correlated with contest duration and positively correlated with the probability of winning. Male and female winners employed the same rates of frontal and lateral displays as well as charges against their opponents. Contest duration was longer in females. In tied contests, females displayed more than males. Our data suggest that intraspecific contest competition for territories selects for large body size in both sexes and support a link between the evolution of female territoriality and the loss of sexual size dimorphism in Tropheus. Electronic supplementary material The online version of this article (doi:10.1007/s00265-014-1870-0) contains supplementary material, which is available to authorized users.
    Behavioral Ecology and Sociobiology 04/2015; 69(4). DOI:10.1007/s00265-014-1870-0 · 2.35 Impact Factor
  • Source
    • "Tropheus lives at rock and cobble shores where it inhabits a wide range of water depths, sometimes down to 40 m, but its highest density is between the depths of 0.5 and 5 m (Kohda and Yanagisawa, 1992; Sturmbauer et al., 2008). The genus is highly specialized and occupies the trophic niche of mainly browsing on filamentous algae, whereas other genera utilize different resources in this complex littoral species community (Sturmbauer et al., 1992; Konings, 1998). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Allopatric speciation often yields ecologically equivalent sister species, so that their secondary admixis enforces competition. The shores of Lake Tanganyika harbor about 120 distinct populations of the cichlid genus Tropheus, but only some are sympatric. When alone, Tropheus occupies a relatively broad depth zone, but in sympatry, fish segregate by depth. To assess the effects of competition, we studied the partial co-occurrence of Tropheus moorii 'Kaiser' and 'Kirschfleck' with Tropheus polli. A previous study demonstrated via standardized breeding experiments that some observed differences between Tropheus 'Kaiser' living alone and in sympatry with T. polli have a genetic basis despite large-scale phenotypic plasticity. Using geometric morphometrics and neutral genetic markers, we now investigated whether sympatric populations differ consistently in body shape from populations living alone and if the differences are adaptive. We found significant differences in mean shape between non-sympatric and sympatric populations, whereas all sympatric populations of both color morphs clustered together in shape space. Sympatric populations had a relatively smaller head, smaller eyes and a more anterior insertion of the pectoral fin than non-sympatric populations. Genetically, however, non-sympatric and sympatric 'Kaiser' populations clustered together to the exclusion of 'Kirschfleck'. Genetic distances, but not morphological distances, were correlated with geographic distances. Within- and between-population covariance matrices for T. moorii populations deviated from proportionality. It is thus likely that natural selection acts on both phenotypic plasticity and heritable traits and that both factors contribute to the observed shape differences. The consistency of the pattern in five populations suggests ecological character displacement.Heredity advance online publication, 25 September 2013; doi:10.1038/hdy.2013.78.
    Heredity 09/2013; 112(2). DOI:10.1038/hdy.2013.78 · 3.81 Impact Factor
Show more