Article

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

Hydrobiologia (Impact Factor: 2.21). 12/2008; 615(1):57-68. DOI: 10.1007/978-1-4020-9582-5_5

ABSTRACT 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.

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    • "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). "
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    • "Obviously, the most relevant assessment of the variance in reproductive success would be obtained from parentage reconstructions in natural populations (e.g., Weatherhead & Boag, 1997; Coltman et al., 1999; Friedl & Klump, 1999; Serbezov et al., 2010), with the caveat that this approach depends on the comprehensive sampling of juveniles and potential parents. The large census size of Tropheus (Sturmbauer et al., 2008) impedes the identification of closely related individuals in a randomly drawn sample; for example, the probability of an individual's parent being included in population samples of 200–300 Tropheus was estimated to be only 1–7%, and only 4–10 individuals were assigned a parent in these samples (Koch et al., 2008). The presented experiment complements a simulation of Tropheus reproduction, which suggested that pair bonding and monogamous spawning do not necessarily curb the potential for sexual selection, if concordant female preferences provide for variance in male reproductive success (Sefc, 2008). "
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