A euryhaline fish, lost in the desert: The unexpected metapopulation structure of Coptodon guineensis (Günther, 1862) in the Sebkha of Imlili

Abstract

Euryhaline Cichlid fish of the species Coptodon guineensis are present in different water holes situated in a dried depression in the desert in the extreme South of Morocco, the Sebkha of Imlili. A genetic survey of this population, using complete sequences of the ND2 gene (mtDNA) and sixteen microsatellite loci, revealed that the fish in the sebkha did not form a single population, but rather a metapopulation. This metapopulational structure may be regarded as good news from the point of view of the conservation of fish in the sebkha. Although small individual populations may have short, finite life spans, the metapopulation as a whole is more stable, because immigrants from one population are likely to re-colonize the habitat, left open by the extinction of another.

Fish out of water: Genomic insights into persistence of rainbowfish populations in the desert

“…Many desert species opportunistically breed and disperse when there are favorable conditions and hydrological connectivity, such as during rare flooding events. These high dispersal species act as cyclical boom-bust metapopulations, with local extinction during dry periods and recolonization in wet periods (Huey et al 2011;Agnèse et al 2018). Their level of population connectivity is limited by riverine connectivity, with low or nil population structure within river catchments, moderate structure among catchments in the same basin (i.e., catchments that flow to a common outlet), and relatively high structure among river basins (Murphy et al 2015).…”

Parasites of Moroccan desert Coptodon guineensis (Pisces, Cichlidae): transition and resilience in a simplified hypersaline ecosystem

“…Hence, its presence in hypersaline waters at Sebkha Imlili would have to be explained by it having switched to C. guineensis as definitive host from a freshwater tilapia (e.g., native C. zillii when the Sebkha was a lagoon fed by freshwater during the Holocene (Green Sahara period) [37]. In support of such a freshwater origin are that i) C. guineensis is known to occur in some freshwater rivers [2]; ii) the freshwater tilapia O. aureus and C. zillii (often reported as host for A. (A.)…”

“…tilapiae. We should also consider that the acanthocephalan species could be an altogether different and cryptic species because it has been isolated for a long period of time, and given that the Coptodon from the Sebkha Imlili is possibly an "incipient" species of tilapia [2]. Given what we know at this stage however, it is most reasonable to identify this acanthocephalan as A.…”

“…The area exhibits a great richness in terms of biodiversity, with recent studies providing new data on its reptiles [69], mammals [83], birds [81,86], and flora [51]. On the other hand, the diversity of the aquatic fauna is relatively simple, with three species of crustaceans, three species of gastropod mollusks [40], and a single cichlid fish, Coptodon guineensis (Günther, 1862) [2,48,84]. Because these organisms are believed to have been trapped in the water pools when these were formed during the Holocene after the Green Sahara period, these aquatic animals are considered to be relics of the past [37].…”

Contribution of the Catchment Area to the Hydrology of a Saharan Wetland, the Imlili Sebkha (Dakhla Region, Morocco) – Use of GIS and Satellite Data

“…This genesis earned it the character of a natural dam guelta, more particularly a permanent dune guelta, of which the Imlili wetland is the only known representative (Dakki et al 2020). The presence in this wetland of a cichlid fish, the Guinea tilapia Coptodon guineensis, a sign of water permanence, has drawn the attention of many researchers to this environment (Qninba et al 2009; Agnèse et al 2018;Himmi et al 2020).…”