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Carruthers M, Edgley DE, Saxon AD, Gabagambi NP, Shechonge A, Miska EA, Durbin R, Bridle JR, Turner GF, Genner MJ. Ecological Speciation Promoted by Divergent Regulation of Functional Genes Within African Cichlid Fishes. Mol Biol Evol 2022; 39:msac251. [PMID: 36376993 PMCID: PMC10101686 DOI: 10.1093/molbev/msac251] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Rapid ecological speciation along depth gradients has taken place repeatedly in freshwater fishes, yet molecular mechanisms facilitating such diversification are typically unclear. In Lake Masoko, an African crater lake, the cichlid Astatotilapia calliptera has diverged into shallow-littoral and deep-benthic ecomorphs with strikingly different jaw structures within the last 1,000 years. Using genome-wide transcriptome data, we explore two major regulatory transcriptional mechanisms, expression and splicing-QTL variants, and examine their contributions to differential gene expression underpinning functional phenotypes. We identified 7,550 genes with significant differential expression between ecomorphs, of which 5.4% were regulated by cis-regulatory expression QTLs, and 9.2% were regulated by cis-regulatory splicing QTLs. We also found strong signals of divergent selection on differentially expressed genes associated with craniofacial development. These results suggest that large-scale transcriptome modification plays an important role during early-stage speciation. We conclude that regulatory variants are important targets of selection driving ecologically relevant divergence in gene expression during adaptive diversification.
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Affiliation(s)
- Madeleine Carruthers
- School of Biological Sciences, University of Bristol,
Bristol BS8 1TQ, United
Kingdom
| | - Duncan E Edgley
- School of Biological Sciences, University of Bristol,
Bristol BS8 1TQ, United
Kingdom
| | - Andrew D Saxon
- School of Biological Sciences, University of Bristol,
Bristol BS8 1TQ, United
Kingdom
| | - Nestory P Gabagambi
- Tanzanian Fisheries Research Institute, Kyela Research
Centre, P.O. Box 98, Kyela, Mbeya, Tanzania
| | - Asilatu Shechonge
- Tanzanian Fisheries Research Institute, Dar es Salaam Research
Centre, P.O. Box 9750, Dar es Salaam, Tanzania
| | - Eric A Miska
- Wellcome/CRUK Gurdon Institute, University of Cambridge,
Cambridge CB2 1QN, United
Kingdom
- Department of Genetics, University of Cambridge,
Cambridge CB2 3EH, United
Kingdom
- Wellcome Sanger Institute, Wellcome Genome Campus,
Cambridge CB10 1SA, United Kingdom
| | - Richard Durbin
- Department of Genetics, University of Cambridge,
Cambridge CB2 3EH, United
Kingdom
- Wellcome Sanger Institute, Wellcome Genome Campus,
Cambridge CB10 1SA, United Kingdom
| | - Jon R Bridle
- School of Biological Sciences, University of Bristol,
Bristol BS8 1TQ, United
Kingdom
| | - George F Turner
- School of Natural Sciences, Bangor University,
Bangor, Wales LL57 2UW, United
Kingdom
| | - Martin J Genner
- School of Biological Sciences, University of Bristol,
Bristol BS8 1TQ, United
Kingdom
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2
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Ciezarek A, Ford AG, Etherington GJ, Kasozi N, Malinsky M, Mehta TK, Penso-Dolfin L, Ngatunga BP, Shechonge A, Tamatamah R, Haerty W, Di Palma F, Genner MJ, Turner GF. Whole genome resequencing data enables a targeted SNP panel for conservation and aquaculture of Oreochromis cichlid fishes. Aquaculture 2022; 548:737637. [PMID: 35177872 PMCID: PMC8655616 DOI: 10.1016/j.aquaculture.2021.737637] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 10/21/2021] [Accepted: 10/22/2021] [Indexed: 06/14/2023]
Abstract
Cichlid fish of the genus Oreochromis form the basis of the global tilapia aquaculture and fisheries industries. Broodstocks for aquaculture are often collected from wild populations, which in Africa may be from locations containing multiple Oreochromis species. However, many species are difficult to distinguish morphologically, hampering efforts to maintain good quality farmed strains. Additionally, non-native farmed tilapia populations are known to be widely distributed across Africa and to hybridize with native Oreochromis species, which themselves are important for capture fisheries. The morphological identification of these hybrids is particularly unreliable. Here, we describe the development of a single nucleotide polymorphism (SNP) genotyping panel from whole-genome resequencing data that enables targeted species identification in Tanzania. We demonstrate that an optimized panel of 96 genome-wide SNPs based on FST outliers performs comparably to whole genome resequencing in distinguishing species and identifying hybrids. We also show this panel outperforms microsatellite-based and phenotype-based classification methods. Case studies indicate several locations where introduced aquaculture species have become established in the wild, threatening native Oreochromis species. The novel SNP markers identified here represent an important resource for assessing broodstock purity in hatcheries and helping to conserve unique endemic biodiversity.
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Affiliation(s)
- A. Ciezarek
- Earlham Institute, Norwich Research Park, Norwich NR4 7UZ, UK
| | - Antonia G.P. Ford
- Department of Life Sciences, Roehampton University, London SW15 4JD, UK
| | | | - Nasser Kasozi
- National Agricultural Research Organisation, Abi Zonal Agricultural Research and Development Institute, P.O. Box 219, Arua, Uganda
| | - Milan Malinsky
- Zoological Institute, Department of Environmental Sciences, University of Basel, 4051 Basel, Switzerland
| | - Tarang K. Mehta
- Earlham Institute, Norwich Research Park, Norwich NR4 7UZ, UK
| | - Luca Penso-Dolfin
- Silence Therapeutics GmbH, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Benjamin P. Ngatunga
- Tanzania Fisheries Research Institute (TAFIRI), PO. Box 9750, Dar es Salaam. Tanzania
| | - Asilatu Shechonge
- Tanzania Fisheries Research Institute (TAFIRI), PO. Box 9750, Dar es Salaam. Tanzania
| | - Rashid Tamatamah
- Tanzania Fisheries Research Institute (TAFIRI), PO. Box 9750, Dar es Salaam. Tanzania
| | - Wilfried Haerty
- Earlham Institute, Norwich Research Park, Norwich NR4 7UZ, UK
| | - Federica Di Palma
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TU, UK
| | - Martin J. Genner
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
| | - George F. Turner
- School of Natural Sciences, Bangor University, Bangor LL57 2UW, UK
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3
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Blackwell T, Ford AGP, Ciezarek AG, Bradbeer SJ, Gracida Juarez CA, Smith AM, Ngatunga BP, Shechonge A, Tamatamah R, Etherington G, Haerty W, Di Palma F, Turner GF, Genner MJ. Newly discovered cichlid fish biodiversity threatened by hybridization with non-native species. Mol Ecol 2020; 30:895-911. [PMID: 33063411 DOI: 10.1111/mec.15638] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 08/24/2020] [Indexed: 12/24/2022]
Abstract
Invasive freshwater fishes are known to readily hybridize with indigenous congeneric species, driving loss of unique and irreplaceable genetic resources. Here we reveal that newly discovered (2013-2016) evolutionarily significant populations of Korogwe tilapia (Oreochromis korogwe) from southern Tanzania are threatened by hybridization with the larger invasive Nile tilapia (Oreochromis niloticus). We use a combination of morphology, microsatellite allele frequencies and whole genome sequences to show that O. korogwe from southern lakes (Nambawala, Rutamba and Mitupa) are distinct from geographically disjunct populations in northern Tanzania (Zigi River and Mlingano Dam). We also provide genetic evidence of O. korogwe × niloticus hybrids in three southern lakes and demonstrate heterogeneity in the extent of admixture across the genome. Finally, using the least admixed genomic regions we estimate that the northern and southern O. korogwe populations most plausibly diverged ~140,000 years ago, suggesting that the geographical separation of the northern and southern groups is not a result of a recent translocation, and instead these populations represent independent evolutionarily significant units. We conclude that these newly discovered and phenotypically unique cichlid populations are already threatened by hybridization with an invasive species, and propose that these irreplaceable genetic resources would benefit from conservation interventions.
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Affiliation(s)
| | - Antonia G P Ford
- Department of Life Sciences, Whitelands College, University of Roehampton, London, UK
| | - Adam G Ciezarek
- Earlham Institute, Norwich Research Park Innovation Centre, Norwich, UK
| | | | | | - Alan M Smith
- Department of Biological Sciences, University of Hull, Hull, UK
| | | | - Asilatu Shechonge
- Tanzania Fisheries Research Institute (TAFIRI), Dar es Salaam, Tanzania
| | - Rashid Tamatamah
- Tanzania Fisheries Research Institute (TAFIRI), Dar es Salaam, Tanzania
| | | | - Wilfried Haerty
- Earlham Institute, Norwich Research Park Innovation Centre, Norwich, UK
| | - Federica Di Palma
- Earlham Institute, Norwich Research Park Innovation Centre, Norwich, UK.,Department of Biological and Medical Sciences, University of East Anglia, Norwich, UK
| | - George F Turner
- School of Biological Sciences, Bangor University, Bangor, UK
| | - Martin J Genner
- School of Biological Sciences, University of Bristol, Bristol, UK
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4
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White LJ, Sutton G, Shechonge A, Day JJ, Dasmahapatra KK, Pownall ME. Adaptation of the carbamoyl-phosphate synthetase enzyme in an extremophile fish. R Soc Open Sci 2020; 7:201200. [PMID: 33204476 PMCID: PMC7657897 DOI: 10.1098/rsos.201200] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 09/21/2020] [Indexed: 05/03/2023]
Abstract
Tetrapods and fish have adapted distinct carbamoyl-phosphate synthase (CPS) enzymes to initiate the ornithine urea cycle during the detoxification of nitrogenous wastes. We report evidence that in the ureotelic subgenus of extremophile fish Oreochromis Alcolapia, CPS III has undergone convergent evolution and adapted its substrate affinity to ammonia, which is typical of terrestrial vertebrate CPS I. Unusually, unlike in other vertebrates, the expression of CPS III in Alcolapia is localized to the skeletal muscle and is activated in the myogenic lineage during early embryonic development with expression remaining in mature fish. We propose that adaptation in Alcolapia included both convergent evolution of CPS function to that of terrestrial vertebrates, as well as changes in development mechanisms redirecting CPS III gene expression to the skeletal muscle.
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Affiliation(s)
- Lewis J. White
- Biology Department, University of York, York YO10 5DD, UK
- Author for correspondence: Lewis J. White e-mail:
| | - Gemma Sutton
- Biology Department, University of York, York YO10 5DD, UK
| | - Asilatu Shechonge
- Tanzania Fisheries Research Institute, PO BOX 98, Kyela, Mbeya, Tanzania
| | - Julia J. Day
- Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
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5
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Alzaylaee H, Collins RA, Rinaldi G, Shechonge A, Ngatunga B, Morgan ER, Genner MJ. Correction: Schistosoma species detection by environmental DNA assays in African freshwaters. PLoS Negl Trop Dis 2020; 14:e0008721. [PMID: 32870920 PMCID: PMC7462261 DOI: 10.1371/journal.pntd.0008721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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6
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Alzaylaee H, Collins RA, Shechonge A, Ngatunga BP, Morgan ER, Genner MJ. Environmental DNA-based xenomonitoring for determining Schistosoma presence in tropical freshwaters. Parasit Vectors 2020; 13:63. [PMID: 32051004 PMCID: PMC7017522 DOI: 10.1186/s13071-020-3941-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Accepted: 02/03/2020] [Indexed: 02/07/2023] Open
Abstract
Background Schistosomiasis is a neglected tropical disease that infects over 200 million people worldwide. Control measures can benefit from improved surveillance methods in freshwaters, with environmental DNA (eDNA) surveys having the potential to offer effective and rapid detection of schistosomes. However, sampling eDNA directly from natural water bodies can lead to inaccurate estimation of infection risk if schistosome eDNA is rare in the environment. Here we report a xenomonitoring method that allows schistosome infections of host snail species to be determined from eDNA in water used to house those snails. Methods Host snail species were collected and placed in containers of water and allowed to shed cercariae, and then water samples were filtered and tested using qPCR assays specific to the African species Schistosoma mansoni and Schistosoma haematobium. We evaluated this “eDNA-based xenomonitoring” approach by experimentally comparing the results to those obtained from direct qPCR screening of tissue sourced from the snails in the experiment. Results We found that our method accurately diagnosed the presence of S. mansoni-infected snails in all tests, and S. haematobium-infected snails in 92% of tests. Moreover, we found that the abundance of Schistosoma eDNA in experiments was directly dependent on the number and biomass of infected snails. Conclusions These results provide a strong indication that this surveillance method combining the utility of eDNA-based monitoring with the reliability of traditional xenomonitoring approaches could be used to accurately assay the presence of Schistosoma species in natural habitats. This approach may be well-suited for epidemiological studies and monitoring in endemic areas, where it can assist schistosomiasis control by indicating infection risk from freshwaters and guiding necessary interventions to eliminate the disease.![]()
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Affiliation(s)
- Hind Alzaylaee
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK.,Biology Department, Faculty of Sciences, Prince Nourah Bin Abdulrahman University, Riyadh, Saudi Arabia
| | - Rupert A Collins
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - Asilatu Shechonge
- Tanzania Fisheries Research Institute (TAFIRI), PO Box 9750, Dar es Salaam, Tanzania
| | - Benjamin P Ngatunga
- Tanzania Fisheries Research Institute (TAFIRI), PO Box 9750, Dar es Salaam, Tanzania
| | - Eric R Morgan
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK.,School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, UK
| | - Martin J Genner
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK.
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7
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Ford AG, Bullen TR, Pang L, Genner MJ, Bills R, Flouri T, Ngatunga BP, Rüber L, Schliewen UK, Seehausen O, Shechonge A, Stiassny ML, Turner GF, Day JJ. Molecular phylogeny of Oreochromis (Cichlidae: Oreochromini) reveals mito-nuclear discordance and multiple colonisation of adverse aquatic environments. Mol Phylogenet Evol 2019; 136:215-226. [DOI: 10.1016/j.ympev.2019.04.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 03/26/2019] [Accepted: 04/06/2019] [Indexed: 12/15/2022]
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8
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Shechonge A, Ngatunga BP, Tamatamah R, Bradbeer SJ, Harrington J, Ford AGP, Turner GF, Genner MJ. Losing cichlid fish biodiversity: genetic and morphological homogenization of tilapia following colonization by introduced species. CONSERV GENET 2018; 19:1199-1209. [PMID: 30363773 PMCID: PMC6182432 DOI: 10.1007/s10592-018-1088-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 07/09/2018] [Indexed: 11/04/2022]
Abstract
Among the many negative impacts of invasive species, hybridization with indigenous species has increasingly become recognized as a major issue. However, relatively few studies have characterized the phenotypic outcomes of hybridization following biological invasions. Here we investigate the genetic and morphological consequences of stocking invasive tilapia species in two water bodies in central Tanzania. We sampled individuals from the Mindu Reservoir on the Ruvu river system, and at Kidatu on the Great Ruaha-Rufiji river system. We screened individuals at 16 microsatellite loci, and quantified morphology using geometric morphometrics and linear measurements. In both the Mindu and Kidatu systems, we identified evidence of hybridization between indigenous Wami tilapia (Oreochromis urolepis) and the introduced Nile tilapia (Oreochromis niloticus) or blue-spotted tilapia (Oreochromis leucostictus). At both sites, purebred individuals could largely be separated using geometric morphometric variables, with hybrids occupying a broad morphospace among the parental species. Our data demonstrate that the gene pools and phenotypic identity of the indigenous O. urolepis have been severely impacted by the stocking of the invasive species. Given the lack of evidence for clear commercial benefits from stocking invasive tilapia species in waters already populated by indigenous congenerics, we suggest further spread of introduced species should be undertaken with considerable caution.
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Affiliation(s)
- Asilatu Shechonge
- Department of Aquatic Sciences and Fisheries, University of Dar es Salaam, P.O. Box 35064, Dar es Salaam, Tanzania
- Tanzania Fisheries Research Institute (TAFIRI), P.O. Box 9750, Dar es Salaam, Tanzania
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ UK
| | - Benjamin P. Ngatunga
- Department of Aquatic Sciences and Fisheries, University of Dar es Salaam, P.O. Box 35064, Dar es Salaam, Tanzania
| | - Rashid Tamatamah
- Department of Aquatic Sciences and Fisheries, University of Dar es Salaam, P.O. Box 35064, Dar es Salaam, Tanzania
- Tanzania Fisheries Research Institute (TAFIRI), P.O. Box 9750, Dar es Salaam, Tanzania
| | - Stephanie J. Bradbeer
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ UK
| | - Jack Harrington
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ UK
| | - Antonia G. P. Ford
- Department of Life Sciences, Whitelands College, University of Roehampton, Holybourne Avenue, London, SW15 4JD UK
| | - George F. Turner
- School of Biological Sciences, Bangor University, Bangor, Gwynedd LL57 2UW UK
| | - Martin J. Genner
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ UK
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9
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Bradbeer SJ, Harrington J, Watson H, Warraich A, Shechonge A, Smith A, Tamatamah R, Ngatunga BP, Turner GF, Genner MJ. Limited hybridization between introduced and Critically Endangered indigenous tilapia fishes in northern Tanzania. Hydrobiologia 2018; 832:257-268. [PMID: 30880834 PMCID: PMC6394572 DOI: 10.1007/s10750-018-3572-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 02/26/2018] [Accepted: 02/27/2018] [Indexed: 06/09/2023]
Abstract
Hybridization between introduced and indigenous species can lead to loss of unique genetic resources and precipitate extinction. In Tanzania, the Nile tilapia (Oreochromis niloticus) and blue-spotted tilapia (Oreochromis leucostictus) have been widely introduced to non-native habitats for aquaculture and development of capture fisheries. Here, we aimed to quantify interspecific hybridization between these introduced species and the indigenous species Oreochromis esculentus, Oreochromis jipe and Oreochromis korogwe. In the Pangani basin, several hybrids were observed (O. niloticus × O. jipe, O. leucostictus × O. jipe, O. niloticus × O. korogwe), although hybrids were relatively uncommon within samples relative to purebreds. Hybrids between the native O. jipe × O. korogwe were also observed. In the Lake Victoria basin, no evidence of hybrids was found. Analysis of body shape using geometric morphometrics suggested that although purebreds could be discriminated from one another, hybrids could not be readily identified on body and head shape alone. These results provide the first evidence of hybridization between the introduced species and the Critically Endangered O. jipe in Tanzania. Given uncertainty regarding benefits of introduced species over large-bodied indigenous species in aquaculture and capture fisheries, we suggest that future introductions of hybridization-prone species should be carefully evaluated.
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Affiliation(s)
- Stephanie J. Bradbeer
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ UK
- School of Biology, University of Leeds, Miall Building, Leeds, LS2 9JT UK
| | - Jack Harrington
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ UK
| | - Henry Watson
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ UK
| | - Abrahim Warraich
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ UK
| | - Asilatu Shechonge
- Tanzania Fisheries Research Institute (TAFIRI), P.O. Box 9750, Dar es Salaam, Tanzania
- Department of Aquatic Sciences and Fisheries, University of Dar es Salaam, P.O. Box 35064, Dar es Salaam, Tanzania
| | - Alan Smith
- Evolutionary and Environmental Genomics Group, School of Environmental Sciences, University of Hull, Hull, HU5 7RX UK
| | - Rashid Tamatamah
- Tanzania Fisheries Research Institute (TAFIRI), P.O. Box 9750, Dar es Salaam, Tanzania
- Department of Aquatic Sciences and Fisheries, University of Dar es Salaam, P.O. Box 35064, Dar es Salaam, Tanzania
| | - Benjamin P. Ngatunga
- Tanzania Fisheries Research Institute (TAFIRI), P.O. Box 9750, Dar es Salaam, Tanzania
| | - George F. Turner
- School of Biological Sciences, Bangor University, Bangor, Gwynedd, LL57 2UW UK
| | - Martin J. Genner
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ UK
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Shechonge A, Ngatunga BP, Bradbeer SJ, Day JJ, Freer JJ, Ford AGP, Kihedu J, Richmond T, Mzighani S, Smith AM, Sweke EA, Tamatamah R, Tyers AM, Turner GF, Genner MJ. Widespread colonisation of Tanzanian catchments by introduced Oreochromis tilapia fishes: the legacy from decades of deliberate introduction. Hydrobiologia 2018; 832:235-253. [PMID: 30880833 PMCID: PMC6394791 DOI: 10.1007/s10750-018-3597-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 03/09/2018] [Accepted: 03/16/2018] [Indexed: 06/09/2023]
Abstract
From the 1950s onwards, programmes to promote aquaculture and improve capture fisheries in East Africa have relied heavily on the promise held by introduced species. In Tanzania these introductions have been poorly documented. Here we report the findings of surveys of inland water bodies across Tanzania between 2011 and 2017 that clarify distributions of tilapiine cichlids of the genus Oreochromis. We identified Oreochromis from 123 sampling locations, including 14 taxa restricted to their native range and three species that have established populations beyond their native range. Of these three species, the only exotic species found was blue-spotted tilapia (Oreochromis leucostictus), while Nile tilapia (Oreochromis niloticus) and Singida tilapia (Oreochromis esculentus), which are both naturally found within the country of Tanzania, have been translocated beyond their native range. Using our records, we developed models of suitable habitat for the introduced species based on recent (1960-1990) and projected (2050, 2070) East African climate. These models indicated that presence of suitable habitat for these introduced species will persist and potentially expand across the region. The clarification of distributions provided here can help inform the monitoring and management of biodiversity, and inform policy related to the future role of introduced species in fisheries and aquaculture.
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Affiliation(s)
- Asilatu Shechonge
- Department of Aquatic Sciences and Fisheries, University of Dar es Salaam, P.O. Box 35064, Dar es Salaam, Tanzania
- Tanzania Fisheries Research Institute (TAFIRI), P.O. Box 9750, Dar es Salaam, Tanzania
| | - Benjamin P. Ngatunga
- Department of Aquatic Sciences and Fisheries, University of Dar es Salaam, P.O. Box 35064, Dar es Salaam, Tanzania
| | - Stephanie J. Bradbeer
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ UK
| | - Julia J. Day
- Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London, WC1E 6BT UK
| | - Jennifer J. Freer
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ UK
| | - Antonia G. P. Ford
- School of Biological Sciences, Bangor University, Bangor, Gwynedd LL57 2UW UK
- Department of Life Sciences, Centre for Research in Ecology, Whitelands College, University of Roehampton, Holybourne Avenue, London, SW15 4JD UK
| | - Jonathan Kihedu
- Tanzania Fisheries Research Institute (TAFIRI), P.O. Box 9750, Dar es Salaam, Tanzania
| | - Tabitha Richmond
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ UK
| | - Semvua Mzighani
- Tanzania Fisheries Research Institute (TAFIRI), P.O. Box 9750, Dar es Salaam, Tanzania
| | - Alan M. Smith
- Evolutionary and Environmental Genomics Group, School of Environmental Sciences, University of Hull, Hull, HU5 7RX UK
| | - Emmanuel A. Sweke
- Tanzania Fisheries Research Institute (TAFIRI), P.O. Box 9750, Dar es Salaam, Tanzania
| | - Rashid Tamatamah
- Department of Aquatic Sciences and Fisheries, University of Dar es Salaam, P.O. Box 35064, Dar es Salaam, Tanzania
- Tanzania Fisheries Research Institute (TAFIRI), P.O. Box 9750, Dar es Salaam, Tanzania
| | - Alexandra M. Tyers
- School of Biological Sciences, Bangor University, Bangor, Gwynedd LL57 2UW UK
| | - George F. Turner
- School of Biological Sciences, Bangor University, Bangor, Gwynedd LL57 2UW UK
| | - Martin J. Genner
- School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ UK
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