Low genetic diversity and lack of genetic structure among populations of the sandfish <i>Holothuria (Metriatyla) scabra</i> on the Tanzanian coast

Bugota, Valeli J.; Rumisha, Cyrus

doi:10.1080/17451000.2023.2176883

Cited by 2 publications

(1 citation statement)

References 37 publications

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“…Each extraction step was performed according to the manufacturer's protocol. To avoid cross contamination, scissors and other equipment were rinsed with ethanol and ignited with a lighter between each step (Bugota & Rumisha, 2022). Prior to DNA amplification, the quality of the DNA extracts was checked on a 1% agarose gel, and the eluted DNA extracts were stored at −20°C for further analysis.…”

Section: Methodsmentioning

confidence: 99%

Lack of mitochondrial introgression and limited genetic connectivity among Manyara tilapia (Oreochromis amphimelas) populations in Tanzanian Saline Rift Valley Lakes

Morandus,

Rumisha

2024

Afr J Ecol

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The Manyara tilapia (Oreochromis amphimelas), native to the Saline Rift Valley Lakes (SRVLs) in north‐central Tanzania, has recently experienced population declines mainly due to overfishing and severe droughts. This, combined with the introduction of Nile tilapia (O. niloticus), which poses a risk of hybridisation, could potentially erode essential genetic traits necessary for their survival. To address these concerns, our study analysed partial cytochrome oxidase subunit I sequences (627 base pairs) from 139 Manyara tilapia and 79 Nile tilapia specimens collected from the SRVLs to test two hypotheses: (i) whether there is no transfer of mitochondrial DNA between these species, and (ii) whether Manyara tilapia populations in the SRVLs have remained genetically connected despite reported declines. The results revealed six distinct haplotypes for Manyara tilapia and three for Nile tilapia. These haplotypes formed separate clusters for each species, with no shared or closely related haplotypes, indicating limited or no transfer of mitochondrial DNA between them. Additionally, we found evidence of restricted genetic connectivity among Manyara tilapia populations in the SRVLs, with populations in Lakes Manyara and Eyasi displaying limited genetic exchange among themselves and with those in other SRVLs. Our findings highlight the importance of sustained conservation efforts in protected areas around Lake Manyara and Lake Eyasi to safeguard the unique populations of Manyara tilapia in these lakes. However, limited connectivity with other SRVLs suggests that conservation initiatives in these areas may have a limited impact on these lakes. Thus, future efforts should prioritise stocks in Lakes Kindai, Singida and Sulunga, focusing on protecting fish refugia, particularly the rivers connected to these lakes, which serve as critical habitats during the dry season and as important reservoirs for replenishing these populations.

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Section: Methodsmentioning

confidence: 99%

Lack of mitochondrial introgression and limited genetic connectivity among Manyara tilapia (Oreochromis amphimelas) populations in Tanzanian Saline Rift Valley Lakes

Morandus,

Rumisha

2024

Afr J Ecol

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Unveiling interconnectedness between marine protected and non‐protected areas in Tanzania: Insights from barred mudskipper (Periophthalmus argentilineatus) population genetic structure

Rumisha

2024

Fisheries Management Eco

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Marine protected areas (MPAs) are globally recognised for their role in safeguarding marine fisheries from the detrimental impacts of human activities and climate change. Tanzania, in alignment with global conservation efforts, has designated 18 MPAs and plans to establish four more in the Southwestern Indian Ocean. However, a critical challenge arises from the lack of a thorough understanding of genetic connectivity between populations in MPAs and non‐protected areas (NPAs). To address this, 151 mitochondrial D‐loop sequences (357 base pairs) of Barred mudskipper (Periophthalmus argentilineatus) were analysed to assess genetic connectivity between MPAs and NPAs in Tanzania. The findings revealed a low and insignificant index of genetic differentiation (FST = −0.0046, p > 0.05) between populations in MPAs and NPAs. Furthermore, haplotypes from both MPAs and NPAs did not cluster based on their geographical origins, with over 9 haplotypes shared between these areas. Additionally, the measured haplotype and nucleotide diversities did not differ significantly between MPAs and NPAs (p > 0.05). However, MPAs showed a significantly higher number of private haplotypes compared to NPAs (p < 0.05). These findings suggest high genetic interconnectedness between populations in MPAs and NPAs, underlining the importance of existing MPAs in preserving local genetic diversity and their potential to replenish depleted NPAs. However, realising the full potential of this interconnectedness necessitates stringent enforcement of sustainable fishing practices to alleviate pressure on fish stocks. It also requires the protection of critical habitats that serve as corridors for fish dispersal, facilitating interconnectedness between MPAs and NPAs.

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Low genetic diversity and lack of genetic structure among populations of the sandfish Holothuria (Metriatyla) scabra on the Tanzanian coast

Cited by 2 publications

References 37 publications

Lack of mitochondrial introgression and limited genetic connectivity among Manyara tilapia (Oreochromis amphimelas) populations in Tanzanian Saline Rift Valley Lakes

Lack of mitochondrial introgression and limited genetic connectivity among Manyara tilapia (Oreochromis amphimelas) populations in Tanzanian Saline Rift Valley Lakes

Unveiling interconnectedness between marine protected and non‐protected areas in Tanzania: Insights from barred mudskipper (Periophthalmus argentilineatus) population genetic structure

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