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Martin Genner

@mgenner.bsky.social

1K followers 500 following 8 posts

Ecology and evolutionary biology, mainly fishes, climate change, conservation

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Martin Genner

@mgenner.bsky.social

JOB OPPORTUNITY! Senior Researcher in Freshwater Environmental Genetics to work with us on the ERC REFRESH Programme studying the role of dissolved organic matter in freshwater ecosystems shorturl.at/zOajg @pennyjohnes.bsky.social @bristoluni.bsky.social @ercrefresh.bsky.social @danread.bsky.social

A UK chalk stream with the water crowfoot in flow, and hemlock water dropwort on the bank.

One of the ERC REFRESH experiments underway. Experimental mesocosms are being used to study the biological responses to different forms of dissolved organic matter.

UK freshwater streams are rich in biological diversity, including damselflies such as this beautiful demoiselle

November 12, 2025 at 10:01 PM

Martin Genner

@mgenner.bsky.social

The Rift Valley soda lakes of Tanzania are warm and alkaline. The Manyara tilapia is one of the few fish species able to live here. New research suggests this one species may be two. One is found in Lake Manyara itself, the other is in neighbouring soda lakes. onlinelibrary.wiley.com/doi/10.1002/...

Lake Manyara, a soda lake in the Rift Valley of Tanzania

The Manyara tilapia, that has the Latin name Oreochromis amphimelas. This is an adult male, with the characteristic dark fins and pink tail. New research led by Miranda Sherlock and colleagues shows there two long-separated evolutionary lineages in the species, that may actually be cryptic species.

September 15, 2025 at 3:50 PM

Martin Genner

@mgenner.bsky.social

In crater Lake Masoko one fish species is splitting into shallow and deep-living ecotypes occupying different light environments. New research shows their visual systems are diverging, and how colours of male eggspots have changed to maximise their visibility. doi.org/10.1093/molb...

Lake Masoko in Southern Tanzania, also known as Lake Kisiba, is only ~40m deep and 600m in diameter. It was formed around 50,000 years ago, and is isolated from all nearby rivers and lakes. Genetic data suggest it was colonised by Astatotilapia calliptera around 10,000 years ago.

In Lake Masoko, Astatotilapia calliptera has two ecotypes. The shallow living "littoral" ecotype has yellowish males, while the deep living "benthic" ecotype has blueish males. Recently published research led by Madeleine Carruthers and colleagues shows how these fish occupy different light regimes, and have correspondingly different visual sensitivities. Males of these ecotypes have brightly coloured eggspots, used to signal their prowess. The colours of those spots have shifted to maximise their visibility to other fish of the same ecotype. Genetic data suggest these ecotypes are largely reproductively isolated, and started to separate only 1000 years ago. Photos are kindly provided by Ad Konings.

August 28, 2025 at 7:51 PM

Martin Genner

@mgenner.bsky.social

New research in Molecular Ecology shining light on the riverine ancestors of the Lake Malawi cichlid fish adaptive radiation, led by Sophie Gresham and Hannes Svardal doi.org/10.1111/mec....