FRESH Perspectives

Curated by a different #PhD student from the @GW4FreshCDT programme every week. Home to a variety of perspectives on #freshwater #research as it happens.

[Toby Champneys @ChampneysToby]

View from my hotel room here in Dar es Salaam. Looking forward to finally seeing my study species in its 'natural' habitat #invasivespecies #fieldwork

[Jack Greenhalgh @WildAudioJack]

Last week I was at the @norfolkponds #Big50 #pond #restoration event.
These sounds, recorded in restored ponds (right), show the diversity of life that is capable of returning to neglected ponds (left) after restoration.

Photos: @uclpond #bioacoustics
https://t.co/DVQID4O0TS

[Eleri Pritchard @Eleri_Pritchard]

I would love to hear from other PhD students/academics working on #signal #crayfish. If there was enough interest perhaps even set up a working group or platform for communication/collaboration. #AcademicTwitter can you help me find them?! #phdchat #invasivespecies

[FRESH Perspectives @FRESHPerspectii]

During my PhD, as a member of the fantastic https://t.co/FfwNcIC5tJ I can apply the latest techniques in collective animal behaviour through which I hope to provide new perspectives on the impact of Nile tilapia on native ecosystems and the mechanisms that drive such effects.

[FRESH Perspectives @FRESHPerspectii]

Unlike Nile Perch which is a top-level predator, Nile tilapia are mostly microphagous and the mechanisms through which they effect native ecosystems are not always obvious...

Canonico et al., 2005 summarised the leading evidence in this great review: https://t.co/tNw72weM1y

[FRESH Perspectives @FRESHPerspectii]

The academy award nominated documentary "Darwin's Nightmare" covers the harmful socioeconomic affects that followed the introduction of Nile perch to Lake Victoria.

Increased poverty and food shortages were felt within the region, and local inhabitants were displaced.

[FRESH Perspectives @FRESHPerspectii]

Nile tilapia are not the only invasive species that have affected freshwater ecosystems in Tanzania.

The Nile perch and Water hyacinth are two other prominent examples from Lake Victoria that have had devastating impacts far beyond the loss of biodiversity.

[FRESH Perspectives @FRESHPerspectii]

The Nile Perch was intentionally introduced to Lake Victoria in 1954, with the aim of boosting local fisheries.

What followed is one of the worst vertebrate extinctions in recent times. Hundreds of native cichlids were driven to extinction, and the lake became eutrophic.

[FRESH Perspectives @FRESHPerspectii]

This brilliant figure from Zengeya et al., 2013 shows how Nile tilapia have spread outside their native range within Africa.

Tomorrow I will go on to discuss the effect of invasive tilapia, and a brief history of invasive species impacts in Tanzania!

https://t.co/KhpWRmX3m3

[FRESH Perspectives @FRESHPerspectii]

This is the Nile tilapia

In 2016 more than 4 million tonnes were produced, across more than 100 countries. Nile tilapia are an ideal species for aquaculture production due to their:

- Wide environmental tolerance
- High fecundity
- Broad diet
- Fast growth rate

[FRESH Perspectives @FRESHPerspectii]

However...

The very characteristics that make Nile tilapia well suited for aquaculture, also make them a species with very high invasive potential...

...and Nile tilapia have now established non-native populations almost everywhere they have been cultured.

[FRESH Perspectives @FRESHPerspectii]

The unprecedented diversity in these lakes results from the adaptive radiation of Cichlid fishes (see: https://t.co/kj6HsR9JTM for a great overview).

They are now renowned for their rapid speciation and incredible taxonomic, morphological, ecological, and behavioural diversity.

[FRESH Perspectives @FRESHPerspectii]

The freshwater ecosystems in East Africa are huge:

Here's a size comparison between Lake Victoria and Loch Ness...

https://t.co/6tMQKffEXa

[FRESH Perspectives @FRESHPerspectii]

They are also incredibly biodiverse, lets look at another comparison:

In all of UK freshwater there are 54 species of fish

In Lakes Victoria, Malawi, Tanganyika etc. there are a LOT more

Check out this table from Turner et al., 2001 https://t.co/shXNgBUBeR

[FRESH Perspectives @FRESHPerspectii]

@punkloch I think you're right! Here's the graphic

[FRESH Perspectives @FRESHPerspectii]

Hello, im @ChampneysToby and my PhD project aims to use techniques in behavioural ecology to better understand the impacts and risks of #invasive tilapia in Tanzania

Here's an overview of what i'll be tweeting about this week

[FRESH Perspectives @FRESHPerspectii]

This week, FRESH Perspectives is curated by @ChampneysToby from @BristolBioSci.

[Penny Johnes @pj13302]

Fantastic day at #gw4wsa2019 conference today with interactive discussions between @NERCscience @GW4FreshCDT, @EPSRC @WISECDT PhD students, stakeholders from policy to research and industry, and @GW4 academic researchers

[GW4 Fresh CDT @GW4FreshCDT]

Congratulations to Fiona Joyce for winning best poster at the @Gw4Water Security Alliance conference.