News

Sundial spotlight: freshwater shrimp

Freshwater shrimp

The third in a series of blogs celebrating the flora and fauna of our local river. 

By Jenny Figueiredo

The Freshwater Shrimp, Gammarus pulex, is one of those fairly self-explanatory names for a creature – simply a shrimp that lives in fresh water.  The common freshwater shrimp has a robust appearance, and is typically greyish with markings in dark brown or green. Seafood fans will be disappointed to hear that it’s unlikely you would throw any of Osney’s shrimps ‘on the barbie’ – most common freshwater shrimp vary in length between a pretty tiny 14mm for females to 21mm for males. 

As well as rivers and canals, freshwater shrimp can sometimes be found in garden ponds as well as in rivers and canals, as they are frequently carried as eggs or tiny babies on the feet of birds. 

These miniature marvels played a starring role in the campaign back in the 1880s to provide fresh water to Oxford.   When a new pumping station was installed in Oxford (in Lake Street, where South Oxford Community Centre now stands), local social campaigner and famous photographer Henry Taunt challenged the mayor to prove that the water pumped from New Hinksey Lake was fit to drink.  Taunt himself had claimed that in less than three hours of running the city water from his household tap, he had caught no fewer than 37 freshwater shrimps, which he later displayed at Oxford Town Hall under a microscope.

Photo credit: AJ Cann

Photo credit: AJ Cann

In recent years our friendly native freshwater shrimps are being increasingly challenged by invasive, non-native species.  These include the rather ominously named ‘Demon Shrimp’ (Dikerogammarus haemobaphes), which is one of the 15 invasive non-native species of most concern to the Environment Agency to be found here in Oxfordshire (according to Wild Oxfordshire’s ‘State of Nature’ report in 2016).  These invasive species tend to reproduce more quickly, are omnivorous and have a better tolerance for a range of temperature, salt and pollution levels than the native kinds.   As a result they are highly successful invaders and can be sadly very disruptive to ecosystems.

This mosaic has been commissioned in celebration of our centuries old relationship with the river. Local artist Josie Webber has created designs featuring native species nominated by local residents, and incorporating pottery fragments found in West Oxford. The marker stones will form part of a human sundial to be installed on the site. This project has been made possible thanks to the support of the National Lottery Heritage Fund.mosaic1_white