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content@managingwater.co.uk Conservation & the Environment Killer


Shrimps found in the Broads


The Environment Agency, Natural England and the Broads Authority have been working together to investigate the presence of the shrimp, Dikerogammarus villosus, in Barton Broad.


Andrea Kelly Senior Ecologist for the Broads Authority said: ‘The shrimp were found through a dedicated monitoring programme. Fortunately we’ve only found the shrimp in a very localised area in the Broads so far. People checking, cleaning and drying their equipment after use is essential to help stop the spread of all non-native species and we would really appreciate their full cooperation in doing this. ‘We are working with our partners to investigate the shrimps’ current population and range in the Broads and to investigate and implement measures to limit its spread to and from other water courses. There is no risk to the public or their pets from it.’


Dikerogammarus villosus, commonly known as ‘killer shrimp’, is an invasive non-native species. If the shrimp became established and widespread, as other invasive species such as floating pennywort and Signal crayfish have, it could threaten populations of native species. Although the shrimp only grows to a maximum of 30mm (11/4 inches) it feeds on insect life including our native species such as damselfly nymphs, water boatmen and small fish.


The Check Clean Dry campaign asks all water users to take simple steps to help prevent the spread of non-native species between rivers, lakes and reservoirs. Clothing and equipment that has come in contact with the water should be checked for any living organisms and then thoroughly washed-down. Any organisms found should be returned to the water body they came from. Equipment and clothing should be dried as some species can survive for days in damp conditions.


Invasive Plants - ‘Algal


Bloom is a naturally occuring plant, but can


become harmful if certain


conditions prevail’


What is Algal Bloom? and how is it identified?


An algal bloom is a rapid increase or accumulation in the population of algae (typically microscopic) in an aquatic system.


Blooms can occur in freshwater as well as marine environments.


Typically, only one or a small number of phytoplankton species are involved, and some blooms may be recognized by discoloration of the water resulting from the high density of pigmented cells.


Although there is no officially recognized threshold level, algae can be considered to be blooming at concentrations of hundreds to thousands of cells per milliliter, but can reach millions of cells per milliliter.


Algal blooms are often green, but they can also be other colors such as yellow-brown or red, depending on the species of algae. Bright green blooms are a result of cyanobacteria (colloquially known as blue-green algae) such as Microcystis. Blooms may also consist of macroalgal (non-phytoplanktonic) species. These blooms are recognizable by large blades of algae that may wash up onto the shoreline.


Of particular note are harmful algal blooms (HABs), which are algal bloom events involving toxic or otherwise harmful phytoplankton such as dinoflagellates of the genus Alexandrium and Karenia, or diatoms of the genus Pseudo- nitzschia. Such blooms often take on a red or brown hue and are known colloquially as red tides.


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