Video of electro-fishing survey
Posted on October 06, 2014
Electro-fishing surveys are an important tool in fisheries management, allowing the collection of data on fish numbers and sizes, and scale samples for further analysis such as age and genetics.
The surveys also give valuable insights into the habitat that trout occupy – particularly when escaping from predation!
The video below shows an electro-fishing survey carried out by the Hull International Fisheries Institute on the River Don in Sheffield following Ranunculus (water crowfoot) planting by volunteers. It is a fascinating exercise to show just how many fish were living in a short reach, and how the recently planted Ranunculus provided cover for fish.
Read Paul Gaskell’s blog post for more information both on the Ranunuclus planting project and how habitat complexity helps shift the balance from predators like fish eating birds in favour of the fish.
How to plant Ranunculus in a spate river ? Creative use of ladies stockings, plastic guttering and rocks required ! This is the method, developed by Dave Woodhead of SPRITE:
Build a sandwich of riverbed gravel, silt and Ranunculus root mass on a section of plastic guttering. Then slide the open end of a cut down stocking leg over the gutter.
Slide the gutter out leaving the root and substrate inside and tie around the outside of the stocking with another strip of material, an inch or two behind the open end, leaving the long green fronds of the foliage trailing.
Dig a depression and shove the root mass and substrate sausage into it and then lay rocks over the top to anchor.
The roots are protected and nourished and soon break out through the fabric. Fairly resistant to bird grazing too.
See also the video below