๐๐ฐ๐ฑ! In biology, I am a genus of amphipod crustacean in the Gammaridae family. I live in lakes and rivers up to 1300m altitude, I have seven pairs of legs in total, I am very sensitive to pollution, sometimes called ditch crab, ๐ท๐ฒ ๐๐๐ถ๐ ๐น'๐ฎ๐ป๐ถ๐บ๐ฎ๐น ๐ฑ๐ฒ ๐น'๐ฎ๐ป๐ป๐ฒฬ๐ฒ ๐ฎ๐ฌ๐ฎ๐ญ ๐ฃ๐ฟ๐ผ ๐ก๐ฎ๐๐๐ฟ๐ฎ, I am... ?
๐๐ฒ ๐๐ฎ๐บ๐บ๐ฎ๐ฟ๐ฒ ๐ฑ๐ฒ๐ ๐ฟ๐๐ถ๐๐๐ฒ๐ฎ๐๐ (๐๐ฎ๐บ๐บ๐ฎ๐ฟ๐๐ ๐ณ๐ผ๐๐๐ฎ๐ฟ๐๐บ) ๐ฒ๐๐ ๐๐ป ๐ฝ๐ฒ๐๐ถ๐ ๐ฐ๐ฟ๐๐๐๐ฎ๐ฐ๐ฒฬ (less than 2cm) with a curved body, rather like a crescent. Its back is covered by an articulated carapace. In addition to its seven pairs of legs, it has two pairs of antennae, other smaller appendages and bristles everywhere. Its colour varies between brown, grey and green, depending on the water, food and age.
Far from being confined to watercourses, the Brook Gammarus can be found in all types of surface and groundwater. . ๐๐น ๐๐ถ๐ ๐ฒฬ๐ด๐ฎ๐น๐ฒ๐บ๐ฒ๐ป๐ ๐ฑ๐ฎ๐ป๐ ๐น๐ฒ ๐๐ฒฬ๐บ๐ฎ๐ป where up to several thousand individuals can be found per square metre.
The Brook Gammary has what scientists call a "species complex". This means that ๐ฑ๐ฒ๐ ๐ถ๐ป๐ฑ๐ถ๐๐ถ๐ฑ๐๐ ๐ฎฬ ๐ฝ๐ฟ๐ถ๐ผ๐ฟ๐ถ ๐ฝ๐ฎ๐ฟ๐ณ๐ฎ๐ถ๐๐ฒ๐บ๐ฒ๐ป๐ ๐๐ฒ๐บ๐ฏ๐น๐ฎ๐ฏ๐น๐ฒ๐, ๐ฎ๐ฝ๐ฝ๐ฎ๐ฟ๐๐ถ๐ฒ๐ป๐ป๐ฒ๐ป๐ ๐ฎฬ ๐ฑ๐ฒ๐ ๐ฒ๐๐ฝ๐ฒฬ๐ฐ๐ฒ๐ ๐ฑ๐ถ๐ณ๐ณ๐ฒฬ๐ฟ๐ฒ๐ป๐๐ฒ๐ ๐๐๐ฟ ๐น๐ฒ ๐ฝ๐น๐ฎ๐ป ๐ด๐ฒฬ๐ป๐ฒฬ๐๐ถ๐พ๐๐ฒ. Gammarus? fossarum types A, B and C have been identified (only A and B have been found in Lake Geneva).
๐๐ฒ๐ ๐๐ฟ๐ผ๐ถ๐ ๐ฒ๐๐ฝ๐ฒฬ๐ฐ๐ฒ๐ ๐ป๐ฒ ๐๐ผ๐ป๐ ๐ฝ๐ฎ๐ ๐น๐ฒ๐ ๐๐ฒ๐๐น๐ ๐ด๐ฎ๐บ๐บ๐ฎ๐ฟ๐ฒ๐ ๐ฝ๐ฟ๐ฒฬ๐๐ฒ๐ป๐๐ ๐ฑ๐ฎ๐ป๐ ๐น๐ฒ ๐น๐ฎ๐ฐ. The Amphipod.CH project has also identified other species, both native and indigenous. To recognise them, they have developed an online identification key that can be easily used on the InfoFauna.
All these species play an important role in ecosystem processes. In other words, ๐ถ๐น๐ ๐ณ๐ผ๐ฟ๐บ๐ฒ๐ป๐ ๐๐ป ๐บ๐ฎ๐ถ๐น๐น๐ผ๐ป ๐ถ๐บ๐ฝ๐ผ๐ฟ๐๐ฎ๐ป๐ ๐ฑ๐ฒ ๐น๐ฎ ๐ฐ๐ต๐ฎ๐ถ๐ป๐ฒ ๐ฎ๐น๐ถ๐บ๐ฒ๐ป๐๐ฎ๐ถ๐ฟ๐ฒ ๐พ๐๐ถ ๐๐ถ๐ฒ๐ป๐ ๐ฒ๐ป ๐ฒฬ๐พ๐๐ถ๐น๐ถ๐ฏ๐ฟ๐ฒ ๐น'๐ฒฬ๐ฐ๐ผ๐๐๐๐๐ฒฬ๐บ๐ฒ ๐ฑ๐ ๐น๐ฎ๐ฐ. What's more, as the Brook Gammary is particularly sensitive to pesticides and sewage, i๐น ๐ฒ๐๐ ๐๐๐ถ๐น๐ถ๐๐ฒฬ ๐ฒ๐ป ๐ฒฬ๐ฐ๐ผ๐๐ผ๐ ๐ถ๐ฐ๐ผ๐น๐ผ๐ด๐ถ๐ฒ ๐ฐ๐ผ๐บ๐บ๐ฒ ๐ถ๐ป๐ฑ๐ถ๐ฐ๐ฎ๐๐ฒ๐๐ฟ ๐ฑ๐ฒ ๐น๐ฎ ๐ฝ๐ฟ๐ผ๐ฝ๐ฟ๐ฒ๐๐ฒฬ ๐ฑ๐ฒ๐ ๐ฒ๐ฎ๐๐ .
Threatened by pollutant discharges, these small crustaceans are also under threat from a cousin species from the Danube known as the ๐น๐ฎ ๐ฐ๐ฟ๐ฒ๐๐ฒ๐๐๐ฒ ๐๐๐ฒ๐๐๐ฒ (Dikerogammarus villosus). Larger (approx. 3cm), this species attacks other aquatic amphipods. However, it is completely harmless to humans.
Photo credits :
๐ Pro Natura, The Brook Gammary is Animal of the Year 2021
๐ Altermatt F, Alther R, Fiลกer C, Jokela J, Konec M, Kรผry D, et al. (2014) Diversity and Distribution of Freshwater Amphipod Species in Switzerland (Crustacea: Amphipoda). PLoS ONE 9(10)
๐ Amphipod.ch
๐ Fauna.eu
