5. Jan, 2017

Freshwater species: the wonder of our streams and rivers.

There was a time not so long ago when the small ditches and canals of the Dutch countryside, as well as those in the vicinity of  cities  were  teeming with stickleback, pike, bream  and perch. There were salamanders, frogs  and among the duckweed  on the surface of the crystal clear water one could find frog spawn in spring,  and water spiders darting in all directions.  Along the edges in the reed beds there were  damselflies,  dragonflies and occasionally a white heron or even a kingfisher waiting for its prey.  Little boys went out with their  small fishing nets to catch stickelbacks for their aquarium. Frog eggs were taken home  to  observe how they hatched  into tadpoles with their  wagging long tails and gills. Among the pictures of  heroic  events in Dutch history that  often decorated our classrooms,  one could also find   reproductions of nature painter  Marinus Adrianus Koekoek depicting these wonderful species in their environment (see insert above).

It is a sad and common  truth that not much  is left of this small and beautiful  world under the waterline. At least not in the vicinity of the big cities. The deteriorating water quality is the main reason why the number of fresh water species has diminished rapidly in the last fifty years. This holds in particular for larger species on top of the food chain like the pike and the otter. Invasive plants like the parrot feather that grow abundantly in our climate  treathen to clog irrigation canals and small rivers. The inland  habitats of fresh water species  are  more  vulnerable and treathened  by pollution than  those of species living  in  the great oceans.  In the UK the situation seems to be  not  very  different from that in Europe. In particular the  agricultural areas seem to suffer most from pollution of cattle and pesticides that penetrated the ground water. Most heavily polluted are the big rivers in the industrial areas. According to  recent  government's ecological assessment of water quality  more  than than three-quarters of  the waters in the UK seem unable to meet the  new European quality standards.*

The good news is that in  less densily populated counties in the UK  with fast flowing rivers, pristine pools and shallows  one can still find salmon and  trout. Here (and to some extent also in similar areas in Holland)  one can still  find  the  stickleback, pike, perch, trout, bream, tench, mullet, carp and  bitterling. And even more rare species such as  the rainbow trout  and the almost extinct lamprey that are now returning to their old habitats. Some nature photographers  have been able  to capture  these species  in the wild  with amazing  images as a result. A good example is the book  Freshwater Fishes of Britain published by Jack  Perks, that  covers almost every British species,  and will certainly  appeal to both naturalists and anglers across the country**


* https://www.theguardian.com/environment/2016/jan/15/englands-waters-to-remain-illegally-polluted-beyond-2021

**www.uwpmag.com  nr 94 pg 42 46