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**
**www.uwpmag.com nr 94 pg 42 46