what are the names of the fishes found in the watercourse?
Wild brown trout, chub and perch
Wildlife
wild brown trout 
where does the river welland start and finish The river rises in the Hothorpe Hills, at Sibbertoft in Northamptonshire, then flows generally northeast to Market Harborough, Stamford and Spalding, to reach The Wash near Fosdyke what is the total length of this watercourse? UNANSWERABLE what are some of its tributaries? UNANSWERABLE
Wild brown trout, grayling, chub, perch ,pike, perch, zander, roach, bream, rudd, ruffe, gudgeon and eels. Pike, perch, zander, roach, bream, rudd, ruffe, gudgeon and eels. Stamford, pike, perch, zander, roach, bream, rudd, ruffe, gudgeon and eels
River Welland River Welland River Welland
Wildlife Wildlife Wildlife
The river, in its upper reaches, supports a wild brown trout population and the occasional grayling. Chub and perch dominate the middle reaches around Stamford, with pike, perch, zander, roach, bream, rudd, ruffe, gudgeon and eels inhabiting the lower lengths around Spalding. The river, in its upper reaches, supports a wild brown trout population and the occasional grayling. Chub and perch dominate the middle reaches around Stamford, with pike, perch, zander, roach, bream, rudd, ruffe, gudgeon and eels inhabiting the lower lengths around Spalding.  Chub and perch dominate the middle reaches around Stamford, with pike, perch, zander, roach, bream, rudd, ruffe, gudgeon and eels inhabiting the lower lengths around Spalding.

wiki:1154801
River Welland [SEP] Wildlife
The river, in its upper reaches, supports a wild brown trout population and the occasional grayling. Chub and perch dominate the middle reaches around Stamford, with pike, perch, zander, roach, bream, rudd, ruffe, gudgeon and eels inhabiting the lower lengths around Spalding. A collaboration between the Welland Rivers Trust, the Wild Trout Trust and the Environment Agency has resulted in the construction of a rock ramp, to allow migrating sea trout to pass up the river beyond the weir on the Maxey Cut, which was acting as a barrier. Some 300 tons of rock, with 50 tons of finer material forming a top layer, were used to create the ramp.