Abstract:
The water quality and fish populations of the Welland
River were observed to decline with distance downstream. This
coincided with increased agricultural , domestic and industrial
waste loadings. The river upstream of the City of Welland
received considerable loadings from agricultural sources.
Centrarchids, sciaenids, ictalurids, cyprinids and esocids
characterized this upper section of the river. Most of these
species were tolerant of low dissolved oxygen concentrations
and the high turbidity which prevailed there .
The river near Port Robinson receives many industrial
and domestic wastes as evidenced by the water quality data.
The fish in this section were less abundant and the observed
population was comprised almost solely of cyprinids. Further
downstream, near Montrose, the Welland River received shock
loads of chemical wastes that exceeded a specific conductance
of ISiOOO ;umhos/cm. Few fish were captured at this site and
those that were captured were considered to be transients.
A review of the literature revealed that none of the common
indices of water quality in use today could adequately predict
the observed distributions.
In addition to the above, the long-term trend (l3 yrs)
of water quality of the lower Welland River revealed a
gradual improvement. The major factor thought to be
responsible for this improvement was the operation of the
Welland Sewage Treatment Plant. The construction of the
New Welland Ship Canal coincided with large fluctuations of
the total solids and other parameters downstream. These
conditions prevailed for a maximum of three years (1972-
1975)' Furthermore, spawning times and temperatures,
geographic distributions, length-weight regressions and many
other descriptive aspects of the ecology of some 26 species/
taxa of fish were obtained. Several of these species are
rare or new to southern Ontario.
