Vol. 15—1961 - NorthEastern Weed Science Society

. CHEMICALCONTROLOF AQUATICVEGETATION
IN RELATIONTO THECONSERVATIONOF FISH ANDWILDLIFE
G. E. Burdick, Sr. Aquatic Biologist
N.Y•S. Conservation Department
In 1959 the NewYork Water Pollution Control Board issued permits for
chemical control of vegetation for more than 1900 acres of water, distributed
over lakes and ponds with a combined acreage of nearly 15,000 acres. This
represents only part of the water area treated in this State, since the regulations
exclude from the necessity of obtaining a permit water supply agencies
treating their sources of supply and parties treating ponds with no outlet
which lie within the lands of a single owner. It is also suspected that many
waters are being treated in ignorance of the necessity to obtain a permit •
• These permits were issued for the treatment of marginal areae only, since the
available information was inadequate for the evaluation of the primary and
secondary effects on aquatic resources. A great deal of research is necessary
on the effects of chemical methods in order that they may be used to increase
the recreational value of waters with the minimmn of adverse effect on
fish and wildlife. Uncontrolled use to remove ~ vegetation from waters is
ill-advised and can create a grave pressure against our already dwindling
aquatic resources of fish and wildlife.
Importance
of vegetation:
The dependence of animal life on plants is just as.great in water as on
land, possibly even greater. In the absence of rooted aquatics, algae, diatoms
and bacteria, the existence of fish and the forma on which they feed
would be impossible. No one would consider de straying all vegetction and
then turning in stock to feed, yet too often that is attempted in aquatic
pastures. It is fortunate that ma01 of the chemicals now in use are not too
highly efficient.
During the Allegheny-Chemung Biological Survey (1937) a comprehensive
study was made of the bottom food in a bay of Chautauqua Lake. On a line extending
lakeward, the nmnber and extent of the weedbeds were plotted and the
plants. .oompoedng them identified. In the shallow water zone (0 to 6 foot
dep.th),.seven weedbeds and seven weedless areas were found to cover a distance
of abou~97 meters. The quantitative average of the food present in each
area'h.as.been multiplied by its extent, added, and divided by the distance
covsredTn meters. This gives the average production in each category. The
weedless :area averaged 32.3 g/m2 (grams per square meter), while the weeded
sections a.veraged 169.2 g/m 2• The weeded areas thus contained 5.23 times the
food organisms available in the weed1ess areas. Based on the comparative
dimensions of the areas and assmning that production in the weed1ess zones
would be uniform on removal of weeds, it CAn be computed that the px'esen~ of"