9646

• UCREFRP Catalog Number: 9646
• Author: Wiley, R. W. and R. S. Wydoski.
• Title: Management of Undesirable Fish Species.
• USFW Year: 1993.
• USFW - Doc Type: 335-354
• Copyright Material: YES

UNDESIRABLE SPECIES

343

compound that was formerly availablc. Some biologists apply the liquid to sand to
treat deep lakes and ponds.

14.4.5.3 Lampricides

Two lampricides, TFM (3-triflouromethyl-4-nitrophenol) and Bayluscide
(Baycr 73) are currently registered in the United Statcs. Both toxicants are used
only in control of the sea lamprey, largely by the Great Lakes Fishery Commis-
sion (see Chapter 22).

TFM. This selective toxicant, which was first tested as a lampricide in
Michigan in 1958 (Cumming 1975), is applied as a liquid or soluble bar formulation
to control larval lampreys (ammocetes) in spawning and nursery areas. The mode
of action is not well understood but TFM appears to cause general collapse of the
circulatory system. The toxicant TFM is restricted for nonfood use as a lampri-
cide and can be used only by applicators certified by the Fish and Wildlife Service
(Schnick et al. 1986). The effectiveness of TFM is depressed at water tempera-
tures near freezing and at pH values above 8.0. The chemical is environmentally
nonpersistent, does not affect birds, mammals, or aquatic plants (though photo-
synthesis may be reduced), has a varied affect on invertebrates depending upon
treatment location and species, and may depress associated fish populations.

Bayluscide (Bayer 73). Bayluscide is a granular or powdered toxicant that was
developed for the control of mollusks (snails) in tropical areas and first used as a
lampricide in 1963 (Cumming 1975). The mode of action of Bayluscide is thought
to be similar to that of TFM, but the exact mode is unknown (National Research
Council of Canada (985). Bayluscide is registered as a survey tool for sea lamprey
populations and the synergistic combination of Bayluscide-TFM (not more than
2% TFM by weight) is registered as a lampricide. A formulation applied to sand
has been found effective for control of larval lamprey , especially at the mouths of
rivers entering lakes.
Although Bayluscide is used as a lampricide, it is highly toxic to associated
fishes and must be used with care. The compound is environmentally nonpersis-
tent, is pH-sensitive, moderately toxic to mammals, and very toxic to mollusks
and aquatic annelids.

14.4.6 Evaluation of Chemical Control of Undesirable Fishes

Cost-benefit information on the chemical control of fishes is not readily
available. Numerous states report annually spending large sums to control
undesirable fish stocks but few have summarized actual cost-benefit data. The
cost per hectare to treat with rotenone ranged from $2.00 to $240.00 and averaged
$40.00 in the late 1980s. Costs varied in relation to volume of water treated.
Rotenone is such an important fish toxicant than the expenditure of nearly $3
million and investment of 6 years of testing were justified to reregister the toxicant
for fishery use (Sousa et aI. 1987).
Information on costs associated with other registered fish toxicants is not
adequate to permit comparisons. Much time and money have been invested in the
control of sea lamprey in the Great Lakes. The increase in the number of lake
trout is, at least partly, attributable to chemical control of the sea lamprey. It