Environmental Engineering Reference
In-Depth Information
TFM and niclosamide
TFM has been used in the USA since 1958 either singly or in combination with
niclosamide (Bayluscide®) after 1963 to selectively poison sea lamprey ammo-
coete larvae in tributaries of the Great Lakes. TFM formulations include a liquid
concentrate, which is applied by boat or backpack sprayers, and solid block, which
is secured in a stream and allowed to dissolve slowly. TFM toxicity to lamprey
larvae is signifi cantly greater than to other fi shes and aquatic life, however, unlike
the other toxicants profi led here, TFM detoxifi es only very slowly in the environ-
ment. Marking and Olsen (1975) found little or no loss of activity after 8 weeks.
Niclosamide formulations include a wettable powder and granular products.
Niclosamide toxicity varies with species. It is highly toxic to aquatic molluscs, more
so than to most fi shes, and is also used as a selective molluscicide. The sea lamprey
control programme has been highly successful and by 1972, catches of spawning
sea lamprey in Lake Superior had declined by 92% (Heinrich et al . 2003). Average
annual TFM usage was around 34 t in the period 1995-1999 (McDonald and
Kolar 2006).
13.8.2.3 Biocontrol measures
Most potential biocontrol measures are still considered experimental or hypo-
thetical rather than effective and readily available control tools. Advancements in
the biological control of aquatic species are considerably less developed and more
problematic than counterparts in terrestrial biocontrol (Secord 2003).
Predatory fi sh
Although the introduction of a large predatory species may seem intuitively
appealing for controlling nuisance fi sh this is unlikely to be effective given the
relatively non-selective feeding of most fi sh. Introductions of large-bodied exotic
piscivorous species have generally caused signifi cant ecological problems (e.g. Nile
perch in Lake Victoria), and many countries lack indigenous large-bodied pisci-
vores. Natural predator-prey dynamics mean that a predatory species is unlikely
to completely eliminate its prey thereby reducing the effectiveness of biocontrol.
However, the introduction of the piscivorous European perch ( Perca fl uviatilis )
to some New Zealand lakes has completely eradicated all other fi sh species, to the
signifi cant detriment of indigenous biodiversity.
Pheromones
Pheromone traps have proved to be highly effective in pest control and biosurveil-
lance, particularly for insects, and this is a developing area of research for invasive
fi sh control. Field trials of sea lamprey pheromone (Li et al . 2007) demonstrate the
potential to use pheromones to enhance the capture of nuisance fi sh, and as a tool
to detect pest-fi sh incursions, especially given the extreme sensitivity of some fi sh
species to pheromonal compounds. Pheromones offer potential for sex-specifi c
and species-specifi c removal, and for reproductive disruption (Sorensen and Stacey
 
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