Interesting paper from B.C. MOE on invasive species management,
http://stopstocking.cowyafs.org/out...anagementstrategiesforillegallyintroduced.pdf
It's a bit of a long read but worth taking the time.
Thanks for the link to the BC MOE document regarding managing invasive species Quin. The quote below is from the BC MOE document Quin posted several posts back.
Native-Non-native Fisheries Species Interactions
In BC, there are concerns that non-native species may compromise native fish stocks and
attendant fisheries. However, I reviewed a number of studies investigating the predator-prey interactions between non-native fishery species and salmonids and found
that, in general, direct predation on salmonids by introduced species was not significant.
For example, with respect to suspected predation by smallmouth bass on salmonids, a
number of studies found only minimal predation and only when concentrations of
smallmouth bass and salmonids overlapped significantly in time and space (Table 8)
(Warner, 1972; Pflug and Pauley, 1983). Moreover, in their investigation of predation by
smallmouth bass on sockeye smolts, Fayramand Sibley (2000) found that bass have
limited consumption of sockeye during February-April when the salmon fry enter the
lake because the low water temperature severely limits smallmouth bass feeding (Scott
and Crossman, 1973). In effect, migrating juvenile sockeye salmon have a thermal
refuge from bass predation (Fayram and Sibley, 2000). In addition, in their study of
predation by smallmouth bass on riverine hatchery and wild salmonids in Washington,
Fritts and Pearsons (2004) found that smallmouth bass also seem to switch in June from a
diet composed of fish, to a diet composed of a higher percentage of invertebrates and
crayfish.
In fact, rather than having a negative impact on salmonids, observations on Vancouver Island suggest that bass predation on sunfish may have resulted in increased numbers of trout (Table 9) (Cassin and Silvestri, 2002(a); Cassin and Silvestri, 2002(c). Studies by the Oregon Department of Fish and Wildlife similarly found that direct impacts of bass on trout were reduced or eliminated by thermal segregation of bass and trout habitat, and the presence of bass may even have benefits offsetting any suspected negative impacts on salmonids. In this case, avian predation, which is a significant mortality factor for trout, was thought to be reduced because of buffering by bass which are behaviourally more vulnerable to avian predators (Shrader, 1993).