Few studies exist on this species' effects on predator-prey relationships, competition, effects on water quality, or other environmental factors

There is little or no evidence to support that Enneacanthus gloriosus has significant socio-economic impacts in the Great Lakes.

No negative impacts to human health or economics have been reported.

Current research on the beneficial effect of Enneacanthus gloriosus in the Great Lakes is inadequate to support proper assessment.

Few studies exist on any beneficial impact this species may have in the Great Lakes region.

Note: Check federal, state/provincial, and local regulations for the most up-to-date information.

Control
Biological
There are no known biological control methods specific to this species.  Manipulation of the trophic cascade (stocking of predators such as pike, bass or walleye) may provide some measure of control.

Physical
There are no known physical control methods for this species.

Chemical
Of the four chemical piscicides  registered for use in the United States, antimycin A and rotenone are considered “general” piscicides, but no studies have been found of their effects on Enneacanthus gloriosus (GLMRIS 2012).

Increasing CO2 concentrations, either by bubbling pressurized gas directly into water or by the addition of sodium bicarbonate (NaHCO3) has been used to sedate fishes with minimal residual toxicity, and is a potential method of harvesting fish for removal, though maintaining adequate CO2 concentrations may be difficult in large/natural water bodies (Clearwater et al. 2008). CO2 is approved only for use as an anesthetic for cold, cool, and warm water fishes the US, not for use as euthanasia, and exposure to NaHCO3 concentration of 142-642 mg/L for 5 min. is sufficient to anaesthetize most fish (Clearwater et al. 2008).

Gonzalez and Dunson (1989) found that Enneacanthus gloriosus exposed to pH 4.25 and 4.0 grew at a lower rate (30-40% less growth) than fish of the same species exposed to higher pH (4.5, 5.0, 5.8). Survival of E. gloriosus was reduced at pH 3.5 and eliminated at pH 3.25, and the authors concluded that E. gloriosus would be excluded from habitats that regularly drop below pH 4.0 (Gonzalez and Dunson 1989).

It should be noted that chemical treatment will often lead to non-target kills, and so all options for management of a species should be adequately studied before a decision is made to use piscicides or other chemicals. Potential effects on non-target plants and organisms, including macroinvertebrates and other fish, should always be deliberately evaluated and analyzed. The effects of combinations of management chemicals and other toxicants, whether intentional or unintentional, should be understood prior to chemical treatment. Boogaard et al. (2003) found that the lampricides 3-trifluoromethyl-4-nitrophenol (TFM) and 2’,5-dichloro-4’-nitrosalicylanilide (niclosamide) demonstrate additive toxicity when combined. In another study on cumulative toxicity, combinations of Bayer 73 (niclosamide) and TFM with contaminants common in the Great Lakes (pesticides, heavy metals, industrial organics, phosphorus, and sediments) were found to be mostly additive in toxicity to rainbow trout, and one combination of TFM, Delnav, and malathion was synergistic, with toxicity magnified 7.9 times (Marking and Bills 1985). This highlights the need for managers to conduct on-site toxicity testing and to give serious consideration to determining the total toxic burden to which organisms may be exposed when using chemical treatments (Marking and Bills 1985). Other non-selective alterations of water quality, such as reducing dissolved oxygen levels or altering pH, could also have a deleterious impact on native fish, invertebrates, and other fauna or flora, and their potential harmful effects should therefore be evaluated thoroughly.

Note: Check state/provincial and local regulations for the most up-to-date information regarding permits for control methods. Follow all label instructions.