At least 14 species of Dactylogyrus are found in Lake Huron, 5 in Lake Superior and 6 in Lake Erie. To date, Dactylogyrus hemiamphibothrium has been found only in Eurasian Ruffe in Lake Superior. Extreme care should be taken with species identification as members of this genus are quite similar.

Summary of species impacts derived from literature review. Click on an icon to find out more...

Environmental

There is little or no evidence to support that Dactylogyrus hemiamphibothrium has significant environmental impacts in the Great Lakes.
Potential:
Dactylogyrus hemiamphibothrium is a parasite of percids, particularly in the genus Gymnocephalus (U.S. Department of the Interior 1993); it has also been reported to parasitize the genus Perca (Gibson et al. 1996). Due to host specificity for Eurasian ruffe (G. cernua) in its native range, D. hemiamphibothrium is unlikely to exert negative impacts on native fish species in the Great Lakes (U.S. Department of the Interior 1993).

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

There is little or no evidence to support that Dactylogyrus hemiamphibothrium has significant beneficial effects in the Great Lakes.
Potential:
In the Great Lakes, D. hemiamphibothrium appears to be host specific to the introduced Eurasian Ruffe (Gymnocephalus cernua) (U.S. Department of the Interior 1993), infection of which could lead to population reductions. However, no such effects have yet been realized in the Great Lakes.

Regulations (pertaining to the Great Lakes)
There are no known regulations for this species.

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

Control
Biological
Implementation of Eurasian Ruffe management may potentially decrease D. hemiamphibothrium prevalence due to host specificity. However, Ruffe management is considered by some (e.g., Ogle 1998) to be difficult and impractical given that the species has developed several adaptations to compensate for high mortality rates (Lind 1977) and populations rebound quickly (Lelek 1987).

Physical
Establishment of quarantines may prevent monogenean fluke transmission (Reed et al. 1996).

Chemical
Dactylogyrus hemiamphibothrium specific treatments are unknown. However, multiple chemicals are effective at treating monogenean fluke infections in aquaculture systems. Effective benzimidazoles include levamisole (Buchmann 1997) and praziquantel, which has high efficacy against Dactylogyrus ssp. (Buchmann 1997, Schmahl and Mehlhorn 1985). Effective bath treatments include formaldehyde (30-100 ppm), sodium chloride, copper sulphate, hydrogen peroxide, sodium percarbonate (Buchmann and Kristensen 2003), formalin (25 mg/L for prolonged exposure or 150-250 mg/L for 30 minutes), and potassium permanganate (2 mg/L for prolonged exposure or 10 mg/L for 30 minutes) (Reed et al. 1996). Effective organophsophate bath treatments include metrifonate (0.25-0.5 ppm) and dichlorvos (0.25-0.5 ppm) (Sarig et al. 1965).
Pond infestations can be controlled with formalin (30 mg/L) or trichlorfon (Lepidex®; 0.5 mg/L) (Reed et al. 1996). However, monogenean eggs display chemical resilience and therefore the above chemical treatments are ineffective at destroying eggs (Reed et al. 1996, Rowland et al. 2007). Chemical toxicity varies considerably between monogeneans and fish species. Toxicology and tolerance tests are suggested prior to using anthelmintics (“dewormers”). Managers are encouraged to consider specific host drug tolerance, temperature, salinity, organic material content, and drug retention time prior to treatment (Buchmann and Bresciani 2006). Freshwater fish species can also be dipped in saltwater to minimize external parasite numbers prior to stocking (Reed et al. 1996).

Other
Lampricide TFM may effectively eliminate up to 97% of ruffe, potential carriers of D. hemiamphibothrium, with minimal non-target mortality (Crosier et al. 2012).

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