Terms of Reference

Science Response – Gulf Region

September 11, 2019
Moncton, NB

Chairperson: Matthew Hardy

Context

Smallmouth Bass (Micropterus dolomieu), a non-native species to New Brunswick was confirmed in 2008 to have been introduced and was now established in Miramichi Lake, a headwater lake of the Southwest Miramichi River, of the southern Gulf of St. Lawrence (DFO 2009). A risk assessment to Atlantic Salmon of the Miramichi River of this introduced and established non-native fish species concluded that there is a high likelihood of widespread establishment of Smallmouth Bass in the Southwest Miramichi River and in the Gulf Region rivers in general (DFO 2009). The overall risk to the aquatic ecosystem was considered to be high in the lake environment with Smallmouth Bass expected to become a dominant component of the food web and to cause significant reductions in existing biota; the uncertainty was considered low (DFO 2009). The overall risk was considered to be moderate in the riverine environment with a measurable decrease in abundance of native populations likely to occur in most locations due to the establishment of Smallmouth Bass; the uncertainty was concluded to be high (DFO 2009).

A range of containment/control/eradication options, including their effectiveness and impacts on the ecosystem components, were reviewed in the general context of non-native fish introductions and specifically for Miramichi Lake (Halfyard 2010). Eradication through chemical treatment was concluded to have the highest probability of complete removal in Miramichi Lake, however, even in closed systems, chemical treatment was not always 100% effective and it has the most negative consequences on the non-targeted native species (DFO 2009; Halfyard 2010). Physical barriers were considered to be the most effective immediate measure for containing the spread of smallmouth bass out of Miramichi Lake and this was actioned beginning in 2009 (Biron 2018). Control measures including intensive fishing in Miramichi Lake to remove adult and juvenile stages of Smallmouth Bass were undertaken, and although this reduced the abundance of Smallmouth Bass in the lake, it was not effective at eradicating Smallmouth Bass (Biron 2018).

In 2015, the Government of Canada revised the Fisheries Act and passed the Aquatic Invasive Species Regulations (SOR/2015-121) which gave authority to prescribed persons (Section 18) designated under paragraph 36(5)(f) of the Act to use piscicides to control invasive species; these designated persons included DFO and a number of provincial and territorial departments, but not the province of New Brunswick. The regulations also stipulate the species and the areas to which the regulations apply; Smallmouth Bass was identified in Schedule Part 3 as such a species in areas where it is not indigenous. Under these regulations, fish toxicants could be authorized in New Brunswick by the Minister of Fisheries and Oceans to control Smallmouth Bass as it is not an indigenous species to the Maritime provinces. The Aquatic Invasive Species Regulations also state that alternative measures and the impact on fish and fish habitat or use of fish must be taken into consideration before authorizing the deposit of a deleterious substance.

A non-government organization has submitted a request to the Minister of Fisheries and Oceans and the Canadian Coast Guard to authorise the deposit of a deleterious substance to control an aquatic invasive species pursuant to s. 19(3) of the Aquatic Invasive Species Regulations SOR / 2015-121 (AISR). The request is to deposit rotenone in Miramichi Lake for the purpose of eradicating Smallmouth Bass.

To support the decision making process, the Fisheries and Oceans Canada (DFO) Gulf Region Aquatic Invasive Species National Core Program asked DFO Science to review elements of the proponent's application.

Objectives

The review should advise on the adequacy of the information provided, the interpretation of the literature, and to identify gaps specific to the following considerations:

• Impact of Smallmouth Bass on species diversity and abundance of aquatic organisms Miramichi Lake and the Southwest Miramichi River, if no control efforts occur.
• Effectiveness of proposed eradication method including:
• Consideration of alternate methods for control and eradication.
• Feasibility of proposed project (i.e. risk of not achieving intended goal of eradication); including physical and anthropogenic concerns.
• Risk of re-introduction of the targeted species into the waterbody / watershed.
• Proposed monitoring protocol to quantify eradication effectiveness.
• Proposed contingency strategy if unsuccessful.
• In terms of defining impacts of the deposit:
• Resulting impact of loss of fish species in the lake in terms of ecosystem productivity;
• Impact to invertebrate communities that support the food web/productivity of the system; this is linked to the re-establishment strategy (i.e. foods resource for fish species); and
• Validity of proposed mitigation measures to "offset" the impacts described above (i.e. re-establishment strategy); in this case, the effectiveness of proposed re-establishment strategy.

The specific elements of the application to be reviewed are section 3 (all), section 4 (all), section 5.1, section 7 (all) and section 8 (monitoring).

Expected Publications

• CSAS Science Response Report

Participation

• Fisheries and Oceans Canada (DFO) (Ecosystems and Oceans Science, and Ecosystems and Fisheries Management)

References

DFO. 2009. Potential Impact of Smallmouth Bass Introductions on Atlantic Salmon: A Risk Assessment. DFO Can.Sci. Advis. Sec. Sci. Advis. Rep. 2009/003.
Biron, M. 2018. Review of the control and monitoring activities for Smallmouth Bass (Micropterus dolomieu) in Miramichi Lake, New Brunswick, in 2009 to 2017. Can. Manuscr. Rep. Fish. Aquat. Sci. No. 3166: ix + 38 p.
Halfyard, E.A. 2010. A review of options for the containment, control and eradication of illegally introduced smallmouth bass (Micropterus dolomieu). Can. Tech. Rep. Fish. Aquat. Sci. 2865: vi + 71 p.