Terms of Reference

Habitat-Based Carrying Capacity Estimates for Alewife (Alosa pseudoharengus) in the Skutik (St. Croix) River Watershed

Regional Peer Review - Gulf Region

November 25-26, 2024

Virtual

Chairperson: Darek Moreau

Context

In the Skutik (St. Croix) River watershed, New Brunswick, movement of diadromous fishes has been limited by dam infrastructure for over a century. With the removal of the Milltown Dam in 2024 there has been renewed interest in restoring diadromous fish populations. The species of interest are mainly alewife (Alosa pseudoharengus) and blueback herring (Alosa aestivalis), collectively known as gaspereau or river herring. The Fish and Fish Habitat Protection Program (FFHPP) has asked Science for estimates of the potential productivity of alewife in this system to help inform restoration goals.

Previous models and meta-analyses have been developed by Fisheries and Oceans Canada (DFO) Science and other sources (Barber 2018, Barber et al. 2018, Dill et al. 2010, Gibson and Myers 2003) to estimate alewife populations for similar systems. These models can be used to develop watershed-specific science advice in support of a range of management objectives. Here, the results of the meta-analysis of alewife populations will be applied to estimate carrying capacity of the Skutik River watershed alewife population based on estimates of available nursery area (Gibson and Myers 2003, Gibson et al. 2017). This approach has been used for alewife populations in the Tusket River (Bowlby and Gibson 2016), Sandy Lake, Halifax County (DFO 2016) and in the Saint John River upstream of Mactaquac dam (DFO 2024).

The aim of this Science Advisory Process is to estimate alewife nursery area, and provide a median estimate and range of alewife carrying capacity in the Skutik River watershed. The carrying capacity estimates will be based on the nursery area that is accessible, potentially accessible, and artificially inaccessible, excluding only naturally inaccessible areas.

Objectives

This process will provide scientific advice using habitat carrying capacity estimates (Gibson and Myers 2003) with respect to the following objectives:

1. Estimate the potential nursery area available to alewife in the Skutik River watershed.
2. Estimate the median and range of carrying capacity for alewife that the Skutik River watershed could theoretically support.

Expected Publications

• Science Advisory Report
• Research Document

Expected Participation

• Fisheries and Oceans Canada (DFO) (Science and Fish and Fish Habitat Protection Program)
• Indigenous communities/organizations
• Provincial governments
• Academia
• External experts

References

• Barber, B. 2018. Marine-Derived Nutrient Cycling in the St. Croix River, Maine. Thesis (PhD.) University of Maine. 236 p.
• Barber et al 2018. Does What Goes up Also Come Down? Using a Recruitment Model to Balance Alewife Nutrient Import and Export. Marine and Coastal Fisheries. 10:236–254. DOI: 10.1002/mcf2.10021
• Bowlby, H.D., and Gibson, A.J.F. 2016. River Herring Assessment for the Tusket River, Nova Scotia. DFO Can. Sci. Advis. Sec. Res. Doc. 2016/106. v + 45 p.
• DFO. 2016. Habitat, Passage and Stocking Considerations for Gaspereau at Sandy Lake, Nova Scotia. DFO Can. Sci. Advis. Sec. Sci. Resp. 2016/005.
• DFO. 2024. Habitat-Based Reference Points for Saint John River Alewife, Upstream Of Mactaquac Dam. DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2024/051.
• Dill, R., Trial, J., Atkinson, E., Gibson, J., Jordan, R., Lary, S., Saunders, R. and Seymour, P. 2010. An Adaptive Plan for Managing Alewife in the St. Croix River Watershed, Maine and New Brunswick. International St. Croix River Watershed Board, International Joint Commission. Proposal for Discussion. 24 p.
• Gibson, A.J.F., Bowlby, H.D., and Keyser, F.M. 2017. A Framework for the Assessment of the Status of River Herring Populations and Fisheries in DFO’s Maritimes Region. DFO Can. Sci. Advis. Sec. Res. Doc. 2016/105. vi + 69 p.
• Gibson, A. J. F., & Myers, R. A. (2003). A meta-analysis of the habitat carrying capacity and maximum reproductive rate of anadromous alewife in eastern North America. American Fisheries Society Symposium. 35: 211-221.