A scientific basis for restoring fish spawning habitat in the St. Clair and Detroit Rivers of the Laurentian Great Lakes

Abstract

Loss of functional habitat in riverine systems is a global fisheries issue. Few studies, however, describe the decision‐making approach taken to abate loss of fish spawning habitat. Numerous habitat restoration efforts are underway and documentation of successful restoration techniques for spawning habitat of desirable fish species in large rivers connecting the Laurentian Great Lakes are reported here. In 2003, to compensate for the loss of fish spawning habitat in the St. Clair and Detroit Rivers that connect the Great Lakes Huron and Erie, an international partnership of state, federal, and academic scientists began restoring fish spawning habitat in both of these rivers. Using an adaptive management approach, we created 1,100 m2 of productive fish spawning habitat near Belle Isle in the Detroit River in 2004; 3,300 m2 of fish spawning habitat near Fighting Island in the Detroit River in 2008; and 4,000 m2 of fish spawning habitat in the Middle Channel of the St. Clair River in 2012. Here, we describe the adaptive‐feedback management approach that we used to guide our decision making during all phases of spawning habitat restoration, including problem identification, team building, hypothesis development, strategy development, prioritization of physical and biological imperatives, project implementation, habitat construction, monitoring of fish use of the constructed spawning habitats, and communication of research results. Numerous scientific and economic lessons learned from 10 years of planning, building, and assessing fish use of these three fish spawning habitat restoration projects are summarized in this article.

Lake Sturgeon, Lake Whitefish, and Walleye Egg Deposition Patterns with Response to Fish Spawning Substrate Restoration in the St. Clair–Detroit River System

“…To assess the effectiveness of restoration sites where 10–20‐cm rock had been placed to provide spawning substrate for lithophilic species (Manny et al. ), sites over artificial spawning reefs (Figure ) were classified “reef” sites, and all other sites were considered “non‐reef” sites. The Middle Channel reefs were buried by sand substrates in 2013 (Manny et al.…”

“…The Middle Channel reefs were buried by sand substrates in 2013 (Manny et al. ), so they were classified as non‐reef sites from 2014 to 2016. Lastly, “river” was included as a variable to account for differences between the St. Clair and Detroit rivers.…”

“…; Manny et al. ). Regulations limiting the harvest of these fish species have since been instated to reduce adult mortality, but habitat loss can continue to limit the recovery of overfished species (e.g., Pollock et al.…”

“…In an effort to address losses of spawning substrates from the SCDRS, habitat restoration has been underway since 2004 to create spawning areas for lithophilic‐spawning fishes by constructing rock reefs near historical spawning areas (Manny et al. ; Vaccaro et al. ).…”

“…Projects prior to 2013 (Belle Isle, Fighting Island, and Middle Channel reefs) used 10–20‐cm angular broken limestone, rounded fieldstone, and coal cinders, but there was no statistical evidence that fishes spawned over one material more than another; therefore, current projects utilize broken limestone, the most cost‐effective option (Manny et al. ). Bennion and Manny () developed a spatial model based on water depths, velocities, and locations of historic spawning sites used by Lake Sturgeon in the SCDRS to inform the placement of artificial spawning reefs.…”