Northern Madtom Use of Artificial Reefs in the St. Clair–Detroit River System

Abstract

The St. Clair and Detroit rivers historically supported abundant fish populations. However, like many river systems, these rivers have been greatly altered through the creation of navigation channels and other anthropogenic disturbances, resulting in the loss of fish and wildlife habitat and declines in native fish populations. To ameliorate this environmental degradation, artificial fish spawning reefs were constructed in the St. Clair and Detroit rivers. One native species to potentially benefit from artificial reefs is the Northern Madtom Noturus stigmosus, a small ictalurid that is listed as endangered in the state of Michigan and the province of Ontario. Between 2016 and 2018, artificial reefs and nearby control sites were sampled in the St. Clair and Detroit rivers to compare the number of Northern Madtoms. In total, 171 Northern Madtoms were captured in 1,848 minnow traps with one of four bait types: cheese, dog food, worms, or control (no bait). Baited minnow traps successfully captured Northern Madtoms in the fast‐flowing, deep water of the St. Clair–Detroit River system, and catch rates were significantly higher when traps were baited with worms. The number of Northern Madtoms captured was lower in the Detroit River than in the St. Clair River and increased with increasing water temperature and turbidity. Artificial reefs constructed in the St. Clair–Detroit River system are providing habitat for Northern Madtoms; however, use did not differ between reef sites and nearby control sites. This work provides insight regarding sampling strategies to target Northern Madtoms in large‐river systems and highlights the importance of incorporating a temporal sampling strategy into survey design.

Biological Investigation of the Endangered Northern Madtom in the North Channel St. Clair River

“…Substantial recent work in the system has sought to increase the number of spawning reefs available for Lake Sturgeon and other species (e.g., Manny et al 2015;Hartig et al 2018;Fischer et al 2020). However, Johnson et al (2021) did not find a strong association between Northern Madtom and newly constructed reef INVESTIGATION OF ENDANGERED NORTHERN MADTOM habitat. Lamothe et al (2020) reported a negative relationship between Round Goby Neogobius melanostomus and Northern Madtom abundance in trawl data of the St. Clair River.…”

“…However, Johnson et al. (2021) did not find a strong association between Northern Madtom and newly constructed reef habitat. Lamothe et al.…”

“…An additional 34 samples collected in the Detroit River by the U.S. Fish and Wildlife Service were also processed for comparison (see Johnson et al 2021). The DNA was extracted following manufacturer's protocols for the Qiagen DNeasy Blood and Tissue kit (Qiagen, Germantown, Maryland).…”

“…In Michigan, isolated populations are currently found in the St. Clair, Detroit, and Huron rivers (Bailey et al 2004). Recent work has investigated habitat use of Northern Madtom (e.g., Johnson et al 2021) and interactions with invasive species (Lamothe et al 2020); however, information regarding Northern Madtom growth, diet, fecundity, mortality, and genetic relationships among populations are mostly unknown due to the species' cryptic nature, low abundance, and naturally patchy distribution (e.g., Scheibly et al 2008;Manny et al 2014). Such biological data are needed to inform basic decisions regarding Northern Madtom management in the St. Clair-Detroit River system and provide reference points of population status and life history parameters to aid managers with the assessment of recovery efforts, including habitat restoration, and evaluation of listing status in the St. Clair-Detroit River system and elsewhere.…”

“…Recent work has investigated habitat use of Northern Madtom (e.g., Johnson et al. 2021) and interactions with invasive species (Lamothe et al. 2020); however, information regarding Northern Madtom growth, diet, fecundity, mortality, and genetic relationships among populations are mostly unknown due to the species' cryptic nature, low abundance, and naturally patchy distribution (e.g., Scheibly et al.…”