Consequences of changing water clarity on the fish and fisheries of the Laurentian Great Lakes

Abstract

Human-driven environmental change underlies recent changes in water clarity in many of the world’s great lakes, yet our understanding of the consequences of these changes on the fish and fisheries they support remains incomplete. Herein, we offer a framework to organize current knowledge, guide future research, and help fisheries managers understand how water clarity can affect their valued populations. Emphasizing Laurentian Great Lakes findings where possible, we describe how changing water clarity can directly affect fish populations and communities by altering exposure to ultraviolet radiation, foraging success, predation risk, reproductive behavior, or territoriality. We also discuss how changing water clarity can affect fisheries harvest and assessment through effects on fisher behavior and sampling efficiency (i.e., catchability). Finally, we discuss whether changing water clarity can affect understudied aspects of fishery performance, including economic and community benefits. We conclude by identifying generalized predictions and discuss their implications for priority research questions for the Laurentian Great Lakes. Even though the motivation for this work was regional, the breadth of the review and generality of the framework are readily transferable to other freshwater and marine habitats.

Depth and temperature drive patterns of spatial overlap among fish thermal guilds in lakes across Ontario, Canada

“…A small subset of lakes having highly turbid or coloured water (summer Secchi depth <1.76 m) showed high levels of spatial overlap between all guild pairs, with the highest value within that leaf seen for cool-and cold-water fishes. Previous studies have demonstrated that water clarity can hinder the foraging ability of visual predators (Bunnell et al, 2021;Estlander et al, 2010;McMahon & Holanov, 1995).…”

Associations between submerged macrophytes and fish communities at two spatial scales in 88 temperate shallow lakes

“…In addition, our results revealed that the negative relationships between macrophytes and total fish abundance as well as the abundance and biomass of fish <10 cm were strongly associated with lakes with high plant cover, as shown by the within-lakes approach. This pattern might not only reflect macrophyte cover per se, because lakes highly covered by submerged macrophytes have higher water clarity (Søndergaard et al, 2022), which may favour predation of fish (Bunnell et al, 2021). High predation rates by piscivorous fish in macrophyte patches may lead fish to avoid these places because of their inability to keep a sufficient distance from predators in limited space, thereby adopting an open-water antipredator strategy (Jacobsen & Perrow, 1998).…”

Ecosystem services provided by the exotic bivalves Dreissena polymorpha, D. rostriformis bugensis, and Limnoperna fortunei

“…Using the method and assumptions employed by Walsh et al ( 2016 ), we performed a rough estimate of the benefits conferred to properties around some of the Great Lakes by the increased water clarity from dreissenid filtration. In lakes Michigan and Huron, mussels increased Secchi depths from < 10 m in the 1980–1990s, to ~ 20 m in 2015–2019 (Barbiero et al, 2018 ; Bunnell et al, 2021 ; U.S. Environmental Protection Agency’ Great Lakes National Program Office 1983–2019 long-term monitoring water quality data, https://cdx.epa.gov/ ). A 9 m in Secchi depth increase and the same increase (i.e., willingness to pay) in neighboring property value per meter of extra water clarity as the one used by Walsh et al ( 2016 ) (in decreased value due to water turbidity) yields US$ 767.52 per house (adjusted to present values).…”

“…The extent of light penetration modifies the depth of the euphotic layer, and the ensuing growth of vegetation may affect fish habitats. Higher water clarity can also increase the penetration of ultraviolet radiation affecting the survival or distribution of some organisms, induce changes in fish schooling, reproductive behavior, territoriality (Bunnell et al, 2021 ), and even modify temperature and dissolved oxygen vertical stratification patterns (Yu & Culver, 2000 ). While nutrient sequestration from the water column by invasive bivalves, especially in lakes, has been well documented, studies of changes in their concentrations (in particular P and N) in the water yielded quite dissimilar results, with both increases and decreases having been reported, as well as differences in the changes of their various compounds (see “ Nutrient cycling and sequestration ” section; Lindim, 2015 ), suggesting that these impacts are context-dependent.…”