Potential Effects of Bigheaded Carps on Four Laurentian Great Lakes Food Webs

Abstract

Bigheaded carps (BHCs; Silver Carp Hypophthalmichthys molitrix and Bighead Carp H. nobilis) are economically and culturally important in Asia and Europe but are considered highly invasive throughout the Mississippi River watershed and pose a threat to the food web and fisheries of the Laurentian Great Lakes. We used the Ecopath with Ecosim model framework to evaluate potential risk of BHC population growth and food web effects in four Great Lakes habitats, including mesotrophic waters of Saginaw Bay (Lake Huron) and Lake Erie and the oligotrophic main basins of Lakes Michigan and Huron. We simulated BHC population growth and food web effects under different scenarios of BHC production rates, prey vulnerability to BHCs, and availability of age‐0 BHCs to predation by salmonines. In the main basins of Lakes Michigan and Huron, the projected BHC population growth was low or negative, with a projected final BHC biomass of 0.5–1.1 times the initial introductory biomass (2% of total fish biomass for each BHC species), and BHCs had negligible effects on most food web groups across all scenarios. In contrast, in Saginaw Bay and Lake Erie, the projected BHC biomass was 2.5–12.5 times higher than the initial biomass across all scenarios, and the largest increases occurred under scenarios of high prey vulnerability to BHCs and high BHC production rates. High projected BHC biomass in Saginaw Bay and Lake Erie had negative effects on zooplankton and planktivorous fish groups and mixed effects on piscivores but had relatively negligible effects on most other food web groups across all scenarios. Our results are consistent with reported BHC effects on food webs in the Mississippi River and its tributaries and inform efforts to prevent BHC invasion of the Great Lakes.

Influence of invasive bigheaded carps on abundance of Gizzard Shad in the Tennessee River

“…Competition could also be detrimental to inland commercial and recreational fisheries that support important aspects of the regional economy. If bigheaded carps become established in the main-stem reservoirs of the Tennessee River, they could cause detrimental and extensive degradation in the fisheries (Chick and Pegg 2001;Cooke and Hill 2010;Tsehaye et al 2013;Sass et al 2014;Rutherford et al 2021).…”

Space and Species Interactions in Welfare Estimates for Invasive Species Policy

“…Silver Carp, Hypophthalmichthys molitrix, and Bighead Carp, Hypophthalmichthys nobilis, (collectively and henceforth bigheaded 1 carp) are AIS that have been traveling up the Mississippi River and are expected to enter the southern basin of Lake Michigan and spread throughout the lake. Currently, the invasion front is just 76 km away from Lake Michigan (Rutherford et al, 2021). The invasive bigheaded carp are strong competitors that may outcompete larval fish for algae and zooplankton (Solomon et al, 2016;Pendleton et al, 2017;Phelps et al, 2017;DeBoer et al, 2018) or may outcompete forage fish (e.g., alewife, Alosa pseudoharengus or rainbow smelt, Osmerus mordax) -which are primary food for the salmonines (e.g., Chinook salmon, Oncorhynchus tshawytscha, Coho salmon, Oncorhynchus kisutch, lake trout Salvelinus namaycush, or steelhead (rainbow trout), Oncorhynchus mykiss) that are economically important to the recreational sportfishing industry.…”

“…These interactions and any resultant damages will depend on the specific ecological characteristics of different spatial locations in Lake Michigan (Cooke and Hill, 2010;Rutherford et al, 2021). Some studies indicate that bigheaded carp could establish in Lake Michigan (Rutherford et al, 2021) in the nearshore areas and embayment (fish nursery waters) because there are more nutrient resources, and in suitable habitat in the deep chlorophyll layer offshore (Alsip et al, 2019(Alsip et al, , 2020. Other studies, however, have shown that the productivity in Lake Michigan is too low for bigheaded carp to survive (Cooke et al, 2009;Cooke and Hill, 2010;Rutherford et al, 2021).…”

“…Some studies indicate that bigheaded carp could establish in Lake Michigan (Rutherford et al, 2021) in the nearshore areas and embayment (fish nursery waters) because there are more nutrient resources, and in suitable habitat in the deep chlorophyll layer offshore (Alsip et al, 2019(Alsip et al, , 2020. Other studies, however, have shown that the productivity in Lake Michigan is too low for bigheaded carp to survive (Cooke et al, 2009;Cooke and Hill, 2010;Rutherford et al, 2021). While it is not clear if bigheaded carp will have the feared detrimental impacts on the recreational fishery and an already fragile lake ecosystem (e.g., Madenjian et al, 2015;Kao et al, 2018;Alsip et al, 2019Alsip et al, , 2020Rutherford et al, 2021), many organizations are actively engaging in research, monitoring, and control including, for example, the U.S. Army Corps of Engineers, the Department of the Interior's USGS, the Illinois Department of Natural Resources, and the U.S.…”

“…Other studies, however, have shown that the productivity in Lake Michigan is too low for bigheaded carp to survive (Cooke et al, 2009;Cooke and Hill, 2010;Rutherford et al, 2021). While it is not clear if bigheaded carp will have the feared detrimental impacts on the recreational fishery and an already fragile lake ecosystem (e.g., Madenjian et al, 2015;Kao et al, 2018;Alsip et al, 2019Alsip et al, , 2020Rutherford et al, 2021), many organizations are actively engaging in research, monitoring, and control including, for example, the U.S. Army Corps of Engineers, the Department of the Interior's USGS, the Illinois Department of Natural Resources, and the U.S. Fish and Wildlife Service.…”