scholarly journals Mercury source changes and food web shifts alter contamination signatures of predatory fish from Lake Michigan

2019 ◽  
Vol 116 (47) ◽  
pp. 23600-23608 ◽  
Author(s):  
Ryan F. Lepak ◽  
Joel C. Hoffman ◽  
Sarah E. Janssen ◽  
David P. Krabbenhoft ◽  
Jacob M. Ogorek ◽  
...  
Keyword(s):  
Invasive Species ◽  
Great Lakes ◽  
Food Web ◽  
Lake Michigan ◽  
Lake Trout ◽  
Mitigation Strategies ◽  
Predatory Fish ◽  
Isotopic Analyses ◽  
C And N ◽  
The Impact

To understand the impact reduced mercury (Hg) loading and invasive species have had on methylmercury bioaccumulation in predator fish of Lake Michigan, we reconstructed bioaccumulation trends from a fish archive (1978 to 2012). By measuring fish Hg stable isotope ratios, we related temporal changes in Hg concentrations to varying Hg sources. Additionally, dietary tracers were necessary to identify food web influences. Through combined Hg, C, and N stable isotopic analyses, we were able to differentiate between a shift in Hg sources to fish and periods when energetic transitions (from dreissenid mussels) led to the assimilation of contrasting Hg pools (2000 to present). In the late 1980s, lake trout δ202Hg increased (0.4‰) from regulatory reductions in regional Hg emissions. After 2000, C and N isotopes ratios revealed altered food web pathways, resulting in a benthic energetic shift and changes to Hg bioaccumulation. Continued increases in δ202Hg indicate fish are responding to several United States mercury emission mitigation strategies that were initiated circa 1990 and continued through the 2011 promulgation of the Mercury and Air Toxics Standards rule. Unlike archives of sediments, this fish archive tracks Hg sources susceptible to bioaccumulation in Great Lakes fisheries. Analysis reveals that trends in fish Hg concentrations can be substantially affected by shifts in trophic structure and dietary preferences initiated by invasive species in the Great Lakes. This does not diminish the benefits of declining emissions over this period, as fish Hg concentrations would have been higher without these actions.

7. Examining the Impacts of Zebra Mussels as an Invasive Species in the Great Lakes Region and the Role of Stakeholders in Effective Mitigation Strategies

2018 ◽  
Author(s):  
Shuang Liang
Keyword(s):  
Great Lakes ◽  
Native Species ◽  
Public Awareness ◽  
Management Strategies ◽  
Zebra Mussels ◽  
Mitigation Strategies ◽  
Trophic Levels ◽  
Light Transmittance ◽  
Great Lakes Region ◽  
The Impact

Zebra mussels were first introduced into the Great Lakes region in 1988, via the ballast water of international ships traveling through the St. Lawrence River. Since then, the aggressive colonization of zebra mussels have had devastating effects on the native aquatic biodiversity in the Great Lakes region. The continued proliferation of zebra mussels have led to increased filtering, high light transmittance through water and growth of benthic (lowest level of a body of water) plants. Due to the intensive filtration of zebra mussels, rapid bioaccumulation of botulinum toxin in their systems have caused high levels of mortality for waterfowl predators. As zebra mussels continue to dominate in predator-prey interactions and interspecies competition, a shift in the ecosystem equilibrium is occurring on varying trophic levels. These changes have not gone unnoticed. Zebra mussels have cost Canadian industries, businesses and communities over $5 billion in a single decade in clogged pipes and turbine damages. The associated economic repercussions from infrastructural damages and native species declines necessitate engagement from a multitude of stakeholders. Public awareness is absolutely vital in minimizing the impact of zebra mussels and preventing their distribution across freshwater in North America. In this presentation, I will discuss the ecological, economic and societal impacts of zebra mussels since their introduction to the Great Lakes region. In addition, I will examine a multitude of management strategies and recommendations to government, private sector and public stakeholders to reduce future impacts of mussels in the Great Lakes region.

21. Invasion of Asian Carp in the Great Lakes

2018 ◽  
Author(s):  
Kassandra Smrekar ◽  
Shingo Tanaka ◽  
Lavie Williams
Keyword(s):  
Invasive Species ◽  
Great Lakes ◽  
Mississippi River ◽  
North American ◽  
Native Species ◽  
Lake Michigan ◽  
Fundamental Problem ◽  
Public Awareness ◽  
Asian Carp ◽  
Freshwater Species

A recent threat posed to the Great Lakes and adjoining waterways is the Asian Carp.  This large bodied fish originated from Asia and was first imported to the North American between 1960 to 1970. Their migration northward through the Mississippi River eliminated native freshwater species through competition of habitat and food resources. It is imperative to focus on the potential invasion of the Asian Carp because the risk assessment is high that the carp would eliminate all native species.  Currently the carp are at the border of entering Lake Michigan, which would then provide access to the rest of the freshwater regions in the surrounding area. Ultimately, the loss of lake biodiversity is the fundamental problem and is coupled with economic issues.  Bowfin Environmental Consulting INC and various invasive species awareness programs have been utilized to provide guidance on undertaking a project that involves an aggressive invasive species.  The challenge faced will be to determine a method in which to prevent the invasion of Asian Carp.  Examining their migration patterns, importation laws of live fish, and the policies of invasive species, will provide insight on the approach that should be taken to eliminate the threat of Asian Carp.  It is also important to analyze which native species are most susceptible to becoming extinct.  Overall, the intention is not only to increase government, scientific, and public awareness of this issue, but also to provide methods that can be implemented to prevent and eradicate the spread of Asian Carp in North American waterways.

Prey fish exploitation, salmonine production, and pelagic food web efficiency in Lake Ontario

1998 ◽  
Vol 55 (2) ◽  
pp. 318-327 ◽  
Author(s):  
Peter S Rand ◽  
Donald J Stewart
Keyword(s):  
Food Web ◽  
Lake Michigan ◽  
Oncorhynchus Tshawytscha ◽  
Lake Trout ◽  
Coho Salmon ◽  
Lake Ontario ◽  
Osmerus Mordax ◽  
Prey Fish ◽  
Rainbow Smelt ◽  
Time Model

Estimates of production and predation rates from bioenergetic models of chinook salmon (Oncorhynchus tshawytscha), coho salmon (Oncorhynchus kisutch), and lake trout (Salvelinus namaycush) suggest a long-term decline in their gross conversion efficiency (gross production/prey consumption) and the gross production to biomass ratio in Lake Ontario during 1978-1994. The former pattern was caused primarily by a declining trend in adult alewife (Alosa pseudoharengus) energy density during 1978-1985; the latter pattern resulted from reductions in growth rates (coho salmon) and a buildup of the older age-classes in the population (lake trout) over time. Model results suggest that over 100 and 25% of the annual production of adult alewife and rainbow smelt (Osmerus mordax), respectively, was consumed by salmonines during 1990 in Lake Ontario; hence, we claim that recent observations of reduced salmonine growth in Lake Ontario may be a result of prey limitation. Energy transfer from primary production to salmonines appeared to be more efficient in Lake Ontario than in Lake Michigan, probably due to higher stocking levels per unit area and higher densities of preferred prey fish in Lake Ontario. Through separate analyses, we arrived at conflicting conclusions concerning the sustainability of the food web configuration in Lake Ontario during 1990.

Rehabilitation of Lake Ontario: the Role of Nutrient Reduction and Food Web Dynamics

1991 ◽  
Vol 48 (8) ◽  
pp. 1574-1580 ◽  
Author(s):  
John H. Hartig ◽  
James F. Kitchell ◽  
Donald Scavia ◽  
Stephen B. Brandt
Keyword(s):  
Water Quality ◽  
Great Lakes ◽  
Food Web ◽  
Toxic Substance ◽  
Lake Ontario ◽  
The United States ◽  
Food Web Dynamics ◽  
Food Web Interactions ◽  
The Impact

The Laurentian Great Lakes have a complex history of changes due to eutrophication, invasion of exotic species, and fisheries and phosphorus management practices. Remedial actions have reduced nutrient loadings and enhanced the role of food web interactions in improving water quality. Workshops sponsored through the United States – Canada international Joint Commission have addressed the relative importance of nutrient abatement and/or food web manipulation in affecting water quality trends. Both controls have combined to enhance water clarity in Lake Michigan. Lake Ontario has already exhibited the effects of nutrient controls and may be on the verge of manifesting food web controls. Research and monitoring recommendations to elucidate the effects of nutrient and food web controls include the following: (1) water quality and fisheries agencies must coordinate monitoring activities, standardize techniques, and establish and maintain long-term data sets to evaluate the effects of water quality and fisheries programs separately and together; (2) controlled, mesoscale, whole-system experiments should be performed to quantify rates (e.g. growth, predation, etc.) of food web interactions; and (3) the scientific community should promote research which quantifies the impact of changes in food web dynamics on changes in toxic substance levels in Great Lakes fishes.

Spatial variability of lake trout diets in Lakes Huron and Michigan revealed by stomach content and fatty acid profiles

2018 ◽  
Vol 75 (1) ◽  
pp. 95-105 ◽  
Author(s):  
Austin Happel ◽  
Jory L. Jonas ◽  
Paul R. McKenna ◽  
Jacques Rinchard ◽  
Ji Xiang He ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Great Lakes ◽  
Lake Michigan ◽  
Lake Trout ◽  
Stomach Contents ◽  
Neogobius Melanostomus ◽  
Lake Huron ◽  
Fatty Acid Profiles ◽  
Rainbow Smelt ◽  
Western Lake

Despite long-term efforts to restore lake trout (Salvelinus namaycush) populations in the Great Lakes, they continue to experience insufficient recruitment and rely on hatchery programs to sustain stocks. As lake trout reproductive success has been linked to diets, spatial heterogeneity in diet compositions is of interest. To assess spatial components of adult lake trout diets, we analyzed stomach contents and fatty acid profiles of dorsal muscle collected throughout Lake Michigan and along Lake Huron’s Michigan shoreline. Lake trout from Lake Huron were generally larger in both length and mass than those from Lake Michigan. However, lake trout from Lake Michigan varied more in size based on depth of capture with smaller fish being caught more in deeper set nets. Fatty acids and stomach contents indicated that alewife (Alosa pseudoharengus) were consumed more in western Lake Michigan in contrast with round goby (Neogobius melanostomus) along the eastern shoreline. Conversely, in Lake Huron, lake trout primarily consumed rainbow smelt (Osmerus mordax). These results indicate that diet compositions of lake trout populations are relatively plastic and offer new insights into within-basin heterogeneity of Great Lakes food webs.

scholarly journals A novel approach to quantifying trophic interaction strengths and impact of invasive species in food webs

2021 ◽  
Author(s):  
Edoardo Calizza ◽  
Loreto Rossi ◽  
Giulio Careddu ◽  
Simona Sporta Caputi ◽  
Maria Letizia Costantini
Keyword(s):  
Invasive Species ◽  
Food Web ◽  
Food Webs ◽  
Fish Species ◽  
Trophic Interaction ◽  
Coregonus Lavaretus ◽  
Commercial Fish ◽  
Novel Approach ◽  
Allochthonous Species ◽  
The Impact

AbstractMeasuring ecological and economic impacts of invasive species is necessary for managing invaded food webs. Based on abundance, biomass and diet data of autochthonous and allochthonous fish species, we proposed a novel approach to quantifying trophic interaction strengths in terms of number of individuals and biomass that each species subtract to the others in the food web. This allowed to estimate the economic loss associated to the impact of an invasive species on commercial fish stocks, as well as the resilience of invaded food webs to further perturbations. As case study, we measured the impact of the invasive bass Micropterus salmoides in two lake communities differing in food web complexity and species richness, as well as the biotic resistance of autochthonous and allochthonous fish species against the invader. Resistance to the invader was higher, while its ecological and economic impact was lower, in the more complex and species-rich food web. The percid Perca fluviatilis and the whitefish Coregonus lavaretus were the two species that most limited the invader, representing meaningful targets for conservation biological control strategies. In both food webs, the limiting effect of allochthonous species against M. salmoides was higher than the effect of autochthonous ones. Simulations predicted that the eradication of the invader would increase food web resilience, while that an increase in fish diversity would preserve resilience also at high abundances of M. salmoides. Our results support the conservation of biodiverse food webs as a way to mitigate the impact of bass invasion in lake ecosystems. Notably, the proposed approach could be applied to any habitat and animal species whenever biomass and diet data can be obtained.

Sign in / Sign up

Export Citation Format

Share Document