Muskellunge Management: Fifty Years of Cooperation Among Anglers, Scientists, and Fisheries Biologists

2017 ◽  
Keyword(s):  
Size Structure ◽  
Population Decline ◽  
Round Goby ◽  
Management Plan ◽  
Neogobius Melanostomus ◽  
Before And After ◽  
Catch Rates ◽  
Survival Studies ◽  
St Lawrence River

<em>Abstract</em>.— Long-term research indicates a significant and ongoing decline within the upper St. Lawrence River Muskellunge <em>Esox masquinongy </em>population. Index surveys show a sharp reduction in catch of both spawning adults and age-0 Muskellunge, and catch rates by anglers have similarly declined while harvest remains low. Other changes associated with population decline include presence of fewer female adult Muskellunge and a change in adult Muskellunge size structure (increase in proportion of fish <1,016 mm) in addition to more large individuals greater than 1,372 mm. A significant adult die-off occurred from 2005 to 2008 (103 adults recovered in U.S. and Canadian waters) concomitant with an outbreak of viral hemorrhagic septicemia (VHS). These population changes were also temporally correlated with detection and proliferation of invasive Round Goby <em>Neogobius melanostomus</em>, a known VHS virus (VHSV) reservoir, egg predator, and competitor with native fishes. Comparisons of index netting before and after VHSV and Round Goby invasions suggest a direct link to the decline, but because these are correlations, we can only explore these effects. To examine the viability of Muskellunge nursery sites, we repeated survival studies conducted in the early 1990s with experimental releases of advanced fry at four locations during 2013–2015. Findings indicate contribution to age-0 populations, but catches poststocking (wild and stocked) were lower compared to the 1990s. We review information regarding potential stressors, including VHSV and Round Goby invasion, and conclude that their combined effects have created significant uncertainty and challenges to sustainable management of the Muskellunge population. In response, the St. Lawrence River Muskellunge management plan should be updated with a focus on restoration of the declining Muskellunge stock. Recommended actions target advancing conservation and restoration of critical habitat, restoring lost subpopulations, and reducing mortality associated with angling (e.g., from handling and harvest).

scholarly journals First Occurrence of the Round Goby, Neogobius melanostomus, in the St. Lawrence River at Cornwall, Ontario

2005 ◽  
Vol 119 (4) ◽  
pp. 582 ◽  
Author(s):  
M. Brian C. Hickey ◽  
Adrienne R. Fowlie
Keyword(s):  
Round Goby ◽  
Scuba Diving ◽  
Neogobius Melanostomus ◽  
Benthic Fish ◽  
First Occurrence ◽  
Round Gobies ◽  
St Lawrence River

We document the first reported occurrence of the Round Goby, Neogobius melanostomus, a small benthic fish native to the Black and Caspian seas, in the St. Lawrence River near Cornwall. On 7 September 2004, we observed approximately 20 Round Gobies while SCUBA diving at a depth of 7 m, downstream of the Saunders Generating Station at Cornwall, Ontario. Round Gobies appear to have arrived recently in this reach of the river and have not previously been detected despite extensive fish surveys conducted in the area.

Impacts of predation by the Eurasian round goby (Neogobius melanostomus) on molluscs in the upper St. Lawrence River

2012 ◽  
Vol 38 (1) ◽  
pp. 78-89 ◽  
Author(s):  
Rebekah Kipp ◽  
Issac Hébert ◽  
Myriam Lacharité ◽  
Anthony Ricciardi
Keyword(s):  
Round Goby ◽  
Neogobius Melanostomus ◽  
St Lawrence River

scholarly journals Ecological responses to elevated water temperatures across invasive populations of the round goby (Neogobius melanostomus) in the Great Lakes basin

2021 ◽  
Author(s):  
Heather Bauer Reid ◽  
Anthony Ricciardi
Keyword(s):  
Great Lakes ◽  
Climate Warming ◽  
Native Species ◽  
Elevated Temperatures ◽  
Round Goby ◽  
Neogobius Melanostomus ◽  
Acclimation Temperature ◽  
Feeding Rates ◽  
Western Basin ◽  
St Lawrence River

Climate warming is expected to alter the distribution, abundance, and impact of non-native species in aquatic ecosystems. In laboratory experiments, we measured the maximum feeding rate and critical thermal maximum (CTmax) of an invasive Eurasian fish, the round goby (Neogobius melanostomus), acclimated to a range of temperatures (18–28°C) reflecting current and projected future thermal conditions for the nearshore Great Lakes. Fish were collected from four distinct populations along a latitudinal gradient from the western basin of Lake Erie to Hamilton Harbour (Lake Ontario) and the upper St. Lawrence River. Thermal tolerance increased with acclimation temperature for populations in lakes Erie and Ontario. However, the St. Lawrence River populations had lower acclimation capacity and exhibited an unexpected decline in CTmax at the highest acclimation temperature. Maximum feeding rates peaked at 18–24°C and declined with temperatures above 24°C. Northern populations in the basin appear poorly adapted to elevated temperatures such that their performance and impact could be reduced by climate warming. Thermal response data from latitudinally distributed populations are needed to inform invasive species risk assessment.

Impacts of the Eurasian round goby (Neogobius melanostomus) on benthic communities in the upper St. Lawrence River

2012 ◽  
Vol 69 (3) ◽  
pp. 469-486 ◽  
Author(s):  
Rebekah Kipp ◽  
Anthony Ricciardi
Keyword(s):  
Great Lakes ◽  
Benthic Communities ◽  
Round Goby ◽  
River System ◽  
Benthic Algae ◽  
Large River ◽  
Neogobius Melanostomus ◽  
Benthivorous Fish ◽  
Ecosystem Impacts ◽  
St Lawrence River

An invasive benthivorous fish, the Eurasian round goby ( Neogobius melanostomus ) is abundant throughout the lower Great Lakes – St. Lawrence River system. We examined the round goby’s potential to alter benthic communities on cobble substrates in the upper St. Lawrence River. During the summers of 2008 and 2009, macroinvertebrates and benthic algae were sampled across sites with varying goby densities. Archived data from various sites in 2004–2006 (prior to invasion) were available for comparison. Macroinvertebrate community composition varied significantly among samples grouped into categories based on goby density and time since invasion. Macroinvertebrate diversity and dominance by large-bodied taxa declined with increasing goby density. Surprisingly, dreissenid biomass did not vary consistently with goby density, in contrast to studies in the Great Lakes. The biomass of all non-dreissenid taxa was negatively correlated with increasing goby density across sites and over time at three of four sites. Negative effects were most pronounced on the biomass of gastropods. Benthic algal biomass increased with goby density across sites, suggesting a trophic cascade driven by the impacts of gobies on gastropods and other algivores. Our study highlights the potential ecosystem impacts of an expanding goby population in a large river.

scholarly journals A future without stocking? The importance of harvest and river regulation for long-term population viability of migratory salmonids

2019 ◽  
Author(s):  
Chloé Rebecca Nater ◽  
Marlene Wæge Stubberud ◽  
Øystein Langangen ◽  
Atle Rustadbakken ◽  
S. Jannicke Moe ◽  
...  
Keyword(s):  
Size Structure ◽  
Human Impacts ◽  
Population Decline ◽  
Population Viability ◽  
Mitigation Measures ◽  
Life History Stage ◽  
Compensatory Mitigation ◽  
Projection Model ◽  
Quantitative Models

1. Humans are influencing animal and plant populations both directly (e.g.through harvest) and indirectly by altering environments. For many exploitedspecies, stocking with captive-bred individuals is a common strategy tomitigate negative human impacts and sustain populations over time. However,accumulating knowledge of negative side effects of stocking calls for quantificationof consequences and exploration of sustainable alternatives.2. Evaluating alternative management strategies using quantitative models iscentral to conservation. Here, we investigate the effects of several managementstrategies on a population of landlocked, migratory brown trout (Salmotrutta) inhabiting a large lake and spawning in a dammed river. We assess thepopulation level consequences of terminating a long-term stocking programmeand evaluate whether the loss of artificial recruitment may be compensatedby changes in harvest regulations and/or river habitat improvement.3. We build an integral projection model (IPM) classifying individuals bybody size, life history stage, and location relative to the hydropower damand parameterised it with 50 years of individual-based data supplementedwith literature values. We first analyse the model to assess size, structure,and relative importance of different mortality components across life stagesand locations in trout populations with and without stocking. We theninvestigate potential responses of an unstocked population to managementactions involving different sets of harvest rules, reductions in dam passagemortality, and improvements of spawning habitat below the dam.4. Our model predicts a strong population decline of 12–21% per year in theabsence of stocking. This decline is largely attributed to high harvest mortality,and drastic reductions in fishing pressure thus necessary to ensure populationviability without stocking. Reducing mortality associated with passage of thehydropower dam and restoring spawning areas has only small positive effectson population growth. Nonetheless, these mitigation measures can contributeto population viability when combined with changes in harvest regulations.5. Intensely harvested populations may rely heavily on the addition of captive-bredindividuals, and our results indicate that premature termination of stockingprogrammes can be detrimental without compensatory mitigation measuressuch as harvest reductions and habitat improvements. It is therefore crucialto collect necessary data and assess the impacts of alternative managementstrategies using quantitative models prior to making decisions.

scholarly journals Trends in body condition of smallmouth bass and northern pike (1982–2013) following multiple ecological perturbations in the St. Lawrence River

2017 ◽  
Vol 74 (8) ◽  
pp. 1158-1172 ◽  
Author(s):  
Derek P. Crane ◽  
John M. Farrell
Keyword(s):  
Invasive Species ◽  
Environmental Change ◽  
Body Condition ◽  
Round Goby ◽  
Northern Pike ◽  
Smallmouth Bass ◽  
Neogobius Melanostomus ◽  
Dreissenid Mussels ◽  
Time Periods ◽  
St Lawrence River

Body condition indices can be used to investigate fish response to biological or environmental change. We used quantile regression to analyze a 32-year weight–length data set (1982–2013) for smallmouth bass (Micropterus dolomieu) and northern pike (Esox lucius) from the St. Lawrence River to examine changes in condition (weight-at-length) during three ecologically distinct time periods. Condition of both species varied among time periods, with smallmouth bass experiencing greater proportional changes than northern pike. Smallmouth bass weight-at-length was greatest during 2005–2013 and lowest during 1982–1992. Northern pike weight-at-length was greatest during 2005–2013 for quantiles ≥0.5, similar between the 1982–1992 and 2005–2013 time periods for lower quantiles, and lowest during 1993–2004. The most likely weight–length model for smallmouth bass included terms for length, presence of round goby (Neogobius melanostomus), presence of dreissenid mussels, and an interaction between length and dreissenid mussels (wi = 0.93). The most likely model for northern pike included terms for length, presence of round goby, presence of dreissenid mussels, water temperature, conspecific abundance, and sex (wi = 0.56). Invasive species and environmental change related to invasive species have altered the condition of smallmouth bass and northern pike in the St. Lawrence River.

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