Occurrence of Glugea hertwigi in Lake Erie Rainbow Smelt (Osmerus mordax) and Associated Mortality of Adult Smelt

1972 ◽  
Vol 29 (11) ◽  
pp. 1639-1641 ◽  
Author(s):  
Stephen J. Nepszy ◽  
Alex O. Dechtiar
Keyword(s):  
Lake Erie ◽  
Parasite Load ◽  
Osmerus Mordax ◽  
Microsporidian Parasite ◽  
Rainbow Smelt ◽  
West Central

The occurrence of cysts of Glugea hertwigi, a microsporidian parasite, in Lake Erie rainbow smelt (Osmerus mordax) has been monitored since 1960 when it was first recorded. Annual sampling has shown that an increasing proportion (up to 87.5% in 1971) of the smelt population has been infected.An unusually severe mortality among adult smelt occurred during early May, 1971, in western and west central Lake Erie. Sampling of dead and obviously stressed smelt revealed that 97.3% of the males and 76.7% of the females were heavily loaded with cysts in the intestines and gonads, respectively. It is suggested that the parasite load contributed to the unusual severity of the normal postspawning mortality.

Infection of American smelt in Lake Ontario and Lake Erie with the microsporidian parasite Glugea hertwigi (Weissenberg)

1972 ◽  
Vol 50 (9) ◽  
pp. 1183-1188 ◽  
Author(s):  
M. Chen ◽  
G. Power
Keyword(s):  
Digestive Tract ◽  
Lake Erie ◽  
Ovarian Tissue ◽  
Lake Ontario ◽  
Parasite Load ◽  
Sexual Differences ◽  
Striking Difference ◽  
Female Fish ◽  
Microsporidian Parasite ◽  
Male Fish

In samples taken monthly throughout the year the percentage of American smelt in Lake Ontario and Lake Erie containing cysts of Glugea hertwigi was 5.2% and 62.7% respectively. Sexual differences in incidence were observed, the significance of which was uncertain as results from the two lakes were contradictory.In male fish infection was almost entirely restricted to the digestive tract with few cysts in the liver, skin, and testes. In female fish the digestive tract and ovaries were similarly infected.Seasonal fluctuations in Glugea infection were obvious and seemed correlated with the gonadal cycle. In both sexes the highest parasite load corresponded with the onset of maturation.A striking difference in fecundity between the two smelt populations was attributed to the Glugea infection. In females parasite cysts replaced ovarian tissue, causing a reduction in the number of maturing eggs.

Population dynamics of rainbow smelt (Osmerus mordax) in Lakes Ontario and Erie: a modeling analysis of cannibalism effects

2000 ◽  
Vol 57 (8) ◽  
pp. 1594-1606 ◽  
Author(s):  
Brian F Lantry ◽  
Donald J Stewart
Keyword(s):  
Population Dynamics ◽  
Lake Erie ◽  
Lake Ontario ◽  
Osmerus Mordax ◽  
Time Step ◽  
Rainbow Smelt ◽  
Modeling Analysis ◽  
Daily Time Step ◽  
Annual Time ◽  
Daily Time

We used a stochastic stage-based matrix model (annual time step) and a bioenergetics model (daily time step) to simulate population dynamics, production, consumption, and conversion efficiency for rainbow smelt (Osmerus mordax) populations in Lakes Ontario and Erie. Cannibalism on young-of the-year (YOY) smelt by yearlings was the only scenario that reproduced alternate-year recruitment cycles observed in Lakes Ontario and Erie. Assuming constant survivorship and 5% variation in cannibalism, less than one YOY consumed per yearling smelt per year in both lakes could produce fluctuations greater than those observed. We found that at estimated daily mortality rates and during the pelagic phase of larvae only, 2% of the yearling smelt in Lake Erie and 5.1% in Lake Ontario need to consume one YOY per day to induce the observed abundance fluctuations. Bioenergetics simulations of alternating recruitment produced fluctuations in simulated values for annual gross production of approximately 6-7 and 31-59% for the Lake Ontario and Lake Erie smelt populations, respectively.

Energetic consequences of diet shifts in Lake Erie rainbow smelt (Osmerus mordax)

2005 ◽  
Vol 62 (1) ◽  
pp. 145-152 ◽  
Author(s):  
SL Parker Stetter ◽  
L D Witzel ◽  
L G Rudstam ◽  
D W Einhouse ◽  
E L Mills
Keyword(s):  
Lake Erie ◽  
Food Resource ◽  
Fork Length ◽  
Late Summer ◽  
Osmerus Mordax ◽  
Bythotrephes Longimanus ◽  
Rainbow Smelt ◽  
The 1960S ◽  
Diet Shifts ◽  
Bioenergetics Models

The diet of eastern Lake Erie rainbow smelt (Osmerus mordax) has changed since the 1960s, reflecting food resource shifts due to phosphorus reductions and the invasion of exotic species (dreissenid mussels and Bythotrephes longimanus). Since rainbow smelt growth was lower in the 1990s than in the 1960s, we considered diet changes as an explanation. A decrease in the proportion of zooplankton occurred in the summer (May–August) diet of two size classes (63–88 and 89–114 mm fork length) between 1961 and 1999. Within the zooplankton, the proportion of Bythotrephes increased. In spite of these changes, energy density (joules per gram) of the summer (June–August) diet has not changed since 1961. However, during the late-summer and fall, predation on Bythotrephes, and therefore the proportion of indigestible spines in the stomach, increases. Using bioenergetics models, we show that Lake Erie rainbow smelt could achieve 66%–155% greater growth between June and October if Bythotrephes spines were replaced with digestible prey items, resulting in end-of-season weights and lengths similar to the 1985–1990 period. Our results indicate that indigestible Bythotrephes spines may reduce growth by occupying space in the stomach but providing no nutritional value to the fish, thereby reducing the realized daily ration for rainbow smelt.

A Comparison of Spawning, Harvested, and Die-Off Rainbow Smelt, Osmerus Mordax, in Eastern Lake Erie

1981 ◽  
Vol 7 (2) ◽  
pp. 144-154 ◽  
Author(s):  
Samuel Nsembukya-Katuramu ◽  
Eugene K. Balon ◽  
Robin Mahon
Keyword(s):  
Lake Erie ◽  
Osmerus Mordax ◽  
Rainbow Smelt

scholarly journals Hypoxia’s impact on pelagic fish populations in Lake Erie: a tale of two planktivores

2020 ◽  
Vol 77 (7) ◽  
pp. 1131-1148
Author(s):  
Joshua P. Stone ◽  
Kevin L. Pangle ◽  
Steven A. Pothoven ◽  
Henry A. Vanderploeg ◽  
Stephen B. Brandt ◽  
...  
Keyword(s):  
Lake Erie ◽  
Cold Water ◽  
Pelagic Fish ◽  
Fish Populations ◽  
Commercial Fishing ◽  
Osmerus Mordax ◽  
Rainbow Smelt ◽  
Bottom Waters ◽  
Thermal Preferences

Whether bottom hypoxia has long-lasting consequences for pelagic fish populations remains speculative for most ecosystems. We explored hypoxia’s influence on two pelagic zooplanktivores in Lake Erie that have different thermal preferences: cold-water rainbow smelt (Osmerus mordax) and warm-water emerald shiners (Notropis atherinoides). To assess acute effects, we combined predictive bioenergetics-based modeling with field collections made across the hypoxic season in central Lake Erie during 2005 and 2007. To assess chronic effects, we related fishery-independent and fishery-dependent catches with hypoxia severity and top predator (walleye, Sander vitreus) abundance during 1986–2014. As our modeling predicted, hypoxia altered rainbow smelt movement and distributions, leading to avoidance of cold, hypoxic bottom waters. In response, diets shifted from benthic to pelagic organisms, and consumption and energetic condition declined. These changes were lacking in emerald shiners. Our long-term analyses showed rainbow smelt abundance and hypoxia to be negatively related and suggested that hypoxia avoidance increases susceptibility to commercial fishing and walleye predation. Collectively, our findings indicate that hypoxia can negatively affect pelagic fish populations over the long term, especially those requiring cold water.

Examination of possible taxonomic differences within Lake Erie rainbow smelt, Osmerus mordax (Mitchill)

1983 ◽  
Vol 61 (2) ◽  
pp. 326-338 ◽  
Author(s):  
Hugh R. MacCrimmon ◽  
Barra L. Gots ◽  
Ross R. Claytor
Keyword(s):  
Growth Rate ◽  
Lake Erie ◽  
Growing Season ◽  
Genetic Differences ◽  
Osmerus Mordax ◽  
Growth Data ◽  
Rainbow Smelt ◽  
Eastern Basin ◽  
Random Samples ◽  
Electrophoretic Data

Random samples of rainbow smelt, Osmerus mordax, from commercial summer trawl harvests in the Central and Eastern basins of Lake Erie are examined. Analysis of the meristic, morphometric, and electrophoretic data indicates no statistical evidence of genetic differences between basin populations. However, significant differences in size and growth data between basin populations occur and are attributed to differences in limnological conditions between basins which affect the time of spawning, length of growing season, and growth rate. Thus, these differences indicate an ecophenotypic distinction between the Central and Eastern Basin populations because of between-basin limnological dissimilarities.

scholarly journals Application of in situ target-strength estimations in lakes: examples from rainbow-smelt surveys in Lakes Erie and Champlain

2003 ◽  
Vol 60 (3) ◽  
pp. 500-507 ◽  
Author(s):  
L.G Rudstam ◽  
S.L Parker ◽  
D.W Einhouse ◽  
L.D Witzel ◽  
D.M Warner ◽  
...  
Keyword(s):  
Lake Erie ◽  
Growing Season ◽  
Target Strength ◽  
Fish Length ◽  
Osmerus Mordax ◽  
Rainbow Smelt ◽  
Acoustic Data ◽  
Size Groups ◽  
High Fish

Abstract Acoustic abundance of fish depends directly on the target strength (TS) of the fish surveyed. We analyzed 70 and 120 kHz acoustic data from two lakes with abundant rainbow-smelt (Osmerus mordax) populations. Using repeated surveys through the summer growing season, we derived a relationship between TS (dB) and fish length L (cm) at 120 kHz (TS = 19.9 log10 L − 67.8). Values for 70 kHz were similar. In situ TS increased with fish density, indicating a bias from accepting multiple targets at high fish densities. Correcting for this bias increased estimates of smelt abundance by up to 18% in Lake Erie and up to 100% in Lake Champlain. Multiple modes in the TS distributions observed for older fish do not reflect different size groups, as the same modes can be observed from measurements from a single fish. Smelt released gas bubbles during the evening ascent, and these bubbles had TS (−60 to −58 dB) within the range of TS observed from the fish. Gas-bubble release occurred mostly during the migration. Conducting surveys after the ascent is completed will decrease bias associated with counting bubbles as fish.

Hypoxia modifies planktivore–zooplankton interactions in Lake Erie

2012 ◽  
Vol 69 (12) ◽  
pp. 2018-2028 ◽  
Author(s):  
Steven A. Pothoven ◽  
Henry A. Vanderploeg ◽  
Tomas O. Höök ◽  
Stuart A. Ludsin
Keyword(s):  
Lake Erie ◽  
Osmerus Mordax ◽  
Large Prey ◽  
Bythotrephes Longimanus ◽  
Rainbow Smelt ◽  
Leptodora Kindtii ◽  
Vertical Distributions ◽  
Consumption Rates ◽  
High Concentrations ◽  
Zooplankton Production

We evaluated vertical distributions of fish and zooplankton, planktivore consumption, and prey production in Lake Erie during 2005 to determine how hypolimnetic hypoxia alters fish (i.e., rainbow smelt (Osmerus mordax) and emerald shiners (Notropis atherinoides)) and invertebrate planktivore (i.e., Bythotrephes longimanus and Leptodora kindtii) relationships with their mesozooplankton prey. Hypoxia concentrated 45%–76% of fish into a narrow (<2 m) metalimnetic layer, but only 3%–13% of zooplankton production was in this layer. The epilimnion may have served to some degree as a refuge for mesozooplankton because high temperatures may have excluded rainbow smelt. High concentrations of fish above the hypolimnion likely resulted in increased competition for large prey (i.e., predatory claodcerans). Although hypoxia did not result in overall high predation demands by planktivores relative to total zooplankton production, planktivore consumption rates within the metalimnion exceeded zooplankton production in that layer.

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