Early Life Stage Mortality Syndrome in Fishes of the Great Lakes and Baltic Sea

1998 ◽  
Keyword(s):  
Thiamine Deficiency ◽  
Lake Michigan ◽  
Lake Trout ◽  
Control Diet ◽  
Lake Superior ◽  
Life Stage ◽  
Early Life Stage ◽  
Alosa Pseudoharengus ◽  
Commercial Diet ◽  
Early Mortality Syndrome

<em>Abstract</em>.—Juvenile and adult lake trout <em>Salvelinus namaycush </em>that were fed semipurified, thiaminedeficient diets or alewives <em>Alosa pseudoharengus </em>containing thiaminase, a thiamine-destroying enzyme, showed no overt symptoms of thiamine deficiency. Growth rates and ovulation rates were similar among all treatments. However, liver thiamine pyrophosphate (TPP), a biochemical indicator of impending thiamine deficiency, in juvenile lake trout fed thiamine-deficient diets was reduced to 35 pmol/ g compared with 59 pmol/g in control groups. Blood TPP in adult female lake trout fed alewives was one-third of that in controls fed a commercial diet. Adult lake trout from Lake Michigan had blood TPP levels similar to those of fish fed the alewife diet in the laboratory. Lake Superior lake trout had TPP levels similar to those of fish fed the control diet in the laboratory. Thiamine synthesis occurred in the intestine of lake trout. At least 81% of thiamine in the posterior intestine was synthesized, presumably by bacteria, when a <sup>14</sup>C-labeled thiamine diet was force-fed to lake trout. Thiamine had a long retention time in the lake trout: at 27 weeks after fish were injected with radioactive thiamine, blood cells retained 11% of the radioactivity that was present at 2 d and liver tissue retained 34% of the 2-d level. Lack of self-sustaining lake trout reproduction by Lake Michigan fish may be related to their lower blood thiamine levels. Thiamine deficiency may cause early mortality syndrome, which is common in Lake Michigan but not Lake Superior fish with higher blood thiamine levels.

Early Life Stage Mortality Syndrome in Fishes of the Great Lakes and Baltic Sea

1998 ◽  
Keyword(s):  
Great Lakes ◽  
Baltic Sea ◽  
Early Life ◽  
Lake Trout ◽  
Life Stage ◽  
Early Life Stage ◽  
Early Mortality ◽  
Thiamine Pyrophosphate ◽  
Critical Threshold ◽  
Early Mortality Syndrome

<em>Abstract</em>.—Dietary amprolium, a thiamine antagonist, was fed to lake trout <em>Salvelinus namaycush </em>broodstock from April to October before spawning to determine its effect on egg and tissue concentrations of thiamine, thiamine monophosphate, and thiamine pyrophosphate. The thiamine concentration of eggs from fish fed no amprolium was 61.8 nmol/g, whereas the concentration of thiamine in fish fed 0.05 and 0.10% amprolium was 4.02 and 1.71 nmol/g (<EM>P </EM>< 0.01), respectively. In lake trout fed 0.10% amprolium beginning in August, egg free thiamine concentration was reduced to 11.6 nmol/g. No sign of early mortality syndrome was observed in sac fry from eggs in this study, which suggests that thiamine concentrations in the egg were not low enough to be below a critical threshold or that factors other than thiamine are involved in early mortality syndrome.

Early Life Stage Mortality Syndrome in Fishes of the Great Lakes and Baltic Sea

1998 ◽  
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Lake Trout ◽  
Life Stage ◽  
Lake Ontario ◽  
Early Life Stage ◽  
Fertilization Success ◽  
Thiamine Pyrophosphate ◽  
Predictive Index ◽  
Early Mortality Syndrome

<em>Abstract</em>.—Reproductive success and vitamin B<sub>1 </sub>(thiamine pyrophosphate, thiamine monophosphate, and free thiamine) concentrations were assessed in feral female lake trout <em>Salvelinus namaycush </em>from Lake Ontario and Lake Manitou. We monitored fertilization success, survival to hatch, incidence of blue-sac disease, other anomalies, and lake trout early mortality syndrome (EMS). Fertilization and hatching success were high, whereas mortality from blue-sac disease and other anomalies was low in egg batches from both lakes. There was no mortality from EMS in families from Lake Manitou. However, EMS occurred after hatching in the offspring of 48% of the females collected from Lake Ontario. We measured thiamine in liver, red blood cells, eggs, and developing embryos. Relative to fish collected in reference lakes, females in Lake Ontario had depressed hepatic, red blood cell, and egg thiamine concentrations. Although more extensive investigation of thiamine balance is required, it may be possible to use red blood cell thiamine pyrophosphate as a predictive index for EMS susceptibility in offspring. Total thiamine concentrations in developing embryos declined by 50% between fertilization and swim-up. Free thiamine reserves declined most rapidly, whereas levels of thiamine pyrophosphate increased between the eyed embryo and hatch stages. A high proportion (67%) of lake trout families in which the initial egg free thiamine reserves or embryonic concentrations of thiamine pyrophosphate levels were <0.8 nmol/g exhibited EMS. Below this threshold (0.8 nmol/g), the occurrence of EMS was variable (0–100%) and only weakly related to free thiamine concentrations (<em>r</em><sup>2</sup> = 0.32, <EM>P</EM> = 0.014). This observation implies the possibility of additional interactions with other factors.

Early Life Stage Mortality Syndrome in Fishes of the Great Lakes and Baltic Sea

1998 ◽  
Keyword(s):  
Ascorbic Acid ◽  
Lake Michigan ◽  
Coho Salmon ◽  
Life Stage ◽  
Dehydroascorbic Acid ◽  
Early Life Stage ◽  
High Survival ◽  
Survival Group ◽  
Chromatography Analysis ◽  
Early Mortality Syndrome

<em>Abstract.—</em>Muscle and egg samples from returning adult female Lake Michigan coho salmon <em>Oncorhynchus kisutch </em>were collected for thiamine analysis. Three groups of five females having low (2.5%), medium (42.4%), or high (92.6%) mean fry survival were selected for this study. Egg and muscle samples were collected at spawning and analyzed by high-performance liquid chromatography analysis for free thiamine, thiamine monophosphate (TP), and thiamine pyrophosphate (TPP). Egg concentrations of ascorbic acid, iron, zinc, magnesium, and potassium were measured. Twenty-five contaminants were also measured in muscle tissue of adult females. Total thiamine levels in eggs were similar between the medium and high survival groups but significantly lower in the low survival group. Eggs from the high and medium survival groups had higher levels of free thiamine and TP (<EM>P </EM>< 0.01) than eggs from the low survival group. There were no significant differences among the three groups in egg TPP. Muscle concentrations of TPP, TP, and total thiamine were similar among the three survival groups (<EM>P </EM>> 0.10). Correlations between fry survival and egg free thiamine (<em>r </em>= 0.61) and TP (<em>r </em>= 0.52) were observed. Fry survival was not correlated with adult muscle concentration of any form of thiamine or contaminant measured. Among the three groups, no differences in egg concentration were found for ascorbic acid, dehydroascorbic acid, iron, magnesium, zinc, and potassium. This research supports the hypothesis that low egg thiamine is an important factor in early mortality syndrome.

Linking Egg Thiamine and Fatty Acid Concentrations of Lake Michigan Lake Trout with Early Life Stage Mortality

2009 ◽  
Vol 21 (4) ◽  
pp. 262-271 ◽  
Author(s):  
Sergiusz Czesny ◽  
John M. Dettmers ◽  
Jacques Rinchard ◽  
Konrad Dabrowski
Keyword(s):  
Fatty Acid ◽  
Early Life ◽  
Lake Michigan ◽  
Lake Trout ◽  
Life Stage ◽  
Early Life Stage

Early Life Stage Mortality Syndrome in Fishes of the Great Lakes and Baltic Sea

1998 ◽  
Keyword(s):  
Great Lakes ◽  
Yellow Perch ◽  
Lake Trout ◽  
Life Stage ◽  
Osmerus Mordax ◽  
Alosa Pseudoharengus ◽  
Rainbow Smelt ◽  
Inland Lakes ◽  
Early Mortality Syndrome ◽  
Thiamine Content

<em>Abstract</em>.—Lake trout <em>Salvelinus namaycush </em>eggs were collected from 18 separate locations in the Great Lakes and inland lakes to evaluate the relationship between diet and egg thiamine content. Thiamine concentrations in the eggs of lake trout whose diet consisted primarily of rainbow smelt <em>Osmerus mordax </em>and alewife <em>Alosa pseudoharengus </em>were one-ninth to one-seventeenth those of eggs of lake trout whose diet lacked either of these two species and was composed of lake herring <em>Coregonus artedi</em>, yellow perch <em>Perca flavescens</em>, cyprinids, or invertebrates. Within the Great Lakes, concentrations of thiamine in the eggs of lake trout increased in the order Ontario, Erie, Michigan, Huron < Superior and reflected the proportion of smelt, alewives, or both in the diet. Of the three forms of thiamine found in eggs, free thiamine was the most important and the form most affected by a diet of alewives or smelt. Collections from inland lakes were similar in terms of thiamine content and its relationship to diet composition. Average free thiamine concentrations in lake trout from Lakes Ontario, Erie, Michigan, and Huron were 1.5 to 4 times a threshold of 0.8 nmol/g that has been associated with the development of a thiamine-responsive early mortality syndrome. In contrast, the concentration of free thiamine in Lake Superior lake trout eggs was 26 times the threshold. We concluded that the reduction in egg thiamine concentrations in lake trout whose diet was primarily smelt or alewives was the result of their high thiaminase content, because published thiamine contents could not explain the patterns observed. Egg thiamine concentrations in lake trout were unaffected by maternal age.

Early Life Stage Mortality Syndrome in Fishes of the Great Lakes and Baltic Sea

1998 ◽  
Keyword(s):  
Great Lakes ◽  
Baltic Sea ◽  
Early Life ◽  
Lake Superior ◽  
Life Stage ◽  
Early Life Stage ◽  
Whole Body ◽  
Osmerus Mordax ◽  
Alosa Pseudoharengus ◽  
Sampling Times

<em>Abstract</em>.—Smelt <em>Osmerus mordax </em>and alewives <em>Alosa pseudoharengus </em>were collected from Lakes Huron and Michigan in spring and fall and from Lake Superior in spring to determine the activity of thiaminase, a thiamine-destroying enzyme, in those species. Greater thiaminase activity was found in the viscera (1,902 pmol • g<sup>-1</sup> • min<sup>-1</sup> for smelt and 1,705 pmol • g<sup>-1</sup> • min<sup>-1</sup> for alewives) than in the eviscerated body (180 pmol • g<sup>-1</sup> • min<sup>-1</sup> for smelt and 235 pmol • g<sup>-1</sup> • min<sup>-1</sup> for alewives). The average whole body thiaminase activity when all of the samples were pooled was 362 pmol • g<sup>-1</sup> • min<sup>-1</sup> for smelt and 357 pmol • g<sup>-1</sup> • min<sup>-1</sup> for alewives. Large differences were found in thiaminase activities between smelt and alewives from different locations in the Great Lakes region and at different sampling times. These differences may be species-, location-, or season-specific.

Early Life Stage Mortality Syndrome in Fishes of the Great Lakes and Baltic Sea

1998 ◽  
Keyword(s):  
Lake Michigan ◽  
Coho Salmon ◽  
Life Stage ◽  
Early Life Stage ◽  
Early Mortality ◽  
Thiamine Hydrochloride ◽  
Predisposing Factor ◽  
Early Mortality Syndrome ◽  
Salmon Eggs ◽  
The Mean

<em>Abstract</em>.—Lake Michigan Skamania strain steelhead <em>Oncorhynchus mykiss </em>and coho salmon <em>O. kisutch </em>fry exhibit an early mortality syndrome (EMS) in which death is preceded by loss of equilibrium, inability or lack of feeding, and general lethargy. It was hypothesized that decreased egg concentrations of carotenoid pigments, thyroxine, or thiamine contributed to this syndrome. Thiamine analyses of Lake Michigan coho salmon eggs from individual family groups exhibited 16–97% EMS if egg total thiamine concentrations were less than 0.9 nmol/g or egg free thiamine concentrations were less than 0.3 nmol/g. In eggs with total or free thiamine concentrations greater than 0.9 or 0.3 nmol/g, respectively, the range of EMS in fry was 5–12%. Immersion of steelhead and coho salmon eggs in 1.4 mM or greater thiamine hydrochloride significantly decreased EMS compared with controls. Immersion of coho salmon eggs in 2.8 mM thiamine increased the mean concentration of free thiamine in the eggs to 1.0 nmol/g, compared with 0.26 nmol/g in controls. Injection of either β-carotene or astaxanthin (0.86 or 8.6 µg/g, respectively) in steelhead eggs did not significantly reduce the occurrence of EMS. Early mortality syndrome was not decreased in steelhead after immersion of eggs in 2 mg/L thyroxine, but it was significantly decreased in steelhead sac fry immersed in 2 mg/L thyroxine. These results suggest that low egg thiamine is a predisposing factor for EMS; however, other factors that are variable among individual coho salmon females may influence the occurrence of EMS-related mortality. Whether the addition of exogenous thiamine corrects a thiamine deficiency or protects fry from developing EMS through some other mechanism is currently unknown.

An Energetics Model for Lake Trout, Salvelinus namaycush: Application to the Lake Michigan Population

1983 ◽  
Vol 40 (6) ◽  
pp. 681-698 ◽  
Author(s):  
Donald J. Stewart ◽  
David Weininger ◽  
Donald V. Rottiers ◽  
Thomas A. Edsall
Keyword(s):  
Lake Michigan ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
High Energy ◽  
Alosa Pseudoharengus ◽  
Fishing Mortality ◽  
Age Classes ◽  
Short Term ◽  
Conversion Efficiencies

An energetics model is implemented for lake trout, Salvelinus namaycush, and applied to the Lake Michigan population. It includes an egestion function allowing any proportional mix of fish and invertebrates in the diet, a growth model accounting for both ontogenetic and seasonal changes in energy-density of predator and prey, a model for typical in situ swimming speed, and reproductive energy losses due to gametes shed. Gross conversion efficiency of energy by lake trout over their life (21.8%) is about twice the efficiency of converting biomass to growth because they store large amounts of high-energy fats. Highest conversion efficiencies are obtained by relatively fast-growing individuals, and over half the annual energy assimilated by older age-classes may be shed as gametes. Sensitivity analysis indicates a general robustness of the model, especially for estimating consumption by fitting a known growth curve. Largest sensitivities were for the intercept and weight dependence coefficients of metabolism. Population biomass and associated predatory impact of a given cohort increase steadily for about 3.5 yr then decline steadily after fishing mortality becomes important in the fourth year in the lake. This slow response time precludes manipulation of lake trout stocking densities as a means to control short-term prey fluctuations. Predation by lake trout on alewife, Alosa pseudoharengus, has been increasing steadily since 1965 to about 8 400 t∙yr−1, and is projected to rise to almost 12 000 t∙yr−1 by 1990.

Early Life Stage Mortality Syndrome in Fishes of the Great Lakes and Baltic Sea

1998 ◽  
Keyword(s):  
Great Lakes ◽  
Prey Species ◽  
Lake Trout ◽  
Life Stage ◽  
Species Variation ◽  
Osmerus Mordax ◽  
Alosa Pseudoharengus ◽  
Rainbow Smelt ◽  
Thiamine Content ◽  
Lake Variation

<em>Abstract</em>.—Thiamine concentrations in representative Great Lakes prey fish, including alewives <em>Alosa pseudoharengus</em>, rainbow smelt <em>Osmerus mordax</em>, slimy sculpin <em>Cottus cognatus</em>, bloater chub <em>Coregonus hoyi</em>, and lake herring <em>Coregonus artedi</em>, and their major dietary items, including mysids <em>Mysis relicta</em>, amphipods <em>Diporeia hoyi</em>, and net macroplankton, were measured to assess their potential involvement in depressed thiamine concentrations in lake trout <em>Salvelinus namaycush </em>of the Great Lakes. Mean thiamine concentrations in all biota were greater than the recommended dietary intake of 3.3 nmol/g for prevention of effects on growth, although the adequacy of these concentrations for reproduction is not known. Mean thiamine concentrations decreased in the order alewives > bloater chub, herring > smelt and differed from the order of associated egg thiamine concentrations published for lake trout feeding on these species (herring > alewives, smelt). As a result, these data strongly implicate the high thiaminase content, rather than the low thiamine content, of alewives and smelt as being responsible for the low egg thiamine concentrations of Great Lakes lake trout stocks that feed heavily on these species. Variations in thiamine content among prey species did not appear to be related to levels in their diet, because thiamine concentrations in <em>Mysis</em>, <em>Diporeia</em>, and macroplankton showed little consistency between group or between lake variation. There was no lake to lake variation in mean thiamine concentrations of prey species, but considerable within species variation occurred that was unrelated to size.

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