Effects of salinity and heat-shock on wheat seedling growth and content of carbohydrates,proteins and amino acids

The effects of salinity (0, 50, 100, 150, and 200 mM NaCl) and heat-shock (42°C) and their interactions on germination, seedling growth, and some relevant metabolic changes of two cultivars (cv. Giza 155 and cv. Stork) of wheat (Triticum vulgaris L.) were studied. Germination studies indicate that plants tolerated salinity up to 100 mM NaCl. The lengths of roots and shoots and their water content, as well as fresh and dry matter yield of cv. Giza 155 seedlings remained more or less unchanged up to 100 mM NaCl and of cv. Stork up to 50 mM NaCl. Salinity induced progressive increase in soluble carbohydrates, soluble proteins and proline in cv. Giza 155 and in soluble proteins, proline and other free amino acids in cv. Stork. However, under the higher salinity levels, in cv. Giza 155 increase in soluble carbohydrates was accompanied by lose in other free amino acids, whereas in cv. Stork an opposite effect was obtained. Heat-shock treatment (42°C for 24 h) induced a significant decrease in the final germination percentage, the shoot and root lengths, fresh matter yield and the water content. The dry matter yield of the two cultivars was considerably increased as compared with the corresponding treatments with NaCl only. Heat-shock treatment resulted in a significant increase, in the amount of soluble carbohydrates and proline in salt treated seedlings of both cultivars. The pattern of changes in amino acids was opposite to that of soluble proteins, indicating that the increase in soluble proteins was at the expense of other amino acids in cv. Giza 155 andvice versa in cv. Stork.     

Temperature affects the limitation of Daphnia magna by eicosapentaenoic acid,and the fatty acid composition of body tissue and eggs

1. Poikilothermic animals incorporate more polyunsaturated fatty acids (PUFAs) into their cellular membranes as temperature declines, suggesting an increased sensitivity to PUFA limitation in cool conditions. To test this we raised Daphnia magna at different temperatures and investigated the effect of varying dietary PUFA on life history parameters (i.e. growth, reproduction) and the PUFA composition of body tissue and eggs. 2. Upon a PUFA‐rich diet (Cryptomonas sp.) females showed higher concentrations of several ω3 PUFAs in their body tissue at 15 °C than at 20 °C and 25 °C, indicating a greater structural requirement for ω3 PUFAs at low temperature. Their eggs had an equal but higher concentration of ω3 PUFAs than their body tissue. 3. In a life history experiment at 15 and 20 °C we supplemented a diet of a PUFA‐free cyanobacterium with the ω3 PUFA eicosapentaenoic acid (EPA). The growth of D. magna was more strongly EPA limited at low temperature. A greater requirement for structural EPA at 15 °C was indicated by a steeper increase in somatic EPA content with dietary EPA compared to 20 °C. 4. At 20 °C the development of eggs to successful hatching was high when EPA was supplied to the mothers. At 15 °C the hatching success was generally poor, despite of a higher maternal provision of EPA to eggs, compared to that at 20 °C, suggesting that EPA alone was insufficient for proper neonatal development at the low temperature. The growth of offspring from mothers raised at 20 °C without EPA supplementation was very low, indicating that the negative effects of EPA deficiency can be carried on to the next generation. 5. The fatty acid composition of Daphnia sp. in published field studies shows increasing proportions of saturated fatty acids with increasing environmental temperature, whereas ω3 PUFAs and EPA show no clear pattern, suggesting that variations in dietary PUFA may mask temperature‐dependent adjustments in ω3 PUFA concentrations of cladocerans in nature.     

Resource partitioning between pelagic coregonids in a subarctic watercourse following a biological invasion

If a pelagic ecosystem is invaded by an efficient planktivorous fish, competition theory predicts that habitat and/or diet segregation should occur if the invader and native planktivores are to co-exist. We compared the diet and pelagic habitat use between invading vendace (Coregonus albula) and two native morphs of whitefish (Coregonus lavaretus) in three subarctic lakes located within the same watercourse. No clear vertical habitat segregation was found as vendace prevailed throughout the entire depth range. Zooplankton generally dominated the diet of all three coregonids. No obvious resource partitioning was found in two of the lakes, while in the third lake the diets of whitefish and vendace differed significantly from each other. Here, the predominant pelagic whitefish morph fed extensively on water mites whereas vendace mainly consumed surface insects and to some extent small fish, apparently as a result of highly depleted zooplankton resources. The results suggest that various levels of resource depletion following the vendace invasion caused the observed differences between the lakes, indicating that different levels of resource partitioning were associated with dissimilar competition intensities. At present, coexistence of these congeneric species seems to be possible, although the vendace invasion has apparently resulted in a challenging and unstable situation for the planktivorous whitefish.     

Genetic differentiation of coregonid fishes in pechora river

A population–genetic study of five coregonid fish species has been carried out using 30 enzyme loci. The species under study included whitefish, a natural hybrid of vendace and least cisco, inconnu, peled, and Arctic cisco. The investigation revealed a low intraspecific genetic differentiation of the abovementioned species from Lower Pechora River and Usa River, which is the main tributary in the Pechora River basin, where coregonid fishes migrate to spawn. Presumably, whitefish, vendace, and inconnu inhabiting the main channels of Lower Pechora and Usa rivers are represented here by introgressive populations of species formed by a mix of discrete evolutionary lineages originating from geographically separated Late Quaternary refugia. Some lineages of whitefish, vendace, and inconnu from the West Siberian periglacial lake came to Eastern Europe together with the last migration wave of Siberian species to the west, including peled, broad whitefish, and Arctic cisco, during the Middle Weichselian glaciation (60000–50000 years ago), while in the Eastern European Periglacial refugium (Lake Komi), local lineages of these species had survived. The periglacial Lake Komi has probably been located on the Pechora Plain since early Weichselian glaciation (90000–80000 years ago), and the studied whitefish specimens from Upper Pechora River are probably the purest descendants of the periglacial race of whitefish from Lake Komi. This assumption is supported by the data on the high level of genetic differentiation between the whitefish of Upper Pechora and Lower Pechora (D _N = 0.005), as well as by the pattern of allele distribution in some polymorphic loci. In our opinion, the ecologic and genetic differentiation of vendace in the Pechora River basin is also connected with the interaction between two evolutionary lineages that originated from independent periglacial refugia.     

The influence of food competition and host specificity on the transmission of Triaenophorus crassus (Cestoda) and Cystidicola farionis (Nematoda) to Coregonus lavaretus and Coregonus albula (Pisces:Coregonidae) in Finland

As a superior competitor for planktonic food, vendace (Coregonus albula), when abundant, is expected to displace whitefish (Coregonus lavaretus) from feeding on plankton and to force it to rely more on benthic food. The predicted result would be a reduced abundance of the copepod-transmitted cestode Triaenophorus crassus in whitefish, but an increase in the abundance of the nematode Cystidicola farionis transmitted via benthic amphipods. We studied the occurrence of both parasites in whitefish during 1991-1996 in three interconnected areas at Lake Saimaa, Finland, where the densities of the vendace stocks varied due to natural fluctuation in year-class strengths. In accordance with our hypothesis, some indication of the effect of the density of the vendace population on abundance of C. farionis infection in whitefish was found, but not in the case of T. crassus. Only 0.2% of vendace were infected with T. crassus, while up to 100% of the whitefish in the yearly samples harboured the parasite. In further experiments we clarified which copepod species in Lake Saimaa act as first intermediate hosts of T. crassus, and verified from stomach samples the exposure of both whitefish and vendace to those species. Experimental infections indicated that the infectivity of T. crassus is lower for vendace than for whitefish. We suggest that the reason why vendace stock density does not affect T. crassus infection in whitefish is that T. crassus is transmitted in littoral areas during a short period in spring. At that time of the year copepods are abundant and available to both whitefish and vendace, but since the parasite is less infective to vendace. they do not become infected. At other times of the year, dense vendace stocks may force whitefish to shift to benthic food, which includes amphipods transmitting C. farionis. During vendace stock decline, whitefish may, however, continue to feed on plankton and avoid exposure to C. farionis.     

Studies in the biochemistry of cirripede eggs. IV. The free Amino-acid pool in the eggs of Balanus balanoides (L.) and B. balanus (L.) during development

Changes in the ‘free’ amino acids, betaine, and trimethylamine oxide during the development of the eggs of Balanus balanoides (L.) and B. balanus (L.) have been determined; the results are given in terms of μM/g dry wt, μM/g water, and μM/10⁶ eggs. The amino acids are derived from the yolk proteins the net composition of which is known. Free amino acids are present in considerable quantity, as is commonly the case with crustacean tissue. Changes in the individual amino acids are discussed. B. balanus eggs contain large, and relatively constant, amounts of sarcosine; its function is unknown but large quantities are present in the more highly evolved cirripedes so far examined. A possible relation between betaine glycine, and sarcosine relative to choline metabolism is considered. Large amounts of taurine are present. There is a striking increase in β-alanine in the late stages of development; in B. balanoides it comes to be the most, and in B. balanus the third most common amino acid; its possible involvement in purine metabolism is considered. The relation between the amounts of the various entities in the eggs and in the bodies of the adult are examined.     

Artificial incubation of California condor Gymnogyps californianus eggs removed from the wild

The currrent California condor (Gymnogyps californianus) recovery plan entails increasing the reproductive rate via replacement-clutch manipulation of eggs. During the period from 1983 to 1985, 15 eggs were removed from wild nesting pairs for artificial incubation. The eggs were incubated at a dry bulb temperature of 36.4°C in modified forced-air Lyon Electric incubators. The incubation humidity was adjusted for individual eggs based on weight loss data (water = weight), 25.6–30.0°C wet bulb (41.0–63.0% Relative Humidity (RH)). The chicks were hatched initially under forced-air conditions of 36.1°C dry bulb, 31.1–01.7°C wet bulb (70.0–73.0% RH). In 1984, hatching parameters were changed to still-air conditions, 36.1°C dry bulb (top of the egg), 35.0°C dry bulb (bottom of the egg), 31.1–31.7°C wet bulb (70.0-73.0% RH). Tactile and auditory stimulation was utilized during the pip-to-hatch interval. From among 15 eggs collected, 13 hatched, and 12 condor chicks were raised successfully (hatchability: 86.7%; survivability: 92.3%).     

Does water calcium content influence the distinctness of daily growth increments in the otoliths of larval whitefish (Coregonus lavaretus L.)?

In larval and juvenile whitefish ( Coregonus lavaretus L.) from Lake Constance, Germany, the otolith increments are deposited daily, whereas daily deposition could not be confirmed in larval whitefish from Lake Pyhäselkä, Finland. The calcium concentration in Lake Constance is high (around 1.3 m m ), while calcium deficiency is typical for Finnish lakes (around 0.15 m m ). Therefore, the hypothesis that the distinctness of daily otolith increments in whitefish is related to water calcium content was tested by rearing three groups of Lake Constance whitefish in water of 0.2, 1.3 and 4.7 m m Ca. The eggs were incubated in lake water (1.3 m m Ca), and the larvae were acclimated to the experimental calcium concentrations on the day of hatching. After 39 days of ad libitum- feeding with Artemia nauplii, the three groups did not differ significantly in total length, wet and dry weight, and otolith length and width. The daily increments were easily recognizable, and contrast between dark (D)- and light (L)-zones was the same in the fish of all test groups. For the experimental set-up of this study, and particularly the range of calcium concentrations tested, the hypothesis that water calcium content influences the distinctness of daily otolith increments was rejected.     

Zur fortpflanzungsbiologie von mesostoma ehrenbergii (Focke, 1836) (Turbellaria)

1. At temperature levels from 10 to 25°C animals from resting eggs produce subitaneous eggs independent on temperature. In contrast animals from subitaneous eggs produce subitaneous eggs dependent on temperature. At a high rate subitaneous eggs are only formed at temperature levels above 20°C.
2. Below 10°C no development occurs in the juveniles. At temperatures of 30/22°C (24.7°C) the first subitaneous eggs are formed after 6–9 days, at 14/9°C (10.7°C) they are formed after 34 days. At different temperature levels the developmental rate of the young is from 10.5 to 42 days. One generation extends over 16.5 (30/22°C) to 75 days (14/9°C). The average egg production is 10–20 subitaneous eggs or 30–60 resting eggs. The maximum egg production of one individual is 50 subitaneous eggs or 84 resting eggs. 50% of the animals have just formed resting eggs, before the juveniles are hatched. Resting eggs in the first egg-batch are formed 6–20 days later than subitaneous eggs. The duration of life is between 65 (30/22°C) and 140 days (19/13°C).
3. Young worms in resting eggs have a dormance period of at least 15–30 days.

At room temperatures (20°C) no juvenile in resting eggs hatches from water. By combining room and refrigerator (3.5°C) temperatures the hatching rate increases to a maximum of 85%. To reach a hatching rate of 50–65% the influence of low temperatures must be at least 30 days. At room temperatures 60% of the young in resting eggs hatch from mud covered with water. Combining high and low temperatures the hatching success is between 67 and 81%, where the highest percentage of the young may hatch at room temperature. Up to 90 days low temperatures cause a maximum hatching rate of 79%. It decreases to approximately 30% after 180 days. At high temperatures resting eggs preserved in 100% moist mud, survive for two months. By adding a period of low temperatures the hatching rate increases to a maximum of 52%. Low temperatures are survived for more than 6 months. Up to 30 days preservation at 3.5°C causes a maximum hatching rate of 61%, up to 12o days it decreases to 30%. At room temperature the young in resting eggs are not resistant against air-dried mud (30–40% rel. air moisture). Combining high and low temperatures air-dried mud is endured 1 month (hatching rate 5–14%). Preservation of 30–120 days at 3.5°C and 70% rel. air moisture result in a hatching rate of 43–61%. li]4. In the open air in Middle-Europe there occur 5–6 generations of M. ehrenbergii per life-cycle. The first generation hatches from resting eggs in May, where the production of subitaneous eggs is independent on temperature. All other generations up to October hatch from subitaneous eggs. The egg-production of those worms is dependent on environmental factors. In summer subitaneous egg production prevails, in autumn resting egg production. The abundance during the life-cycle is dependent on the number of animals which produce subitaneous eggs. Resting eggs are predestinated to endure periods of dryness and cold. The life-cycles of the species M. lingua and M. productum are different from those of M. ehrenbergii in length and in the number of generations. In both species 7 generations occur over 8 to 8.5 respectively 5.5 months. M. nigrirostrum only forms resting eggs. The life-cycle consists of one generation from February/March to May/June.     

Changes in growth,proteins and free amino acids of developing seed and pod of fenugreek

The growth and development under field conditions of the pods and seeds of two cvs of Trigonella foenum graecum are described. Samples were harvested at different stages of ripeness for the determination of dry matter, protein and free amino acid content. During maturation, reserves of solutes are established in the pod wall before the seeds begin their exponential phase of growth. Later, these reserves disappear, providing about 20% of the seed's requirements for nitrogen. SDS-electrophoresis was used to follow the formation of proteins and it was shown that the synthesis of storage proteins takes place prior to dehydration of the seed. Production soluble nitrogenous compounds precedes protein accumulation. Free amino acids follow the same pattern. 4-Hydroxyisoleucine represents nearly 80% of free amino acid of dry seeds. The concentration does not decrease in the later stages of maturation of the seed but this unusual amino acid is absent in the storage proteins of the seeds.     

Synchrony in the hatching of eggs in the desert locust <Emphasis Type="Italic">Schistocerca gregaria</Emphasis> (Orthoptera: Acrididae): egg condition influences hatching time in the laboratory and under simulated field temperatures

This study examined the time of hatching of the desert locust Schistocerca gregaria Forskål (Orthoptera: Acrididae) in the laboratory to test the effect of eggs within a pod versus individualized eggs. The pod organization of eggs is thought to play a role in controlling hatching time and to facilitate synchronous hatching at constant temperatures. In the present study, we examined the hatching times of eggs in a pod and individualized eggs under 24-h thermocycles and simulated field temperatures. We tested two patterns of thermocycles consisting of a 12-h thermoperiod (35 or 30 °C) and 12-h cryoperiod (low temperature period; 30 or 25 °C), and two patterns of field temperatures observed in a natural habitat, Mauritania, in May and September. The majority of eggs hatched during low temperature periods in all patterns tested. In addition, the variances of hatching times for individualized eggs were significantly greater than for egg pods in which a clear peak of time of hatching was observed. We show that egg condition influences hatching time under thermocycles of constant and fluctuating temperatures in the laboratory, and may play a role in the adaptive time of hatching.     

The biology of the West African bush-cricket,Euthypoda acutipennis Karsch (Orthoptera: Tettigoniidae)

This paper presents the results of the first comprehensive study of the biology of a tropical bush-cricket. The eggs were laid without any external protective structures and lost water readily in unsaturated air; losses of more than 16% of the original fresh weight were usually fatal. Development and hatching took place only if the eggs were in contact with water. The water content increased by about 500% during development. The mean incubation period was 171 and 116 days at constant temperatures of 20^oC and 28^oC, respectively, but at temperatures fluctuating by±3°C about a mean of 28°C this period was reduced to a mean of 88 days. The eggs failed to develop if exposed to freezing temperatures for more than five days or kept at a constant temperature of 307deg;C or above. The duration of the nymphal period varied from 83 to 131 days at a temperature range of 22–30°C (mean 26° C). There were four or five nymphal instars in the male and five or six in the female. The linear growth of the hind femur conformed to Dyar's law. There was a conspicuous colour change during development, all the first-instar nymphs being leaf green and the adults predominantly brown. In nature the species lives exclusively on the forest floor and is markedly nocturnal in habits, hiding underneath litter during the day. The eggs are dormant during the dry season, hatching at the onset of the rains (March/April at Ibadan). The nymphs reach maturity from July onwards and the adults have mostly died off by the end of the rainy season (October). In the laboratory the species was found to have a temperature preference of 26–32°C, immobilization setting in at 18°C and 42°C, and a humidity preference of 60–80% R.H.; this corresponds with the prevailing conditions in its forest habitat. The nocturnal pattern of activity persisted for several days in continuous darkness, with no marked acceleration. Movement was inhibited for several days by artificial illumination. Reversed illumination reversed the rhythm of activity.     

In vitro rearing ofTrissolcus basalis [Hym., Scelionidae] an egg parasitoid ofNezara viridula [Hem., Pentatomidae]

In vitro rearing of the egg parasitoidTrissolcus basalis (WOLL.) from eggs collected on the natural hostNezara viridula (L.) was initiated. Several oligidic diets containing insect material (Manduca sexta hemolymph or host egg content) were tested. Our initial medium with 50% hemolymph induced a high egg mortality, but by decreasing the hemolymph concentration, increasing the hen egg yolk concentration and adding 15% of free amino acids mixture, a hatching rate of 85% of the parasitoid eggs was obtained with 39% reaching the second instar and 33% the third instar. In a medium without hemolymph, but with 18% liquid from parasitized host eggs we obtained 90% to 100% hatching, 25 to 27% reaching the second instar and 8% the third instar. We did not obtain pupation from eggsin vitro, but did get pupae and adults from larvae rearedin vivo to second instar and transfered to anin vitro system.      

Developmental Changes in the Free Amino Acid Pool and Total Protein Amino Acids of Pea Cotyledons (Pisum sativum L.)

Changes in the levels of twenty-two free amino acids and in the amino acid composition of the total protein were measured throughout the development of cotyledons of a dwarf garden pea, Pisum sativum cv Greenfeast, grown in a constant environment. A sensitive double-isotope dansylation technique was used. Fresh weight, dry weight, and protein content were also followed. Twenty of the amino acids showed synchronous changes in levels, giving a developmental pattern containing four peaks; major peaks occurred very early and very late in development. The amino acid composition of the total protein, which was always very different from that of the free amino acid pool, showed early changes to one consistent with the final storage protein composition of the seed. These changes included a 50% drop in methionine content and a 70% rise in cysteine. While the maximum free methionine level occurred early in development, that of cysteine was late.     

The effects of starvation on the sodium, potassium, water and free amino acid content of parietal muscle from Agonus cataphractus.

1. The levels of the individual free amino acids, K, Na and water present in parietal muscle were measured in fish starved for periods of 3-115 days. 2. The Na and water content progressively increased relative to dry weight of tissue during the starvation period whereas an initial increase in the K content up to 67 days was followed by a decrease to near the normal fed level by 115 days. The ammonia content remained essentially stable over the same period. 3. The essential free amino acid content tended to follow the muscle sodium pattern while the non-essential amino acids and taurine gave results somewhat similar to those of potassium. 4. The net result of these changes is that the Na, K and total free amino acid concentration is maintained within fairly narrow limits relative to the tissue water content during 11-67 days of the starvation period under the experimental conditions used.     

Variation in the content of free amino acids in body fluids of freshwater mollusk Lymnaea stagnalis during seasonal adaptation to low positive temperatures

The effect of autumn and winter decrease in environmental temperature on the content of free amino acids in body fluids has been studied in freshwater snail Lymnaea stagnalis. In autumn, when temperature drops to 4 and 0°C, the highest increase in alanine concentration was observed and its pool was almost three times that in summer. A less pronounced accumulation of glutamate, glycine, histidine, and serine was observed in the same temperature range. Cysteine was detected at 0°C. The accumulation of essential amino acids methionine, leucine, isoleucine, tyrosine, and phenylalanine took place at 0°C, while only traces of these amino acids were detectable at 4°C. At the same time, free lysine undetectable in summer has been revealed in autumn at 4°C and its concentration increased as temperature decreased to 0°C. In winter, when the mollusks were hypermetabolic for 2.5 months, the pools of all amino acids decreased 4–8 times, while essential amino acids (except lysine) were undetectable. The involvement of alanine and, possibly, lysine in L. stagnalis adaptation to near-zero temperature is proposed.     

Biochemical strategy of survival of the freshwater mollusc <Emphasis Type="Italic">Lymnaea stagnalis</Emphasis> at near-zero temperatures

Effect of an autumn-winter decrease of the environmental temperature on changes of the content of free amino acids and reducing sugars was studied in tissues fluids of the freshwater mollusc L. stagnalis. At a decrease of the temperature to 4 and 0°C at the autumn period, concentration of free alanine rose several times; an increase of histidine, glutamate, glycine, and serine concentrations was less pronounced. Accumulation of methionine, leucine, isoleucine, tyrosine, and phenylalanine was revealed at 0°C. In the state of long hypobiosis (at 4°C), pools of all amino acids fell 4–8 times; essential amino acids, except for lysine, were not detected at all. Both at the summer and at the autumn periods, high concentrations of free fructose and glucose were revealed. In the process of hypobiosis the fructose pool decreased almost 35, while the glucose pool—12 times. Maltose that was absent in summer was found at 4 and 0°C as well as after 2.5 months of hypobiosis. The changes of the studied parameters in L. stagnalis in response to hypothermia are compared with the corresponding parameters of changes in cryoresistant animals in response to negative temperatures.     

Adaptive difference in daily timing of hatch in two locust species,Schistocerca gregaria and Locusta migratoria: The effects of thermocycles and phase polyphenism

This study examined the effects of temperature and phase polyphenism on egg hatching time in the desert locust, Schistocerca gregaria, and the migratory locust, Locusta migratoria. The two species exhibited differences and similarities in hatching behavior when exposed to different temperature conditions. In 12-h thermocycles of various temperatures, the S. gregaria eggs hatched during the cryoperiod (low temperature period), whereas L. migratoria eggs hatched during the thermoperiod (high temperature period). The eggs of both species hatched during the species-specific period of the thermoperiod in response to a temperature difference as small as 1 °C. Furthermore, the locusts adjusted hatching time to a new thermal environment that occurred shortly before the expected hatching time. In both species, the hatching of the eggs was synchronized to a specific time of the day, and two hatching peaks separated by approximately 1 day were observed at a constant temperature after the eggs were transferred from thermocycles 3 days before hatching. Eggs laid by gregarious females hatched earlier than those laid by solitarious females in S. gregaria but this difference was not observed in L. migratoria.     

黄鳝含肉率及氨基酸成分分析

测定了黄鳝的含肉率及其氨基酸含量 ,对其营养价值进行了评定。该鱼 (鲜样 )含肉率 75 .12 % ;水分 6 2 .9% ;肌肉粗蛋白 (g/10 0g干样 ) 74.5 6 % ;水解氨基酸总量 5 6 .11% ;其中必需氨基酸 2 0 .83% ;占氨基酸总量的 37.12 %。认为黄鳝是一种营养价值和养殖价值都比较高的淡水养殖鱼类 ,具有良好的开发利用前景。     

Egg quality and female condition in vendace (Coregonus albula L.) before and during spawning

The fat content of muscle, liver and eggs of vendace (Coregonus albula L.) were measured during the maturation of ovaries in summer. The fat content of eggs was at its highest in July and that of muscle in August during the optimal feeding season. Significant differences were not found in fat content between lakes Suvasvesi and Southern-Kallavesi in central Finland. There were no essential differences in fatty acid composition between muscle, liver and eggs of Lake Suvasvesi vendace. During the last month before spawning in October the gross energy and fat contents of eggs decreased in Lake Suvasvesi vendace. The fat and vitamin C contents of muscle as well as the liver index of females decreased during this time also. In males the corresponding decrease did not occur, indicating that spawning is a greater stress for females than for males. The egg quality and condition of Lake Inarijärvi vendace were about the same as those of Lake Suvasvesi vendace. The unfavourable conditions of Lake Inarijärvi, located in northern Finland, are reflected in the size of ovaries, which is known to be smaller (gonadosomatic index < 20%) than in Lake Suvasvesi (GSI 26–27%). Vendace, then, maintain the quality of eggs at the expense of their number.