Racial differences in eggs and juveniles of Windermere charr, Salvelinus alpinus

At least four races of charr occur in Windermere, the largest natural lake in England: north basin and south basin autumn spawners, north basin and south basin spring spawners. This study examines racial differences between eggs and juveniles, and relates juvenile size and survival to egg size. There were no major differences between races for egg incubation times and the percentage of eggs hatching successfully, the latter being high (mean values 76–96%) with a negligible proportion of abnormal alevins (<0.8%). Although there were no significant differences in the lengths of the female parents, both eggs and alevins were significantly larger for the autumn spawners than the spring spawners. Size differences in alevins, especially live weight, were positively related to egg size but not female parent size. Mean percentage survival for juveniles attaining the independent feeding stage was higher for the progeny of autumn spawners (32%) than spring spawners (3%). Racial differences in the egg and alevin stages therefore appear to have a significant effect on subsequent survival, and could be ultimately responsible for the relatively small proportion of spring spawners (only 4–6%) in the Windermere population of charr.     

Prevalence and effect of spawner-isolated mortality virus on the hatchery phases of Penaeus monodon and P. merguiensis in Australia

Spawner-isolated mortality virus (SMV) has been associated with mortalities in broodstock of Penaeus monodon and with mid-crop mortality syndrome on grow-out farms. Epidemiological evidence suggested an association between the SMV status of broodstock and subsequent survival of their progeny, and this paper describes investigations into that association. The faeces of 909 broodstock in 9 different groups were tested by a polymerase chain reaction (PCR) for SMV and positive results were confirmed by an internal dot-blot. Seventy-seven spawners (8.5%) were positive for SMV with prevalence ranging from 0 to 24% among groups. The prevalence in spawners of P. monodon was higher (24%) than in P. merguiensis (4%). Three longitudinal studies were undertaken to compare the survival of progeny from broodstock that were positive to SMV with those that were not. Survival in hatchery tanks of progeny from SMV-positive spawners was lower than those from SMV-negative spawners with reductions of 23% (p = 0.01), 7.3% (p = 0.214) and 18.9% (p = 0.129) in the 3 studies. The conclusions were less consistent when examined during each of the later stages of growth in hatchery pools, nursery and grow-out ponds, with progeny from SMV-postive spawners sometimes having better survival rates. However, survival was better overall in progeny from SMV-negative spawners. Simple linear regression showed survival was negatively related to the proportion of postlarvae from SMV-positive spawners, with a decrease in survival of 5.6% for each 10% increase in the proportion of postlarvae coming from SMV-positive spawners (p = 0.006). Data from 38 ponds showed 6.71% of losses were due to SMV. If these losses were consistent across the entire industry, the annual loss due to SMV would have been approximately AUD 3 million in 1999/2000.     

Importance of ontogenetic habitat shifts to juvenile output and life history of Atlantic salmon in a large subarctic river: an approach based on analysis of scale characteristics

Juvenile and adult scale characteristics were used to compare two juvenile groups of Atlantic salmon in a large subarctic river in northern Scandinavia: individuals that have migrated from the main stem into small tributaries and those which remain in the main stem. Body size and scale measurements indicated enhanced growth in migratory parr as compared to their resident main stem counterparts. Analysis of adult salmon scale characteristics using maximum likelihood estimators revealed that 20% of the adults had been in the tributaries before the end of their second year of life, and more than 30% more had moved into the tributaries in the third year. Tributary fish matured at a smaller size and younger age (one-sea-winter salmon) than those rearing in the main stem which included a higher proportion of multi-sea-winter salmon. In addition, when smolt ages and ages at maturity were compared, older female smolts often resulted in smaller spawners and younger smolts, larger spawners. Small female spawners were more likely to survive to become repeat spawners.     

Trade-off between egg mass and egg number in brown trout

Individual egg mass and fecundity increased with somatic mass in first time and repeat spawning wild anadromous and freshwater resident brown trout Salmo trutta . The egg mass was larger for similar-sized trout in south (58° N) than mid Norway (63° N), whereas fecundity was higher in mid- than in south Norway, making total gonadal investment similar in the two areas. Repeat spawners had heavier eggs than similar-sized first time spawners. The egg mass of residents was c. 10% larger than that of similar-sized first time spawning anadromous trout. Common garden experiments with offspring of wild anadromous trout showed no significant correlation between egg and somatic mass in first time spawners in two of the three populations studied. In the third population, a slight positive correlation was found. Similar results were found for repeat spawners. In the three populations, fecundity increased significantly with somatic mass in both first time and repeat spawners. Wild and hatchery-reared trout showed negative correlation between egg mass and fecundity when the effect of body size was excluded, indicating a trade-off between the two parameters. In wild trout, this was caused by variation among populations, whereas in hatchery fish, within population variation was observed in egg mass over fecundity. Furthermore, the egg mass of first time and repeat spawners were positively correlated, when adjusted for fish size. Size-specific gonadal investment was significantly higher in wild anadromous than resident trout. There was no significant difference in gonadal investment between first time and repeat spawners in wild anadromous trout. However, in the hatchery-reared trout, gonadal investment was significantly higher at repeat than first time maturation. The hatchery trout did not spawn naturally, but were artificially stripped. Among populations, a part of the variation in egg mass and fecundity is phenotypically plastic, a part appears genetically determined.     

Size‐dependent reproductive success of wild zebrafish Danio rerio in the laboratory

Size‐dependent reproductive success of wild zebrafish Danio rerio was studied under controlled conditions in the laboratory to further understand the influence of spawner body size on reproductive output and egg and larval traits. Three different spawner size categories attained by size‐selective harvesting of the F₁‐offspring of wild D. rerio were established and their reproductive performance compared during a 5 day period. As to be expected, large females spawned more frequently and had significantly greater clutch sizes than small females. Contrary to expectations, small females produced larger eggs when measured as egg diameter with similar amounts of yolk compared to eggs spawned by large spawners. Eggs from small fish, however, suffered from higher egg mortality than the eggs of large individuals. Embryos from small‐sized spawners also hatched later than offspring from eggs laid by large females. Larval standard length (L_S)‐at‐hatch did not differ between the size categories, but the offspring of the large fish had significantly larger area‐at‐hatch and greater yolk‐sac volume indicating better condition. Offspring growth rates were generally similar between offspring from all size categories, but they were significantly higher for offspring spawned by small females in terms of L_S between days 60 and 90 post‐fertilization. Despite temporarily higher growth rates among the small fish offspring, the smaller energy reserves at hatching translated into lower condition later in ontogeny. It appeared that the influence of spawner body size on egg and larval traits was relatively pronounced early in development and seemed to remain in terms of condition, but not in growth, after the onset of exogenous feeding. Further studies are needed to explore the mechanisms behind the differences in offspring quality between large‐ and small‐sized spawners by disentangling size‐dependent maternal and paternal effects on reproductive variables in D. rerio.     

Spawning success in Atlantic salmon (Salmo salar L.): a long-term DNA profiling-based study conducted in a natural stream

Spawning success of Atlantic salmon (Salmo salar L.) was investigated, under near-natural conditions, in the Girnock Burn, an 8-km long tributary of the River Dee in Scotland. Employing minisatellite-based DNA profiling, mating outcomes were resolved over three spawning seasons by assigning parentage to progeny samples removed from spawning nests ('redds'). While individual spawning patterns differed markedly, consistent trends were present over the 3 years studied. Multiple spawning was found to be prevalent. More than 50% of anadromous spawners of both sexes contributed to more than one redd. Up to six redds for a single female and seven for a single male were detected. Both sexes ranged extensively. Distance between redds involving the same parent varied from a few metres to > 5 km. Distances > 1 km were common. Both males and females ranged to a similar extent. Range limit was not correlated to fish size. Pairs were not monogamous, both males and females mating with different partners at different sites. Size assortative mating was apparent among 1991 spawners but was not detected for 1992 or 1995. Redd superimposition was found to be common (17-22% of redds over the 3 years), although it was not correlated to the number of anadromous spawners present. High levels of nonanadromous mature parr mating success (40-50% of total progeny sampled) were recorded, and these likely contribute greatly to the effective population size. The relevance of these findings at the individual and population level is discussed, with particular reference to management implications.     

The growth of charr, Salvelinus willughbii Günther, in Windermere

The growth of charr ( Salvelinus willughbii Günther ) caught in Windermere from 1941–1952 has been studied. Scales were used for determination of age and back-calculation of length for age. Autumn and spring spawners, males and females, and charr of normal and dwarf growth were treated separately. In fish of normal growth, the spring spawners were significantly smaller than the autumn spawners at ages 1 and 2 years, and significantly larger from age 4 years onwards. There was little difference in growth between males and females within the two spawning populations. Charr of lengths of less than 200 mm at age 4 years were considered to be dwarfs. Mean lengths at capture of male charr were: autumn spawners normal growth 272 mm, dwarf 218 mm; spring spawners normal growth 327 mm, dwarf 194 mm. The oldest recorded age was 8 years.     

Using parentage analysis to estimate rates of straying and homing in Chinook salmon (Oncorhynchus tshawytscha)

We used parentage analysis based on microsatellite genotypes to measure rates of homing and straying of Chinook salmon (Oncorhynchus tshawytscha) among five major spawning tributaries within the Wenatchee River, Washington. On the basis of analysis of 2248 natural‐origin and 11594 hatchery‐origin fish, we estimated that the rate of homing to natal tributaries by natural‐origin fish ranged from 0% to 99% depending on the tributary. Hatchery‐origin fish released in one of the five tributaries homed to that tributary at a far lower rate than the natural‐origin fish (71% compared to 96%). For hatchery‐released fish, stray rates based on parentage analysis were consistent with rates estimated using physical tag recoveries. Stray rates among major spawning tributaries were generally higher than stray rates of tagged fish to areas outside of the Wenatchee River watershed. Within the Wenatchee watershed, rates of straying by natural‐origin fish were significantly affected by spawning tributary and by parental origin: progeny of naturally spawning hatchery‐produced fish strayed at significantly higher rates than progeny whose parents were themselves of natural origin. Notably, none of the 170 offspring that were products of mating by two natural‐origin fish strayed from their natal tributary. Indirect estimates of gene flow based on F_ST statistics were correlated with but higher than the estimates from the parentage data. Tributary‐specific estimates of effective population size were also correlated with the number of spawners in each tributary.     

Intra-annual variation in the batch fecundity of sardine off Portugal

Atresia in the ovaries of sardine Sardina pilchardus did not show clear seasonal patterns. There was high prevalance ( c. 60%) and low intensity ( c. 1% of gonadal area occupied by oocytes) in all months of the spawning season studied. The batch size to ovary-free mass relationship was significantly different in the mid-spawning season, with higher relative fecundity and gonadosomatic index (I_G) in January than in November and March. There was no additional effect on batch fecundity due to age or condition factor. Data from monthly market samples during 1998–1999 revealed a continuous decline of the condition factor throughout the spawning season. The market samples also revealed that the duration of the spawning season is not equal for all fish. In any month, pre-spawning fish tended to have significantly higher I_G than spawners, indicating that delayed initiation of spawning can lead to larger relative fecundity. The increase in sardine relative fecundity during the first half of the spawning season is probably due to the continuous influx of new spawners and possibly to body mass loss that is initially not translated into gonad mass loss. After January when all visible fat reserves within the body cavity have disappeared, the influx of new spawners practically ceases.     

Previously spawned Atlantic salmon ascend a large subarctic river earlier than their maiden counterparts

Spawning migration timing of maiden Atlantic salmon Salmo salar and previous spawners was analysed in the catches in 1989–2004 in the large subarctic River Teno in the northernmost parts of Finland and Norway. The hypothesis was that the migration timing of previous spawners and their maiden counterparts is similar, with the migration timing similar between sexes. In most cases, however, previous spawners were observed to migrate into the River Teno and its tributaries earlier than their maiden counterparts. The difference in run timing was especially evident between maiden one-sea-winter (1SW) Atlantic salmon and the corresponding group of previous spawners [1S1, 1 year at sea (1) followed by first spawning (S) and reconditioning period of 1 year (1) at sea and second spawning run] for both sexes in the River Teno and in its two tributaries. The same was also evident between 2SW maiden and 2S1 previous spawning female Atlantic salmon in the River Teno. Females showed earlier spawning migration than males both in previous spawners and maiden Atlantic salmon. Different maiden sea-age classes also showed differences in run timing as multi-sea-winter fish (2–4SW) ascended earlier than 1SW fish but the timing of 1S1 and 2S1 previous spawning females coincided. The results suggest that run timing of Atlantic salmon may not be strictly genetically fixed as previous spawners ascend earlier than they did on their first spawning migration as maiden fish, and indicated that the closeness of the reconditioning area of postspawners to the river of origin resulted in an early ascent. Run timing of different sea-age groups has major management implications if the populations are heavily exploited with numerous fishing methods in different periods of the fishing season, as in the River Teno system.     

The impact of supplementation in winter-run chinook salmon on effective population size

Supplementation of young raised at a protected site, such as a hatchery, may influence the effective population size of an endangered species. A supplementation program for the endangered winter-run chinook salmon from the Sacramento River, California, has been releasing fish since 1991. A breeding protocol, instituted in 1992, seeks to maximize the effective population size from the captive spawners by equaling their contributions to the released progeny. As a result, the releases in 1994 and 1995 appear not to have decreased the overall effective population size and may have increased it somewhat. However, mistaken use of non-winter-run chinook spawners resulted in artificial crosses between runs with a potential reduction in effective population size, and imprinting of the released fish on Battle Creek, the site of the hatchery, resulted in limiting the contribution of the released fish to the target mainstem population. Rapid genetic analysis of captured spawners and a new rearing facility on the Sacramento River should alleviate these problems and their negative effect on the effective population size in future years.     

Comparison of maturation timing,egg size and fecundity between hatchery lines of chinook salmon and their wild donor stocks

Increasing concern has been expressed about the genetic effects of cultured salmonid fishes on natural populations. Avoidance of extreme negative outcomes was one reason for the establishment of a genetic management policy for the State of Alaska. However, domestication within the hatchery may still cause divergence from the wild donor population. This divergence could potentially lead to adverse impacts on wild stocks through straying and introgression. This study examines potential domestication in two Alaskan chinook salmon stocks. The Little Port Walter (LPW) Hatchery Chickamin River stock resulted from a small collection of wild broodstock in 1976. The LPW Unuk stock was founded with a larger number of individuals in 1976 and has had subsequent infusion of wild gametes. These lines have been maintained at LPW through ocean ranching of tagged smolts. Comparisons are made between the hatchery lines, progeny of wild chinook collected from the Chickamin and Unuk Rivers, and hybrids between the hatchery and wild groups. Mature ocean‐ranched female chinook salmon returning to the facility were periodically graded for ripeness and spawned. Body size and meristic measurements were collected from these mature spawners. Maturation timing, fecundity, and individual egg size of these fourth generation hatchery fish are compared with that of offspring of wild fish from the same donor stock. Stock of origin is confirmed for all spawners and offspring using microsatellite DNA analysis.     

To produce many small or few large eggs: a size-independent reproductive tactic of fish

Summary We demonstrate here the existence of a range of size-independent reproductive tactics in teleostean fish involving the allocation of a size-dependent reproductive effort between fecundity and egg size. Despite considerable evidence that larger eggs and the larvae hatching from them are more likely to survive than smaller ones, we found no evidence of evolutionary trends towards greater egg sizes. Fish with pelagic eggs tend to spawn many, and therefore small, eggs, whereas demersal spawners tend to produce large, and therefore few, eggs. Maximizing egg number should increase the number of eggs hatching in suitable locations in the patchy pelagic environment and, hence, increase the reproductive success of pelagic spawners. On the other hand, the reproductive success of demersal spawners, which reduce the variance in growing conditions experienced by the off spring, should be more dependent on the survival of the individual larvae, which increases as egg size increases.     

Consequences to fitness‐related traits of hybridization between farmed and wild Atlantic salmon, Salmo salar

Increasing concern has been expressed about the genetic effects of cultured salmonid fishes on natural populations. Avoidance of extreme negative outcomes was one reason for the establishment of a genetic management policy for the State of Alaska. However, domestication within the hatchery may still cause divergence from the wild donor population. This divergence could potentially lead to adverse impacts on wild stocks through straying and introgression. This study examines potential domestication in two Alaskan chinook salmon stocks. The Little Port Walter (LPW) Hatchery Chickamin River stock resulted from a small collection of wild broodstock in 1976. The LPW Unuk stock was founded with a larger number of individuals in 1976 and has had subsequent infusion of wild gametes. These lines have been maintained at LPW through ocean ranching of tagged smolts. Comparisons are made between the hatchery lines, progeny of wild chinook collected from the Chickamin and Unuk Rivers, and hybrids between the hatchery and wild groups. Mature ocean‐ranched female chinook salmon returning to the facility were periodically graded for ripeness and spawned. Body size and meristic measurements were collected from these mature spawners. Maturation timing, fecundity, and individual egg size of these fourth generation hatchery fish are compared with that of offspring of wild fish from the same donor stock. Stock of origin is confirmed for all spawners and offspring using microsatellite DNA analysis.     

Variability in condition and growth of Atlantic cod larvae and juveniles reared in mesocosms: environmental and maternal effects

Standard length, dry mass and RNA : DNA ratio measurements of 3876 Atlantic cod Gadus morhua larvae and juveniles from 26 families of recruit (fish during their first year of spawning) and repeat spawners (fish which were in their subsequent spawning season) reared in two mesocosms (2500 and 4400 m³) under semi-natural conditions were analysed over a period of 10 weeks using microsatellites. Larvae from recruit spawners were significantly longer and heavier at hatch and throughout the 10 weeks. RNA : DNA ratios from recruit spawner offspring were only significantly higher at week 1. The smaller (2500 m³) mesocosm was characterized by low plankton density during the transition from endogenous to exogenous feeding followed by a higher density during the metamorphosis period (weeks 4 and 5), with the reverse pattern evident in the 4400 m³ mesocosm. Patterns of larval growth followed patterns of zooplankton density. Significant differences in RNA : DNA ratios between the mesocosms at all comparable sampling dates were found and within each mesocosm individual fish exhibited a wide range of growth and condition responses under the same environmental conditions. RNA : DNA ratios as a function of size differed in the amount of variability between mesocosms, indicating that the higher food density led to a higher proportion of well-conditioned larvae in the first 3 weeks. Food availability probably has a major role in determining offspring growth and condition, with limited effects due to maternal effects in cases where the broodstock females are approximately of similar size and condition.     

Characteristics of the hatchery-reared Black Sea salmon <Emphasis Type="Italic">Salmo trutta labrax</Emphasis>

For conserving the unique representative of salmonids—the Black Sea salmon Salmo trutta labrax—its hatchery rearing was initiated in 1998 at the Adler trout hatchery farm (Northern Caucasia). Fish were kept in concrete tanks. The comparative assessment of hatchery-reared fish and salmon from natural populations revealed their similarity by dates of the onset of smoltification, ratio of spawners maturing at different ages, and the weight, sizes, and fecundity of females. The quality of sexual products and progeny obtained from spawners of the initial brood stock was high. The data obtained indicate that the method of hatchery rearing the Black Sea salmon is promising.     

Climate change impacts on mismatches between phytoplankton blooms and fish spawning phenology

Substantial interannual variability in marine fish recruitment (i.e., the number of young fish entering a fishery each year) has been hypothesized to be related to whether the timing of fish spawning matches that of seasonal plankton blooms. Environmental processes that control the phenology of blooms, such as stratification, may differ from those that influence fish spawning, such as temperature‐linked reproductive maturation. These different controlling mechanisms could cause the timing of these events to diverge under climate change with negative consequences for fisheries. We use an earth system model to examine the impact of a high‐emissions, climate‐warming scenario (RCP8.5) on the future spawning time of two classes of temperate, epipelagic fishes: “geographic spawners” whose spawning grounds are defined by fixed geographic features (e.g., rivers, estuaries, reefs) and “environmental spawners” whose spawning grounds move responding to variations in environmental properties, such as temperature. By the century's end, our results indicate that projections of increased stratification cause spring and summer phytoplankton blooms to start 16 days earlier on average (±0.05 days SE) at latitudes >40°N. The temperature‐linked phenology of geographic spawners changes at a rate twice as fast as phytoplankton, causing these fishes to spawn before the bloom starts across >85% of this region. “Extreme events,” defined here as seasonal mismatches >30 days that could lead to fish recruitment failure, increase 10‐fold for geographic spawners in many areas under the RCP8.5 scenario. Mismatches between environmental spawners and phytoplankton were smaller and less widespread, although sizable mismatches still emerged in some regions. This indicates that range shifts undertaken by environmental spawners may increase the resiliency of fishes to climate change impacts associated with phenological mismatches, potentially buffering against declines in larval fish survival, recruitment, and fisheries. Our model results are supported by empirical evidence from ecosystems with multidecadal observations of both fish and phytoplankton phenology.     

An empirical model for predicting microhabitat of 0+ juvenile fishes in a lowland river catchment

Summary Species-habitat relationships are an important aspect of fish life history, particularly in early ontogeny. To address the lack of information on the microhabitat use/requirements of European coarse fishes, particularly 0-group fishes in riverine systems, an empirical model was generated from data collected in the River Great Ouse catchment (UK). During 7 weeks in autumn 1990, data on young-of-the-year (0+) juvenile fishes and 15 environmental variables were collected at 2800 stratified, random point samples within 130 study sites (streams, rivers, side-channels, backwaters). Of 24 species of 0+ fish, only 10 were captured in 3% of non-null samples. Association analysis and canonical correspondence analysis of the samples-by-species (967×10) and samples-by-variables (967×15) data matrices revealed that the shallow, narrow, lotic, stony-pebbly channel microhabitat of riffles and runs was preferred by the progeny of substrate-spawning, substrate/plant-spawning and nest-guarding fishes. Moderately deeper and wider, sinuous channels, with slowto-moderate water velocities and medium-sized substrata were also favourable to progeny of substrate spawners. Assemblages of 0+ fish in deeper, wider, silted, trapezoidal-shaped channels with slow-to-lentic flowing water, i.e. channelised and regulated, were dominated by ubiquitous (plant/substrate) spawners.     

Breeding biology of a non-diadromous galaxiid, Galaxias vulgaris Stokell, in a New Zealand river

In the Glentui River, Canterbury, New Zealand, Galaxias vulgaris Stokell spawned in late winter and early spring (from July to September), the onset of spawning being temperature-dependent. No females matured in their first year, but 95 and 68 % of age 0+ males were mature in consecutive years. With the exception of one female, all fish aged 1 + and older spawned. In mature fish, overies reached nearly 23%, and testes 11%, of somatic weight. Maturity in males depended on size, whereas in females, age appeared to be the major factor affecting maturity. Recruitment eggs for next season's spawning were distinct from primary oocytes soon after the ripe eggs were shed. Egg numbers varied between 284 and 1911 per fish, and weight was the best indicator of fecundity. Sex ratios of whole samples were not significantly different from 1 : 1, but ratios of potential spawners revealed an excess of males, due mainly to the presence of age 0 + fish. Age0+ males probably play an important role in adverse conditions and act as a form of insurance by significantly increasing the proportion of ripe males, thereby ensuring that all eggs are fertilized. The nest, egg mass and behaviour during the spawning period are described. More than one female may lay eggs in each nest and it is probable that each egg mass receives sperm from more than one male. It is suggested that the presence of fewer and larger eggs in G. vulgaris , compared with the diadromous galaxiids, is the result of a more precise fertilization process.     

Parent–egg–progeny Relationships in Teleost Fishes: An Energetics Perspective

Age-related variations in chemical composition of egg matter were found in females in some studies, but they do not seem to be a universal phenomenon. In contrast, egg size can be well predicted from female age. The relationship has a parabolic shape, but the predicted size decrease of eggs from old females has not always been documented. Female size is an important contributor to egg size, both at intra- and inter-specific levels. Dependence of fecundity on body size has usually been described by a power function. A trade-off between egg number and size is considered in light of life history strategies. During a spawning season egg size may differ between successive batches, but lack of effects of egg batch sequence was reported in some studies. In yolk-feeding fish three discrete periods of elevated mortality are typically observed: shortly after egg activation, during hatching, and at final yolk resorption. The positive relationships between female size, egg size and offspring size/resistance to starvation and predation are a key pathway in parent–egg–progeny relationships. Both maternal and paternal effects contribute to the total survival of offspring, but they operate in different ways and at different times. In contrast to the importance of female size, no paternal size effects were revealed, but density and motility of spermatozoans were decisive. Typically, paternal effects diminish earlier in ontogeny. Major factors governing embryonic survival (fertilisation success and hatching success) differ from factors to which starvation mortality of yolk-feeding larvae is related. Embryonic survival is affected by female age via egg matter composition, by egg ripeness and paternal factors such as sperm density and motility. In contrast, starvation mortality of yolk-feeding larvae depends largely on female attributes (age, size and fecundity) via egg size, and, in some batch spawners, on egg batch sequence. Among teleost species egg size varies across a wide range (from 0.3 to 85–90 mm in diameter). Species that spawn large eggs are relatively rare. Caloric value of egg dry matter varies within a narrow range of 20–30 J mg⁻¹. Ecosystem and evolutionary components, and reproductive style are factors that contribute to egg endowment and yolk quality. During the last decade considerable progress was made in the methodology and understanding of paternal effect on progeny performance in fishes. This paper reviews these of parent–egg–progeny relationships.