Spawning Groups Research Articles

Connectivity between Pacific halibut Hippoglossus stenolepis residing in the Salish Sea and the offshore population, demonstrated by pop-up archival tagging

Fisheries for Pacific halibut (Hippoglossus stenolepis) in the US Pacific Northwest support a variety of harvest sectors including some that are restricted to coastal offshore waters and others confined to the inland waters of the Salish Sea. Such restrictions have generated interest in the degree to which the Salish Sea represents an extension of the offshore population versus its potential to support an isolated stock. Here, twelve female Pacific halibut were tagged during boreal summer with pop-up archival transmitting (PAT) tags that were programmed to report during either the subsequent winter spawning period or late-spring feeding period. High-resolution depth data failed to produce evidence of spawning within the Salish Sea, while depth-temperature profiles were consistent with the departure of migrants between October and January. Final positions and at-liberty longitude estimates suggest that ~60% of the tagged fish departed the Salish Sea, with confirmed migrations to Canada and Alaska. The recapture in the southern Salish Sea of one fish whose tag had reported earlier from offshore Canadian waters demonstrated the occurrence of cyclic migrations. Evaluation of likely maturity status suggests that local demographics reflect either the cumulative effects of spawning migrations in which some emigrants remain offshore after departing the system, or some combination of enhanced growth or delayed maturity. These findings confirm that the Salish Sea does not represent a functionally-independent stock, but suggest that inshore waters may play a unique role by receiving recruits, rearing individuals to maturity, and exporting spawners to the offshore stock components, while retaining a proportion of site-faithful individuals with cyclic seasonal connectivity with offshore spawning groups.

Spawning patterns provide further evidence for multiple stocks of sardine (Sardinops sagax) off eastern Australia

AbstractPrevious studies have suggested that sardine, Sardinops sagax, off eastern Australia spawns across its entire range when habitat conditions are suitable. However, recent studies have suggested that separate sub‐populations and spawning groups may occur in the region. Spawning patterns off eastern Australia were investigated using data collected during nine ichthyoplankton surveys conducted between 1997–2015, and adult reproductive data obtained from ad hoc commercial sampling off New South Wales (NSW). The egg surveys covered the known distribution of sardine off eastern Australia and included year‐round sampling in the northern and southern parts of this range. Egg distributions and analysis of gonadosomatic indices identified two spatio‐temporally separate spawning groups; one occurring off southern Queensland to northern NSW during late winter and early spring, and a smaller group off eastern Tasmania to southern NSW during summer. Most eggs were collected from waters 50–90 m deep, with sea surface temperatures of 18–23°C. Additive modelling indicated depth was the most significant factor driving selection of spawning habitat, followed by the interaction of month and latitude. Low egg densities were recorded in waters between 34–37°S, despite conditions within the ranges suitable for spawning. The presence of two spawning groups of sardine off eastern Australia supports recent findings that two sub‐populations occur in the region. Findings of this study will help to optimise the spatio‐temporal extent of future egg surveys and further confirm the need to coordinate future management of each sub‐population among relevant jurisdictions.

Genetic Divergence of Nearby Walleye Spawning Groups in Central Lake Erie: Implications for Management

AbstractSpawning‐site philopatry may lead to genetic differentiation among reproductive populations, despite their locations being in close proximity within single bodies of water. Identifying and maintaining locally differentiated spawning groups of Walleye Sander vitreus constitute an agency management priority of the multi‐agency Walleye Task Group advisory for the Great Lakes Fishery Commission. Although genetically separable spawning groups of Walleyes have been identified from several areas in the Great Lakes, those in central Lake Erie were previously unknown. The Ohio Division of Wildlife (ODW) collected Walleyes for the present analysis from two spawning groups in Lake Erie's central basin, located just 2 km apart—one in the Grand River, Ohio, and the other at the nearby central basin reef. The hypothesis of whether the two spawning groups were genetically different was tested by analyzing variation at 14 nuclear DNA microsatellite loci from Walleyes (n = 147) reproducing in 2012 at the two sites and among three separate years (1996, 2003, and 2012) in the Grand River (to evaluate temporal trends). Results revealed relatively high genetic diversity in both spawning groups, with the reproductive population in the Grand River having significantly greater allelic richness and representation of private alleles. The Grand River Walleye runs showed a slight temporal decline in allelic richness from 1996 to 2003, which coincided with ODW reports of declining numbers of Walleyes reproducing there. The two spawning groups differed in genetic composition suggesting that they are closely related, yet are separable reproductive subpopulations, with both contributing to the overall diversity of Lake Erie Walleye. Their maintenance and integrity thus may need management attention and further monitoring.

Using Genetic and Phenotypic Comparisons to Evaluate Apparent Segregation among Kokanee Spawning Groups

AbstractGenetic and phenotypic traits of spatially and temporally segregated kokanee Oncorhynchus nerka spawning groups in Lake Pend Oreille, Idaho, were compared to test for evidence of divergence on the basis of ecotype (stream spawners versus shoreline spawners) and spawn timing and to describe morphological, life history, and reproductive variation within and among groups. Early and late spawning runs were found to be reproductively isolated; however, there was no clear evidence of genetic differentiation between ecotypes. Spawning groups within the same ecotype differed in length, age distribution, mean length at age, fecundity, and egg size. Variation in reproductive attributes was due primarily to differences in length distributions. Larger‐bodied shore‐spawning kokanee were located in areas where egg survival is known to be enhanced by downwelling, suggesting that the distribution of shore‐spawning kokanee may be partly structured by competition for spawning habitats with groundwater influence. This study contributes to other research indicating that introduced kokanee populations are unlikely to undergo adaptive divergence if they have a history of population fluctuations and are supplemented regularly.

Analysis of shape variability and life history strategies of Illex argentinus in the northern extreme of species distribution as a tool to differentiate spawning groups

ABSTRACTThis study aimed to differentiate local and migratory spawning groups of the shortfin squid Illex argentinus caught in Brazilian waters using geometric and traditional morphometric methods and size-selective processes. The back-calculated length distributions reconstructed from daily growth increments deposited in the gladius allowed the identification of size-selective processes that may be related to different life history strategies. Landmark analysis on body shape (geometric morphometric) revealed that spawning groups presented significant ontogenetic variations in terms of body outline. In addition, traditional morphometric methods, based on multivariate analysis, associated juveniles of the expected migratory group (large size) and differentiated them from the local group individuals (small size). The changes in form, probably linked to the environmental gradients experienced by individuals throughout ontogeny, were interpreted as adaptations to improve swimming capacity. Migrant individuals have being differentiated from the smaller sizes group by body characteristics (broad fins, elongated and thicker mantle), which may increase the ability to perform long migrations.

Using Genetic and Phenotypic Comparisons to Evaluate Apparent Segregation among Kokanee Spawning Groups

Using Genetic and Phenotypic Comparisons to Evaluate Apparent Segregation among Kokanee Spawning Groups

Genetic differentiation of spring-spawning and fall-spawning male Atlantic sturgeon in the James River, Virginia.

Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus, Acipenseridae) populations are currently at severely depleted levels due to historic overfishing, habitat loss, and pollution. The importance of biologically correct stock structure for effective conservation and management efforts is well known. Recent improvements in our understanding of Atlantic sturgeon migrations, movement, and the occurrence of putative dual spawning groups leads to questions regarding the true stock structure of this endangered species. In the James River, VA specifically, captures of spawning Atlantic sturgeon and accompanying telemetry data suggest there are two discrete spawning groups of Atlantic sturgeon. The two putative spawning groups were genetically evaluated using a powerful microsatellite marker suite to determine if they are genetically distinct. Specifically, this study evaluates the genetic structure, characterizes the genetic diversity, estimates effective population size, and measures inbreeding of Atlantic sturgeon in the James River. The results indicate that fall and spring spawning James River Atlantic sturgeon groups are genetically distinct (overall FST = 0.048, F’ST = 0.181) with little admixture between the groups. The observed levels of genetic diversity and effective population sizes along with the lack of detected inbreeding all indicated that the James River has two genetically healthy populations of Atlantic sturgeon. The study also demonstrates that samples from adult Atlantic sturgeon, with proper sample selection criteria, can be informative when creating reference population databases. The presence of two genetically-distinct spawning groups of Atlantic sturgeon within the James River raises concerns about the current genetic assignment used by managers. Other nearby rivers may also have dual spawning groups that either are not accounted for or are pooled in reference databases. Our results represent the second documentation of genetically distinct dual spawning groups of Atlantic sturgeon in river systems along the U.S. Atlantic coast, suggesting that current reference population database should be updated to incorporate both new samples and our increased understanding of Atlantic sturgeon life history.

Temporal Variation in Shell Growth Rate of CockleAnadara granosain Relation with its Reproductive Cycle

A study was conducted on the relationship between the reproductive cycle and shell growth rate of Anadara granosa (Linnaeus, 1758). Gonadal maturity stages, increment width, and environmental factors were examined by means of a field enclosure experiment in Balik Pulau, Penang Island, Malaysia, from December 2011 to November 2012. Histological analysis of gonads showed that gametogenic activity of A. granosa occurred throughout the year, with maximum spawning activity observed from April 2012 to late June 2012 (15%–28%) in males and from March 2012 to late June 2012 (19%–44%) in females. Shell cross-section analysis showed that the increment widths of both sexes in the growing group (indeterminate and developing stages) and the spawning group (ripe and spawning stages) ranged from 35–57 to 8–17 µm, respectively. Seawater temperature and salinity recorded on a daily basis throughout the study period ranged from 22–33°C and 29–31, respectively. A comparison of increment width and gonad development stages in different environmental conditions showed that shell growth in the growing group decreased when seawater temperature and salinity decreased slightly. In contrast, increment widths in the spawning group were much narrower and were influenced by energy consumption during ripe and spawning stages. This study shows spawning breaks in shell structure are considered markers for identifying the period of sexual maturity. Therefore, spawning breaks are suitable proxies for interpretation of the temporal changes in shell microgrowth lines in terms of reproductive cycle of cockle and understanding the number of spawning periods throughout the year.

Love the one you’re with: genomic evidence of panmixia in the sablefish (Anoplopoma fimbria)

Understanding the genetic structure of a fishery may help delineate stocks and is directly applicable to resource management. To date, studies have not found clear population genetic structure across the range of the sablefish (Anoplopoma fimbria), yet significant biological differences are recognized. Here we use restriction site-associated DNA sequencing to develop thousands of single nucleotide polymorphisms (SNPs) throughout the sablefish genome and assess population genetic structure and examine the genome for SNPs under natural selection. Our study was unable to target spawning groups, having the potential to bias analyses that require a priori hypotheses of population structure. Low and insignificant levels of differentiation (FST= 0.0002) were observed among survey areas, and analyses of population structure suggested a single population. Only two SNPs were significantly associated with environmental variables. These results are likely due to considerable population mixing and suggest a single panmictic group of sablefish off the west coast of the United States and Alaska that is likely a consequence of a complex juvenile life history and long range movements as adults.

Fishery composition and evidence of population structure and hybridization in the Atlantic bonefish species complex (Albula spp.)

The distributions, genetic structure, and occurrence of hybrids were explored among three Atlantic bonefishes (Albula spp.), to determine recreational fishery composition, using 19 microsatellite loci. Between 1977 and 2012, study specimens were obtained from 14 locations across the Caribbean Sea and western Atlantic Ocean, with an external collection from the eastern Atlantic. The species were broadly sympatric across the region, though occurrence at the local level was variable, likely due to habitat partitioning. Albula vulpes appeared to be the primary contributor to the recreational fishery, which occurs predominantly in coastal flats habitats. Unexpected, non-geographic population partitioning was identified within all three species. Robust evidence for two genetic populations of A. vulpes was further supported by hypothesis testing for migration patterns between them. The potential existence of two quasi-discrete spawning groups (fall and spring) within species may explain the observed partitions. Patterns of interspecific hybridization were explored to further inform management and conservation efforts. Hybrids were observed at low frequency (40 individuals, equaling a 1.5 % hybridization rate), and most were collected from Florida and The Bahamas. Our results suggest that a combination of intrinsic and extrinsic semipermeable barriers to gene flow exists among these divergent species. These findings are congruent with previous studies that revealed substantial genetic divergence among these secondarily sympatric bonefishes. Further, clarification is provided on regional distributions and the composition of the economically and culturally important recreational fishery. On first order, management efforts would have the greatest impact if focused on A. vulpes populations and their preferred habitat.

Population structure and life history of Neomysis nigra Nakazawa, 1910 (Mysida) on Jeju Island, South Korea

Population structure and life history of the mysidNeomysis nigraNakazawa, 1910 were studied on Jeju Island, South Korea.N. nigrawas collected monthly from a shallow embayment of Jeju Island from May 2013 to May 2014. Temperature and salinity were measured during the sampling. The carapace length (CL) ofN. nigrawas measured. Life stages were divided into six categories and embryos in the marsupium were classified by developmental stages. During the study period, water temperatures ranged from −0.3 to 35.7°C. The CL of females was larger than that of males. The mean CL of adults was negatively correlated with water temperature. CL values in winter and spring were higher than those in summer and autumn. Brooding females and juveniles were found all year round. The abundance of juveniles was relatively higher in May, July, December, and February than in other months. The number of embryos in the marsupium increased with increasing female size. In conclusion, the present study suggests that the populations ofN. nigrahave four major spawning groups in a year and reproduce all year round.

Male pursuit of higher reproductive success drives female polyandry in the Omei treefrog

Female polyandry and corresponding multiple paternity have been detected in many species. Several hypotheses, such as the fertility guarantee hypothesis, the good gene hypothesis, the genetic compatibility hypothesis and the genetic diversity hypothesis, have been proposed to explain the evolution of female polyandry. Anuran amphibians are widely observed to breed in polyandrous spawning groups; however, few studies have evaluated multiple paternity in these species or the evolutionary mechanisms underlying polyandry. In this study, we addressed these questions pertaining to polyandry in the Omei treefrog, Rhacophorus omeimontis. Eight microsatellite markers of R. omeimontis were used to determine the patterns of paternity. Paternity analyses revealed that offspring were multiply sired in a majority (79.07%) of the polyandrous spawning groups. A male's reproductive output during a breeding season was greatly affected by the mating rate, revealing that male fitness benefited from multiple copulations. By contrast, no evidence supported the fertility guarantee hypothesis that polyandry increases the fertility rate of females or the compatible/good gene hypotheses that polyandrous females produce more compatible or superior offspring. The increased allelic diversity observed in polyandrous clutches is probably a nonadaptive by-product of multiple mating. In conclusion, males join as many copulations as possible to increase their reproductive success, regardless of whether their mate has already been in amplexus with other males. Females may gain no benefits from polyandry but are incapable of preventing superfluous males from joining the mating group due to the physical characteristics and breeding behaviour of anurans. Thus, in R. omeimontis, male pursuit of higher reproductive success is the primary explanation for female polyandry.

Asynchronous spawning in sympatric populations of a hard coral reveals cryptic species and ancient genetic lineages.

Genetic subdivision within a species is a vital component of the evolution of biodiversity. In some species of Acropora corals in Western Australia, conspecific individuals spawn in two seasons 6months apart, which has the potential to impede gene flow and result in genetic divergence. Genetic comparison of sympatric spring and autumn spawners of Acropora samoensis was conducted to assess the level of reproductive isolation and genetic divergence between the spawning groups based on multiple loci (13 microsatellite loci, the mitochondrial control region and two nuclear introns). Bayesian clustering and principal coordinate analysis of the microsatellite loci showed a high level of genetic differentiation between the spawning groups (F'ST =0.30; P<0.001), as did the sequence data from PaxC and Calmodulin (ΦST =0.97 and 0.31, respectively). At the PaxC locus, the autumn and spring spawners were associated with two divergent lineages that were separated by an evolutionary distance of 1.7% and statistical tests indicate divergent selection in PaxC, suggesting this gene may play a role in coral spawning. This study indicates that the autumn and spring spawners represent two cryptic species, and highlights the importance of asynchronous spawning as a mechanism influencing speciation in corals.

Modeled transport of winter flounder larvae spawned in coastal waters of the Gulf of Maine

AbstractWinter flounder, Pseudopleuronectes americanus, from southern New England and the Gulf of Maine were historically considered to be obligate estuarine spawners. However, recent experiments and observations document that winter flounder in the Gulf of Maine also utilize coastal waters for spawning. An individual‐based modeling approach was used to investigate the transport of winter flounder larvae from three hypothesized coastal spawning grounds in the Gulf of Maine. Transport success rates were greatest for larvae released from Ipswich Bay, intermediate for Stellwagen Bank and least successful for those released from Jeffreys Ledge. There was substantial interannual variability in larval transport and geographic patterns of potential connectivity. Furthermore, the date of spawning had an important influence on transport success. Model results suggest that certain coastal spawning grounds used by winter flounder may serve as an important source of larvae to estuaries and nearshore nursery areas. The potential influx of coastal spawned larvae could have implications for the resilience, productivity and gene flow in local populations. Model results provide further support for the conclusion that winter flounder in the Gulf of Maine may not be solely dependent upon estuaries for spawning. Results also suggest that coastal spawning groups should be considered explicitly in the management of winter flounder, and protected under Essential Fish Habitat regulations.

Population structure and variability of Pacific herring (Clupea pallasii) in the White Sea, Barents and Kara Seas revealed by microsatellite DNA analyses

Pacific herring, Clupea pallasii, have recently colonised the northeast Atlantic and Arctic Oceans in the early Holocene. In a relatively short evolutionary time, the herring formed a community with a complex population structure. Previous genetic studies based on morphological, allozyme and mitochondrial DNA data have supported the existence of two herring subspecies from the White Sea and eastern Barents and Kara Seas (C. p. marisalbi and C. p. suworowi, respectively). However, the population structure of the White Sea herring has long been debated and remains controversial. The analyses of morphological and allozyme data have previously identified local spawning groups of herring in the White Sea, whereas mtDNA markers have not revealed any differentiation. We conducted one of the first studies of microsatellite variation for the purpose of investigating the genetic structure and relationship of Pacific herring among ten localities in the White Sea, the Barents Sea and the Kara Sea. Using classical genetic variance-based methods (hierarchical AMOVA, overall and pairwise F ST comparisons), as well as the Bayesian clustering, we infer considerable genetic diversity and population structure in herring at ten microsatellite loci. Genetic differentiation was the most pronounced between the White Sea (C. p. marisalbi) versus the Barents and Kara seas (Chesha–Pechora herring, C. p. suworowi). While microsatellite variation in all C. pallasii was considerable, genetic diversity was significantly lower in C. p. suworowi, than in C. p. marisalbi. Also, tests of genetic differentiation were indicating significant differentiation within the White Sea herring between sympatric summer- and spring-spawning groups, in comparison with genetic homogeneity of the Chesha–Pechora herring.

Temporal Population Genetic Structure of Yellow Perch Spawning Groups in the Lower Great Lakes

AbstractThis study tested the hypothesis that the genetic composition of Yellow Perch Perca flavescens spawning groups at specific sites remained consistent among years or age‐cohorts; this likely would influence spatial population structure and be important for delineating management units. Previous studies identified that spawning groups genetically differed among locations across fine geographic scales, but it was unknown whether these patterns persisted from year to year. We analyzed 15 nuclear DNA microsatellite loci from Yellow Perch spawning at six Lake Erie locations in 2009 in reference to two out‐groups spawning in Lakes St. Clair and Ontario. Results were compared with a prior study of samples from the same locations that had been collected in various years, ranging from 2001 to 2005. We evaluated consistency for two of the spawning groups across multiple birth‐year‐cohorts. Results indicated that the levels of genetic diversity were similar across all spawning groups and years. All eight spawning groups genetically differed from one other, with their allelic compositions varying between the two sampling periods. Some variation occurred among individual sampling years and birth‐cohorts, with the 2003 cohort being the most distinctive. Sampling groups contained relatively high proportions of full siblings (mean = 18.5%, ranging to 75% for the 2001 birth‐cohort spawning at the eastern Lake Erie site), yet inbreeding appeared relatively low. Differences at sampling sites over time did not appear to reflect genetic drift but may instead suggest that spawning groups reproduce in slightly different locations from year to year or perhaps within a given season; this merits examination. Spatial and temporal patterns may reflect kin‐group structuring and differential reproductive success, in which strong year‐classes dominate spawning groups and impact genetic structure.Received October 28, 2013; accepted October 22, 2014

Isolated charrs of the genus Salvelinus (Salmonidae) from lakes of the Uzon Caldera, Kamchatka: 1. Charr of Lake Dal’nee

Charrs of the genus Salvelinus from the ultraoligotrophic Lake Dal’nee Maar differ from anadromous Dolly Varden S. malma in larger head with elongated jaws, larger gill cover, lower body with a deep caudal peduncle and short pelvic fins displaced anteriorly, larger number of scales in the lateral line, and larger number of rays in the unpaired fins. The lacustrine charrs also differ from the maternal Dolly Varden population in longer free part of the maxilla, lower widths of the opercular bones, and narrower suspensorium. Polymorphism of mtDNA is low, and unique haplotypes of the D-loop control region are not revealed. The life span of the lacustrine charrs reaches 11 years; and their maximum length and weight are 47 cm and 820 g. The spawning is registered in the fall at the slope of the bottom near the mouth of the single stream flowing into the lake. The abundance of the spawning group slightly exceeds 1000 individuals. This group is recruited from offspring migrating during their early life to the stream with limited food resources, and more numerous progeny remaining in the lake do not reach sexual maturity. The main food sources of adult charrs during summer are planktonic crustaceans, imago of insects, and own juveniles.

Gamete evolution and sperm numbers: sperm competition versus sperm limitation.

Both gamete competition and gamete limitation can generate anisogamy from ancestral isogamy, and both sperm competition (SC) and sperm limitation (SL) can increase sperm numbers. Here, we compare the marginal benefits due to these two components at any given population level of sperm production using the risk and intensity models in sperm economics. We show quite generally for the intensity model (where N males compete for each set of eggs) that however severe the degree of SL, if there is at least one competitor for fertilization (N - 1 ≥ 1), the marginal gains through SC exceed those for SL, provided that the relationship between the probability of fertilization (F) and increasing sperm numbers (x) is a concave function. In the risk model, as fertility F increases from 0 to 1.0, the threshold SC risk (the probability q that two males compete for fertilization) for SC to be the dominant force drops from 1.0 to 0. The gamete competition and gamete limitation theories for the evolution of anisogamy rely on very similar considerations: our results imply that gamete limitation could dominate only if ancestral reproduction took place in highly isolated, small spawning groups.

Consequences of a mismatch between biological and management units on our perception of Atlantic cod off New England

A mismatch between the scale of fishery management units and biological population structure can potentially result in a misperception of the productivity and sustainable yield of fish stocks. We used simulation modelling as a tool to compare the perception of productivity, stability, and sustainability of Atlantic cod (Gadus morhua) off New England from an operating model based on the current US management units to a model that more closely reflects the biological complexity of the resource. Two age-structured models were compared: (i) the management unit model, wherein cod were grouped based on the current spatially defined US management areas (Gulf of Maine and Georges Bank), and (ii) the biological unit model, consisting of three genetically defined population components (northern spring spawning, southern winter/spring spawning, and eastern Georges Bank spring-spawning groups). Overall, the regional productivity and maximum sustainable yield of the biological unit model was lower compared with the management unit model. The biological unit model also provided insights on the distribution of productivity in the region, with southern and northern spawning groups being the dominant contributors to the regional spawning–stock biomass and yield and the eastern Georges Bank spawning group being the minority contributor at low to intermediate levels of fishing mortality. The comparison of models revealed that the perception of Atlantic cod derived from the management unit model was of a resource that is more resilient to fishing mortality and not as susceptible to “collapse” as indicated by the biological unit model. For Atlantic cod, one of the main risks of ignoring population structure appears the potential for overexploitation of segments of the population. Consideration of population structure of cod changed our perception of the magnitude and distribution of productivity in the region, suggesting that expectations of sustainable yield of cod in US waters should be reconsidered.

Biochemical egg quality in a captive walleye (Sander vitreus) broodstock population relative to ovulation timing following hormonal treatment

The aim of this study was to evaluate how variations in total lipids, fatty acids, and total and free amino acids in eggs affect embryonic development throughout the spawning season in cultured walleye (Sander vitreus). Eggs were obtained from 4-year-old females and pooled based on spawning time: they were assigned to four consecutive periods during a one-month spawning season according to the first spawning occurrence in the female broodstock. Hatching success was significantly higher at the intermediate spawning period (87.3 ± 2.4%), and no eggs hatched in the late spawning group (p < 0.05). Egg diameter was significantly larger for the two intermediate spawning periods, which is related to the greater larval length at hatch during these two periods. Successful development was associated with the quality of lipid reserves throughout ontogeny. For polar fatty acids, there was a specific retention of essential fatty acids (EFA), particularly of the most abundant, i.e., docosahexaenoic acid (DHA), which made up more than 40% of the polar fatty acid fraction. For total amino acids, lysine (LYS) and serine (SER) levels were significantly higher in eggs from the intermediate spawning periods and were preferentially depleted during embryogenesis. During embryogenesis, energy was derived primarily from triacylglycerols (TAG), proteins, and non-essential free amino acids. Our results suggest that the content of EFA and amino acids in eggs may explain differences in egg quality and success of larval development within a broodstock population. Our results clearly show that the timing of ovulation during the spawning period affects the success of walleye aquaculture production.