Spawning Dates Research Articles

Spawning and Captive Propagation of Blackside Dace, Chrosomus cumberlandensis

Abstract Chrosomus cumberlandensis (Blackside Dace) is a federally protected stream fish endemic to the upper Cumberland River drainage of Kentucky and Tennessee. Captive propagation of the species has been conducted in only one previous study. Here we report new findings from spawning and rearing the species for the past three years, 2011–2013, at the Conservation Fisheries, Inc. (CFI) facility in Knoxville, TN. Brood stock (n = 80 adults) were collected in 2011–2012 from Big Lick Branch in Pulaski County, KY Spawning at the CFI facility occurred in April and May of each year when CFI water temperatures were between 16 and 21 °C. We compare CFI spawning dates and temperatures to those measured in a 2006 field study. We also provide video footage of spawning behavior, which conformed to that previously described in the literature. Per capita production of fry (i.e., number of juveniles reared per breeding adult) in 2012 was more than twice that achieved in the previous study. We progressively reduced the ...

Geographic variation in statolith trace elements of the Humboldt squid, Dosidicus gigas, in high seas of Eastern Pacific Ocean

We applied the solution-based inductively coupled plasma mass spectrometry to quantify trace elements in statoliths of Humboldt squid, Dosidicus gigas, collected from the high seas off Chile, Peru, and Costa Rica by Chinese squid jigging vessels during 2007–2009. All squid samples were aged and their spawning dates were back-calculated based on daily increments in statoliths. The most abundant trace elements in the whole statolith were Ca and Sr followed by other elements in the order of Fe, Mg, Zn, Ba, Cu, Mn, Ni, Al, Cr, Co, and U. Significant differences in Mn and Sr were found among samples from the three regions. Sr, Ni, Mn, and Co contributed significantly to the discrimination among the regions, with Co responsible for explaining most of the variation, followed by Ni, Mn, and Sr. Squid from the high seas off Costa Rica could be separated from those off Peru and Chile mostly due to the differences in Ni, Sr, and Co, while samples off Peru and Chile could be distinguished mainly because of differences in Mn and Co. Discriminant function analysis suggested that the overall cross-validated classification rate was 85.6 % with samples off Chile having the highest correct identification rates and samples off Costa Rica having the highest false classification rates. Significant positive relationships were found between sea surface temperature (SST) and Cr/Ca, Mn/Ca, and U/Ca, and there was a negative relationship between SST and Cu/Ca, Sr/Ca. This study suggests that the spatial difference in trace elements of statolith can be used to separate geographic populations of D. gigas and that elements having significant relationships with SST can be considered as natural indicators of ambient temperature.

Patterns of variability in early life traits of a Mediterranean coastal fish

Spawning dates and pelagic larval duration (PLD) are early life traits (ELT) crucial for understanding life cycles, properly assessing patterns of connectivity and gathering indications about patchiness or homogeneity of larval pools. Considering that little attention has been paid to spatial variability in these traits, we investigated variability of ELT from the analysis of otolith microstructure in the common two-banded sea bream Diplodus vulgaris. In the southwestern Adriatic Sea, along ~200 km of coast (~1° in latitude, 41.2° to 40.2°N), variability of ELT was assessed at multiple spatial scales. Overall, PLD (ranging from 25 to 61 d) and spawning dates (October 2009 to February 2010) showed significant variability at small scales (i.e. <6 km), but not at larger scales. These outcomes suggest patchiness of the larval pool at small spatial scales. Mul- tiple causal processes underlying the observed variability are discussed, along with the need to properly consider spatial variability in ELT, for example when delineating patterns of connectivity.

Spawning behaviour in Platygyra daedalea off South Africa

Coral spawning has never been observed in South Africa at the southernmost limit of scleractinian distribution along the East African Coast. Corals in the region are exposed to low temperatures (summer means of 26°C) and turbulent conditions (Schleyer et al. 2008), which may infl uence their spawning. Visiting the reefs at night is diffi cult, so 10 colonies of Platygyra daedalea (Ellis and Solander 1986) were collected on Two-mile Reef (27°31′376′′S, 32°41′181′′E) a few days before the Full Moon of February 2012 (07/02/12) and placed in open-water aquaria. The date of spawning in P. daedalea off South Africa was predicted from regular sampling of colonies from 2010. Spawning occurred over three consecutive nights (Full Moon +2 to +4 days) in 6-9 colonies at a water temperature of 26°C. The peak activity in spawning was observed at Full Moon +4days when 9 colonies spawn synchronously. Field sampling showed that in-situ colonies also spawned around these dates. Sperm and egg bundles were released between 19:00 to 22:00, with peak release at 20:30. Individual polyps released single bundles in synchronous waves, every 15-30 minutes. Each bundle of gametes was visible in the polyp mouth for 0.5-2 h before release (Figs 1A, B). During this time, they were rotated inside the polyp mouth, probably to compress the gametes and facilitate bundle expulsion (Fig. 1C). After release, the polyp mouth continued to gape for several minutes (Fig. 1D). This spawning behavior has been reported in several Platygyra species (Babcock et al. 1986). In the present study, the bundles averaged 2.2 mm (SE=0.2, N=25) in diameter and contained an average of 89.2 oocytes (SE=15.9, N=15). Each polyp released 2-3 bundles per spawning night. A single P. daedalea colony with an average diameter of 10 cm could thus re lease up to 10,000 oocytes per night. P. daedalea is known to spawn durSpawning behaviour in Platygyra daedalea off South Africa

Modeling the timing of spawning and hatching of shortnose sturgeon, Acipenser brevirostrum, in the Saint John River, New Brunswick, Canada

Timing of spawning and hatching of shortnose sturgeon, Acipenser brevirostrum , in the Saint John River, New Brunswick, Canada, was estimated using inverse prediction. We examined egg incubation periods at 5, 9, and 13 °C to back-calculate spawning dates. No larvae hatched at 5 °C. At 9 and 13 °C, hatching began after 18 and 8 days post fertilization, respectively. Lengths of yolk-sac larvae reared in the laboratory at 13–21 °C were used to develop a temperature-mediated Gompertz growth model. The inverted Gompertz model, predicting larval age from larval size and water temperature, was applied to 671, 164, and 746 larvae captured in the wild in 2008, 2009, and 2010, respectively. Estimated hatching distributions peaked in late May, and mean spawning events were predicted to occur in late April – early May (9 °C scenario) and middle to late May (13 °C scenario). Larval ages at the two sampling transects, 4.5 km apart, were similar, while catch per unit effort was lower downstream, indicating mortality during dispersal. Inverse prediction of larval ages provides fast and cost-effective estimates of the timing of spawning, hatching, and larval migration in the wild.

Is spawning time of marine fish imprinted in the genes? A two-generation experiment on local Atlantic cod (Gadus morhua L.) populations from different geographical regions

Abstract Otterå*, H., Agnalt, A-L., Thorsen, A., Kjesbu, O.S., Dahle, G., and Jørstad, K. 2012. Is spawning time of marine fish imprinted in the genes? A two-generation experiment on local Atlantic cod (Gadus morhua L.) populations from different geographical regions. – ICES Journal of Marine Science, 69: 1722–1728. Spawning time (onset of spawning) in Atlantic cod (Gadus morhua L.) was monitored in an experimental setup and combined with modelled spawning time estimates from the wild. The experiment broodstock were collected from several geographical areas and kept in a common environment. Their spawning times in 2004 were compared with the spawning times of their daughters in 2009 and 2010. Daughter spawning time was highly correlated with that of the mother, indicating genetic regulation of spawning time. However, large individual variation in spawning time was observed. The modelling data suggests a north-south gradient in onset of spawning along the Norwegian coast, driven by differences in temperature, i.e. later dates of spawning in the north.

Shifts in the timing of spawning in sole linked to warming sea temperatures

Phenotypic traits such as peak spawning time may vary within and differ between populations in relation to environmental factors, such as temperature. Sole (Solea solea) is a valuable, commercially exploited species that spawns in late winter or spring. The date of peak spawning was estimated for each year for seven stocks from monthly fish samples collected from commercial fisheries since 1970. Four out of seven stocks showed a significant long-term trend towards earlier spawning (Irish Sea, east-central North Sea, southern North Sea, eastern English Channel) at a rate of 1.5weeks per decade. The other three stocks (Bristol Channel, western English Channel and western-central North Sea) failed to show a relationship, but the available time series were limited for these stocks (<10years). Sea surface temperature during winter significantly affected the date of peak spawning, although the effect differed between stocks. The implications of the effect of winter temperature on the timing of spawning for the population dynamics are discussed.

Dead fish swimming: a review of research on the early migration and high premature mortality in adult Fraser River sockeye salmon Oncorhynchus nerka

Adult sockeye salmon Oncorhynchus nerka destined for the Fraser River, British Columbia are some of the most economically important populations but changes in the timing of their homeward migration have led to management challenges and conservation concerns. After a directed migration from the open ocean to the coast, this group historically would mill just off shore for 3-6 weeks prior to migrating up the Fraser River. This milling behaviour changed abruptly in 1995 and thereafter, decreasing to only a few days in some years (termed early migration), with dramatic consequences that have necessitated risk-averse management strategies. Early migrating fish consistently suffer extremely high mortality (exceeding 90% in some years) during freshwater migration and on spawning grounds prior to spawning. This synthesis examines multidisciplinary, collaborative research aimed at understanding what triggers early migration, why it results in high mortality, and how fisheries managers can utilize these scientific results. Tissue analyses from thousands of O. nerka captured along their migration trajectory from ocean to spawning grounds, including hundreds that were tracked with biotelemetry, have revealed that early migrants are more reproductively advanced and ill-prepared for osmoregulatory transition upon their entry into fresh water. Gene array profiles indicate that many early migrants are also immunocompromised and stressed, carrying a genomic profile consistent with a viral infection. The causes of these physiological changes are still under investigation. Early migration brings O. nerka into the river when it is 3-6° C warmer than historical norms, which for some late-run populations approaches or exceeds their critical maxima leading to the collapse of metabolic and cardiac scope, and mortality. As peak spawning dates have not changed, the surviving early migrants tend to mill in warm lakes near to spawning areas. These results in the accumulation of many more thermal units and longer exposures to freshwater diseases and parasites compared to fish that delay freshwater entry by milling in the cool ocean environment. Experiments have confirmed that thermally driven processes are a primary cause of mortality for early-entry migrants. The Fraser River late-run O. nerka early migration phenomenon illustrates the complex links that exist between salmonid physiology, behaviour and environment and the pivotal role that water temperature can have on population-specific migration survival.

Spatial variation in timing of marine subsidies influences riparian phenology through a plant-pollinator mutualism

Migratory animals are well-recognized for transporting energy and nutrients across habitat boundaries as resource subsidies but less is known about the secondary effects of these subsidies in supporting biodiversity in recipient ecosystems. In southwestern Alaska, fly-pollinated plants in the carrot family (Apiaceae) flower during the annual arrival of semelparous Pacific salmon to their natal streams to spawn. Blowflies (Calliphoridae) are an important consumer of salmon carcasses as larvae and pollinate Apiaceae as adults. Stable isotope analyses indicate that adult blowflies received the majority (85%) of their carbon and nitrogen from salmon carcasses and the remainder from riparian plants. A large terrestrial signature was passed maternally to blowfly eggs but quickly replaced by marine-derived resources as eggs developed into larvae on salmon carcasses. We also monitored the flowering phenology of kneeling Angelica (Angelica genuflexa) across salmon bearing streams (n = 20) that differ in the timing of salmon spawning. We found that salmon spawning date explained a substantial amount of the observed seasonal variation in peak flowering dates among streams and, when combined with longitude, explained 88% of the variation in seasonal phenology of Angelica among streams. By comparison, distance from the ocean, stream temperature, slope, aspect, and elevation in the riparian area had no relationship with Angelica bloom date. Together, these results suggest that spatial variation in salmon spawning timing is transmitted via the phenology of salmon-dependent consumers that affect the bloom timing of a common riparian plant.

The Effect of Stocking Densities on Reproductive Performance in Laboratory Zebrafish (Danio rerio)

Despite the growing popularity of the zebrafish model system, the optimal husbandry conditions for this animal are not well defined. The aim of this study was to examine the effect of stocking density on reproductive performance in zebrafish. In this study, undertaken by eight different zebrafish facilities, clutches of at least 200 wild-type zebrafish embryos from a single pairwise mating were produced at each participating institution and subsequently reared according to "in-house protocols" until they were 14 weeks old. Fish were then randomly assigned into treatment groups with balanced sex ratios and densities of 3, 6, or 12 fish/L. After a 1-month acclimation period, fish were spawned in pair crosses every 2 weeks for 3 months, for a total of six spawning dates. The number of viable and nonviable embryos produced in each clutch were counted at 1 day postfertilization. Although there was a great deal of variability in clutch size and percent spawning success among laboratories, there were no significant differences in average clutch size, spawning success, or percent viable among the treatment densities. These data suggest that using stocking densities as high as 12 fish/L does not have a negative impact on performance, when measured by reproductive performance.

The effect of water temperature on gamete maturation and gamete quality in the European grayling (Thymalus thymallus) based on experimental data and on data from wild populations

To investigate the effect of water temperature on gamete maturation and gamete quality, European grayling (Thymalus thymallus) were held under different temperature regimes prior to spawning. Maturation of males and females and their gamete quality depended strongly on temperature regime. The highest percentages of maturing fish and highest gamete quality were obtained under a creek water temperature regime with natural seasonal fluctuations. In warmed creek water (3-4°C), at a constant temperature of 8-9°C, and under an abruptly increasing temperature, regime maturation rates and gamete quality were reduced. The effect was more pronounced in females than in males. The spawning dates of different wild Austrian grayling populations were also correlated with water temperature data collected during the last 10-15 years. The mean spawning date expressed as the number of days from 21 December until spawning ranged from 98 to 111 days for lower elevation populations, while it was considerably delayed for an alpine population. All populations spawned at water temperatures of 5.5-7.2°C. Regression analysis indicated that spawning date correlated with (1) the overall mean water temperature from 21 December until spawning, (2) the mean water temperature during both the last 10 days and 15 days before spawning, and (3) the difference between mean January temperature and that of the last 15 days before spawning. The regression functions indicate that an increase in water temperature from 21 December to spawning of 1°C advances spawning by 5½ days, and an increase of 1°C in the last 10-15 days advances spawning by 3½ days.

Estimation of genetic parameters and breeding values in shrimp Fenneropenaeus chinensis using the REML/BLUP procedure

An analysis of a selection experiment was used to assess the impact of various animal model structures on REML estimates of variance components. The analyses were carried out based on 162 d body mass (BM) of 1 287 animals from 21 paternal half-sib groups of Fenneropenaeus chinensis. Estimated breeding values (EBV) of BM of all individuals were estimated using eight statistical models (A, AB, ABC, ABDC, ABMFC, ABMDC, ABFDC and ABMFDC) and BLUP (best linear unbiased prediction). These models were designed involving factors such as sex, spawn date as fixed effects, maternal genetic effects, full-sib family effects as random effects, mean BM of families at tagging and age at recording (covariate). The results demonstrate the importance of correct interpretation of effects in the data set, particularly those that can influence resemblance between relatives. The data structure and the particular model that was applied markedly influenced the magnitude of variance component estimates. Models based on few effects obtained upward biased estimates of additive genetic variance. The accuracy of genetic parameters and breeding value estimated by ABFDC model was higher than other models. The results imply that additive genetic direct value, full-sib family effects, and covariance effects besides sex and spawn date as fixed effects were very important for estimating genetic parameters and breeding value of body mass. This model had a heritability estimate of 162 d BM of 0.44. The comparison of the efficiency of selection based on breeding values or phenotypic value revealed great difference: average breeding value of the best 24 families selected by the 162 d BM breeding value and phenotype were 0.577 g and 0.366 g, respectively, representing a 36.57% higher efficiency in the former. In conclusion, selection based on breeding value was more effective than selection based on phenotypic value. Our results indicate that effects influencing the magnitude of estimates should be taken into account when estimating heritability and breeding values for BM.

Differences in spawning date between populations of common frog reveal local adaptation

Phenotypic differences between populations often correlate with climate variables, resulting from a combination of environment-induced plasticity and local adaptation. Species comprising populations that are genetically adapted to local climatic conditions should be more vulnerable to climate change than those comprising phenotypically plastic populations. Assessment of local adaptation generally requires logistically challenging experiments. Here, using a unique approach and a large dataset (>50,000 observations from across Britain), we compare the covariation in temperature and first spawning dates of the common frog (Rana temporaria) across space with that across time. We show that although all populations exhibit a plastic response to temperature, spawning earlier in warmer years, between-population differences in first spawning dates are dominated by local adaptation. Given climate change projections for Britain in 2050-2070, we project that for populations to remain as locally adapted as contemporary populations will require first spawning date to advance by approximately 21-39 days but that plasticity alone will only enable an advance of approximately 5-9 days. Populations may thus face a microevolutionary and gene flow challenge to advance first spawning date by a further approximately 16-30 days over the next 50 years.

Seasonal races of chum salmon Oncorhynchus keta and their interrelations in Kamchatka Rivers

Dates of migration and spawning, size-age structure, and fecundity of seasonal races of chum salmon Oncorhynchus keta from the Kol River are reviewed, those of early summer, late summer, and autumn races, as well as localization and structure of their spawning grounds, bed-sediment particle size in the redds, hydrological and thermal conditions on spawning grounds, and meristic characters of races. Special traits of reproduction of seasonal races within the species range and in Kamchatka in particular are discussed. The number of seasonal races in rivers depends on the presence of various habitats suitable for spawning. In rivers with complicated hydrogeomorphological structure, the number of seasonal races increases. Variations of types of seasonal races in a particular river and in the whole species area are epigenetic, i.e., they depend on the hereditary genetic program and presence of conditions providing its realization via various channels.

Modelling the transport of common sole larvae in the southern North Sea: Influence of hydrodynamics and larval vertical movements

In the present work we used a particle-tracking model coupled to a 3D hydrodynamic model to study the combined effect of hydrodynamic variability and active vertical movements on the transport of sole larvae in the southern North Sea. Larval transport from the 6 main spawning grounds was simulated during 40 day periods starting on 2 plausible spawning dates, the 15/04 and the 01/05, during 2 years, 1995 and 1996. In addition to a “passive” behaviour, 3 types of active vertical movements inspired from previous studies have been tested: (1) Eggs and early larvae float in the surface waters, late larvae migrate toward the bottom and stay there until the end of the simulation; (2 and 3) Eggs float in the surface waters, early larvae perform diel vertical migrations in the surface waters, and (2) Late larvae perform diel vertical migrations in the bottom waters until the end of the simulation; or (3) Late larvae perform tidally synchronised vertical migrations in the bottom waters until the end of the simulation. These behaviours have been implemented in the model with vertical migration rates, positive or negative, which can account for buoyancy or real swimming activity. Variations in larval transport were analysed in terms of mean trajectories, final larvae distribution, larval retention above nurseries, and connectivity. Results suggest that the variations in larval retention above nurseries due to the varying hydrodynamic conditions are not consistent in space i.e. not the same for all the spawning sites. The effect of active vertical movements on larval transport is also not consistent in space: Effects of active vertical movements include decreased retention above nurseries, decreased transport and/or decreased horizontal dispersion of larvae through reduced vertical shear (depending on the zone). The variability in larval retention due to hydrodynamic variability is higher than variability due to differences in the behaviour of larvae. In terms of connectivity, exchanges of larvae between the 6 areas considered are moderate: 10 connections happened out of the 30 possible, and the amount of larvae exchanged is much lower than the amount of larvae retained except in a few cases. This is not incompatible with the possible existence of subpopulations of sole in the Eastern Channel and southern North Sea.

10.1007/s11489-008-1005-4

For the first time, special traits of the reproduction of mykiss Parasalmo mykiss in Kamchatka are studied: dates of spawning, localization, topography and hydrology of spawning grounds, structure and fractional composition of ground of redds, duration of incubation and larval period, and thermal conditions. Possibilities of reproduction of mykiss are constrained by a narrow range of variation of spawning conditions. Spawning occurs only in tundra rivers and tributaries. The principal factor limiting reproduction of mykiss is temperature, namely a rapid warming of water in May and attaining of a necessary sum of degree-days (over 500, from the middle of May until the middle of July) during spawning and the period of incubation. Presence of water bodies of the tundra type with their special thermal conditions predetermine a possibility of reproduction of mykiss in Kamchatka and its present-day comparatively narrow area in Asia.

Testing the synergistic effects of GnRH and testosterone on the reproductive physiology of pre‐adult pink salmonOncorhynchus gorbuscha

To test the hypothesis that the hypothalmic gonadotropin-releasing hormone (GnRH) and testosterone (T) co-treatment stimulates both the hypothalmo-pituitary-gonadal (HPG) and hypothalmo-pituitary-interrenal axes, the reproductive and osmoregulatory responses of pre-adult pink salmon Oncorhynchus gorbuscha were compared after GnRH and T administration either alone or in combination. Relative to controls, neither GnRH nor T treatment resulted in significantly greater ovarian or testicular growth, but co-treatment significantly increased ovarian growth after 5 months. Interestingly, the stimulation was undetectable after 3 months. However, once daily photoperiod began shortening after the summer solstice, c. 2 months before the natural spawning date, GnRH+T-treated females were stimulated to produce larger ovaries. Final fish body length and the size of individual eggs did not differ among treatment groups. GnRH+T eggs, however, showed signs of advanced vitellogenesis relative to GnRH-treated and control eggs, whereas T-treated eggs became atretic. Testis size increased significantly from initial values and most males were spermiating, but this growth and development were independent of hormone treatments. Final plasma ion, metabolite and cortisol concentrations did not differ among treatment groups. It is concluded that GnRH+T co-treatment was effective in stimulating female but not male maturation. GnRH and T treatment, however, presumably had little effect on the hypothalmo-pituitary-interrenal axis as observed by ionoregulatory status.

Use of Carcass Recovery Data in Evaluating the Spawning Distribution and Timing of Spring Chinook Salmon in the Chiwawa River, Washington

AbstractSpawning ground surveys are routinely conducted to assess status and trends for many populations of Pacific salmon Oncorhynchus spp. Biological data from carcasses recovered during spawning ground surveys are used for various stock assessment purposes but may also be useful in comparing the spawning distribution and timing of hatchery‐ and naturally produced fish. The objective of this study was to measure the distance between redd and carcass locations of spring Chinook salmon O. tshawytscha in the Chiwawa River and assess whether carcass location adequately represents spawning location. We also estimated the redd residence time (d) of hatchery‐ and naturally produced spring Chinook and compared the spawn timing using both redd and carcass data for hatchery‐ and natural‐origin fish. We determined the redd location, spawn timing, and carcass location of individual hatchery‐ and naturally produced spring Chinook salmon during spawning ground surveys using passive integrated transponder tags implanted during the adults' migration to the spawning grounds. Differences in mean carcass drift (the distance between redd location and carcass location) were detected between male (4,465 m) and female (150 m) spring Chinook salmon (P &lt; 0.003) but not between hatchery‐ and naturally produced females (P = 0.32). The mean spawn date and the estimated spawn date derived from carcasses were not significantly different for either hatchery‐ or natural‐origin spring Chinook salmon (P &gt; 0.05). We concluded that the use of carcass data from female spring Chinook salmon to estimate the spawning location and timing is appropriate when surveys are conducted on a consistent weekly schedule throughout the entire spawning period.

Identification, development, and characterization of three molecular markers associated to spawning date in Coho salmon ( Oncorhynchus kisutch)

In salmonids, spawning date is an important productive and life-history trait determining the time of fertilization, date of progeny emergence, and even the probability of survival and the growth rate of the small fry. Recent evidences support a polygenic basis with several Quantitative Trait Loci (QTL) affecting the phenotypic expression of this trait in salmon species. Utilizing females from two populations of Coho salmon ( Oncorhynchus kisutch) obtained by divergent selection for early and late spawning date, we have identified three RAPD markers amplified with primers UBC-075, UBC-229 and UBC-249 associated with spawning date. Polymorphic fragments were characterized and converted in two codominant and one dominant SCAR PCR-based marker Oki075 ( AY926350), OkiCAT229UCH ( AY926352) and Oki249 ( AY929856). The SCARs Oki075 and Oki249 have been mapped at different chromosomes using FISH. We identified a 52 bp repetitive motif minisatellite like on marker Oki075 and a microsatellite di-nucleotide TG/AC motif on marker OkiCAT229UCH. These three SCAR markers show significant association with spawning date in Coho salmon, however it was not possible to discard a genetic drift effect, therefore more study is necessary to verify the associations presented here.

Population structure of the masu salmon Oncorhynchus masou from the Kol River (Western Kamchatka) and geographic variation in the species area

According to materials from original investigations in Kamchatka as well as published data, the population structure and geographical variation of the masu salmon Oncorhynchus masou are considered in the species area. The intraspecies structure, dates of their run to rivers, dates of spawning, traits of spawning, size-age and sex composition, fecundity, biological traits of parr, downstream migration of smolts are investigated. The relationship is shown between the manifestations of geographical variation of masu salmon and the factor of temperature. It is assumed that the global warming of climate would contribute to the advancement of this species to northern areas and to the increase in its abundance.