Energy allocation among developmental stages, age groups, and types of Atlantic salmon (Salmo salar) spawners

2003 ◽  
Vol 60 (5) ◽  
pp. 506-516 ◽  
Author(s):  
Nina Jonsson ◽  
Bror Jonsson

Relationships between energy density (kJ·100 g–1) and body length (mm), which varied between life-history stages of Atlantic salmon (Salmo salar), were described by power functions. The variation was chiefly caused by differences in lipid concentrations. Energy densities of maturing and rematuring parr were higher than those of similarly aged smolts. Monthly specific growth rate was higher in maturing parr than in salmon at sea. Mature parr males allocated relatively more energy to gonadal development and less to soma development than anadromous males. Spawning expenditure increased from 34 to 53% for 55- to 72-cm-long females. In males, similar losses were from 47 to 49% of their total energy content at river entry. More energy was used in reproduction in a long river than in a short one. Male allocation to gonads relative to soma was highest in the shorter river. Energy allocation pattern varied among developmental stages. Very energy-rich male parr rematured in subsequent years without going to sea; less energy-rich ones smolted and migrated to sea.

1981 ◽  
Vol 38 (4) ◽  
pp. 405-413 ◽  
Author(s):  
D. R. Idler ◽  
S. J. Hwang ◽  
L. W. Crim ◽  
D. Reddin

Radioimmunoassay (RIA) of plasma vitellogenin (Vg), estradiol (E2), 11-ketotestosterone (11-keto), and gonadotropin (GtH), together with histological techniques were evaluated for determination of the maturation stage of Atlantic salmon (Salmo salar) at sea.Male salmon had lower plasma Vg, E2, and higher 11-keto levels and could be distinguished from females several months in advance of spawning. Six female salmon were tagged at sea in 1975 in Placentia Bay and samples of blood taken. When the fish were recovered in rivers the lowest plasma Vg value was 396 μg/mL. This formed the basis of a working hypothesis, that fish with Vg values in excess of 396 μg/mL (~5–6 mo before spawning) will spawn in the year of capture. This hypothesis was supported by the Vg values of an additional 19 tagged females recaptured in Newfoundland and mainland rivers and brackish water off mainland rivers in 1976.Significant correlations between stage of gonadal development and plasma Vg, stage of gonadal development and gonadosomatic index (GSI), stage of gonadal development and plasma E2, plasma Vg and plasma E2, GSI and plasma E2, and between plasma Vg and 11-keto values were found for the female fish. The gonadal development of female fish from Bonavista Bay ranged between oil globule stage and secondary yolk stage. All those females which had reached the primary yolk stage would almost certainly mature and may be considered spawners of the year; on this basis 91% of the females were spawners of the year. Based on the minimum plasma Vg values, at sea, for fish which subsequently returned to the rivers, there were 86% spawners of the year among female salmon taken in Bonavista Bay. Based on plasma Vg levels, spawners of the year ranged from essentially zero in Greenland (fish captured in Greenland during August–November are not spawners of the year, except for the very few that spawn in one Greenland river) to 100% for fish caught in several other fisheries.11-Ketotestosterone was higher in the male fish than in the female fish and there was a correlation between GSI and 11-keto for male fish.The plasma GtH content of fish taken in the sea was extremely low as measured by RIA.Key words: salmon, maturation, migration, radioimmunoassay, vitellogenin, estradiol, gonadotropin, 11-ketotestosterone, histology, gonadosomatic index


2021 ◽  
pp. 381-389
Author(s):  
Larry Greenberg ◽  
Bror Jonsson ◽  
Johnny R. Norrgård ◽  
Ann Erlandsson ◽  
Eva Bergman

Temperature during egg incubation and early development influences later life stages of fishes, potentially influencing survival. Throughout its distribution, Atlantic salmon (Salmo salar Linnaeus, 1758) have experienced population declines, and in view of ongoing global warming, we tested if temperature during the earliest developmental stages modified body shape and fin size when temperatures averaged 2.6 vs. 5.6 °C. This temperature difference simulates increases predicted in climate change scenarios. Based on previous studies, we hypothesized that salmon originating from eggs subjected to cold incubation temperatures would have slimmer bodies and larger pectoral and dorsal fins than salmon from eggs that experienced warmer temperatures. After hatching, the juveniles were raised for 1 year under identical temperatures, after which we measured their body shape and fin areas. We found no support for our hypothesis regarding body shape. Indeed, we found the opposite, with cold-incubated salmon having deeper bodies than warm-incubated salmon. For fin size, the pectoral fins of cold-incubated salmon were larger than for warm-incubated salmon as predicted, but there was no difference in dorsal fin size. These results suggest that global warming may lead to altered body shape and fin size, possibly affecting swimming performance, and thus raise questions about the ecological consequences of the changes.


1983 ◽  
Vol 40 (1) ◽  
pp. 61-67 ◽  
Author(s):  
L. W. Crim ◽  
D. M. Evans ◽  
B. H. Vickery

Pellets designed for continuous, long-term, oligopeptide, hormone delivery were implanted into the adult landlocked Atlantic salmon (Salmo salar) to investigate the effects of LHRH agonist analogue (LHRH-A) upon the reproductive system. Chronic elevations in plasma gonadotropin were observed in experimental fish at a variety of stages of reproductive development. Synthesis of pituitary gonadotropin was also evoked in sexually regressed fish and fish undergoing gonadal recrudescence, but the already elevated level of pituitary GtH observed in prespawning and spawning salmon was not augmented. In prespawning fish, the events of ovulation and spermiation were accelerated by LHRH-A treatment. The LHRH-A hormone treatment also increased milt volume and the duration of spermiation in ripe males. In sexually regressed males LHRH-A treatment did not induce the advanced phases of spermatogenesis but some testicular stimulation was indicated by the presence of increased numbers of B-type spermatogonia and enlargement of the lumen of lobules. The gonadal response to LHRH-A treatment during the rapid phase of gonad recrudescence differed in males and females. Based upon the changes in GSI, the LHRH analogue accelerated vitellogenic development of the ovaries in females; in males, however, the GSI was significantly reduced following LHRH-A administration. Whereas, it seems clear that a long acting preparation containing LHRH-A can be successfully used in prespawning fishes to advance the final events of gonadal maturation and initiate spawning, further studies are necessary to evaluate the potential of LHRH agonists to either stimulate or inhibit the reproductive development of fish at other stages of the seasonal reproductive cycle.Key words: fish, teleosts, landlocked salmon, LHRH analogues, gonadotropic hormone releasing hormones, seasonal reproductive cycle, gonad development, spawning


2000 ◽  
Vol 57 (8) ◽  
pp. 1607-1616 ◽  
Author(s):  
Kevin G Whalen ◽  
Donna L Parrish ◽  
Martha E Mather ◽  
James R McMenemy

We used estimates of Atlantic salmon (Salmo salar) parr and smolt density, estimated in three tributaries of the West River, Vermont, U.S.A., to determine (i) if smolt recruitment is density dependent or independent of parr density, (ii) if the proportion of parr migrating as smolts and cohort survival differ among tributaries, and (iii) the effect of parr maturity on smolt production and recruitment variability. We found that parr to smolt recruitment was best described with a linear function providing no evidence for density dependence in the recruitment dynamics of parr and smolts at the tributary scale. The proportion of age-1 parr recruiting to age-2 smolts did not systematically differ among tributaries or years (overall mean ± 95% CL: 18 ± 11%, range = 9-37%), and mean age-1 to age-2 survival ranged less than twofold among tributaries (27-46%) and was independent of cohort density. Survival of age-1 mature (39%) and immature (33%) parr was similar, but probability of smolting for mature parr (0.21) was threefold less than for immature parr (0.76). Quantifying smolt recruitment pathways involving parr maturation helped elucidate the population-level effect of parr maturation on smolt production and recruitment variability.


2019 ◽  
Author(s):  
Teshome Tilahun Bizuayehu ◽  
Igor Babiak

Abstract Background The origin and contribution of seminal plasma RNAs into the whole semen RNA repertoire are poorly known, frequently being overlooked or neglected. Virtually nothing is known about seminal plasma RNAs in fish, including small RNAs, which have regulatory functions in gonadal development. Results In this study, we profiled microRNA (miRNA) constituents in the whole semen, as well as in fractionated spermatozoa and seminal plasma of Atlantic salmon (Salmo salar). Among 306 conserved miRNAs, 85 were differentially accumulated (>2 log-fold change and p-value < 0.01) between spermatozoa and the seminal plasma. We identified a number of seminal plasma-enriched and spermatozoa-enriched miRNAs. We localized the expression of some miRNAs in juvenile and mature testes. Two abundant miRNAs, miR-92a-3p and miR-202-5p, localized to both spermatogonia and somatic supporting cells in immature testis, and they were also highly abundant in somatic cells in mature testis. miR-15c-5p, miR-30d-5p, miR-93a-5p, and miR-730-5p were detected only in mature testis. miRs 92a-3p, 202-5p, 15c-5p, and 30d-5p were detected also in a juvenile ovary in locations corresponding to these from the testis. Additional RT-qPCR experiment demonstrated lack of correlation in miRNA transcript levels in seminal plasma versus blood plasma. Conclusions Our results indicate that salmon semen is rich in miRNAs, which are present in both spermatozoa and seminal plasma. The latter ones have partially different profile indicating their heterogenic origin. Testicular supporting somatic cells are likely the source of seminal plasma enrichment, whereas blood plasma unlikely contributes to the seminal plasma miRNA repertoire.


1989 ◽  
Vol 46 (10) ◽  
pp. 1726-1729 ◽  
Author(s):  
E. M. Williams ◽  
F. B. Eddy

Effects of nitrite on eggs, alevins, and fry of Atlantic salmon (Salmo salar) were studied and of these developmental stages eggs were the most resistant with a 24-h LC50 value of 3276 mg∙L−1 N∙NO2. Upon hatching tolerance sharply decreased, the 24-h LC50 value for early alevins (2940 mg∙L−1 N∙NO2) decreasing to 121.8 mg∙L−1 N∙NO2. Development in freshwater or dilute saline (10 mmol∙L−1 NaCl) proceeded normally without mortalities. Long-term exposure to nitrite concentrations as low as 14 mg∙L−1 N∙NO2 delayed hatching and retarded embryo growth and development as well as producing cardiovascular effects such as a reduced heart rate. The physiological and environmental implications of nitrite exposure are discussed.


1944 ◽  
Vol 22d (5) ◽  
pp. 105-125 ◽  
Author(s):  
Helen I. Battle

Series of eggs collected at various Canadian Atlantic Coast Hatcheries from 1934 to 1940 were used as the bases for a survey of the embryology of the Atlantic salmon (Salmo salar L.) from fertilization to hatching. Early developmental stages from cleavage to the delineation of the embryonic shield are described. Somite formation commences when the embryonic axis is between 1 and 2 mm. in length, and is complete shortly after closure of the blastopore when 60 somites are evident at an embryonic length of 6 mm. Following this the embryo takes on a progressively more fish-like form until hatching.The temperature of the water during most of the incubation period is relatively constant (0.5 °C. to 1 °C.) and the embryonic length data when plotted over this period fit the requirements for straight-line curves. The variation in the thermal units required to reach the same stage in different series indicates that their validity as criteria for determining comparable stages in embryonic development is doubtful.Periods of greatest mortality in development occur during cleavage and blastoderm formation to the closure of the blastopore and at hatching.


2015 ◽  
Vol 47 (12) ◽  
pp. 581-587 ◽  
Author(s):  
Krzysztof P. Lubieniecki ◽  
Natasha A. Botwright ◽  
Richard S. Taylor ◽  
Brad S. Evans ◽  
Mathew T. Cook ◽  
...  

We studied the expression of 28 genes that are involved in vertebrate sex-determination or sex-differentiation pathways, in male and female Atlantic salmon ( Salmo salar) in 11 stages of development from fertilization to after first feeding. Gene expression was measured in half-sibs that shared the same dam. The sire of family 1 was a sex-reversed female (i.e., genetically female but phenotypically male), and so the progeny of this family are all female. The sire of family 2 was a true male, and so the offspring were 50% male and 50% female. Gene expression levels were compared among three groups: 20 female offspring of the cross between a regular female and the sex-reversed female ( family 1, first group), ∼10 females from the cross between a regular female and a regular male ( family 2, second group) and ∼10 males from this same family ( family 2, third group). Statistically significant differences in expression levels between males and the two groups of females were observed for two genes, gsdf and amh/mis, in the last four developmental stages examined. SdY, the sex-determining gene in rainbow trout, appeared to be expressed in males from 58 days postfertilization (dpf). Starting at 83 dpf, ovarian aromatase, cyp19a, expression appeared to be greater in both groups of females compared with males, but this difference was not statistically significant. The time course of expression suggests that sdY may be involved in the upregulation of gsdf and amh/mis and the subsequent repression of cyp19a in males via the effect of amh/mis.


1979 ◽  
Vol 36 (5) ◽  
pp. 574-578 ◽  
Author(s):  
D. R. Idler ◽  
S. J. Hwang ◽  
L. W. Crim

An antibody prepared against salmon egg yolk proteins has been used to quantify Atlantic salmon (Salmo salar) plasma vitellogenin using radioimmunoassay. A low molecular weight fraction isolated from salmon egg yolk was used for radioiodination and as standard solution because plasma vitellogenin could not be iodinated successfully. Parallelism of the egg yolk standard to displacement given by a fraction isolated from vitellogenic salmon plasma and dilutions of plasma samples allowed the assay to be used to evaluate the state of gonadal development of migrating females several months in advance of spawning and for sexing relatively immature salmon. Key words: salmon, plasma vitellogenin; vitellogenin, quantification in salmon plasma; radioimmunoassay, salmon vitellogenin


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