Determination of Sexual Maturation Stages of Atlantic Salmon (Salmo salar) Captured at Sea

1981 ◽  
Vol 38 (4) ◽  
pp. 405-413 ◽  
Author(s):  
D. R. Idler ◽  
S. J. Hwang ◽  
L. W. Crim ◽  
D. Reddin
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Gonadosomatic Index ◽  
Gonadal Development ◽  
Maturation Stage ◽  
Female Fish ◽  
Histological Techniques ◽  
Atlantic Salmon Salmo Salar ◽  
Placentia Bay

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

Role of Fat Stores in the Maturation of Male Atlantic Salmon (Salmo salar) Parr

1991 ◽  
Vol 48 (3) ◽  
pp. 405-413 ◽  
Author(s):  
D. K. Rowe ◽  
J. E. Thorpe ◽  
A. M. Shanks
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Gonadosomatic Index ◽  
Total Lipids ◽  
Fat Accumulation ◽  
Atlantic Salmon Salmo Salar ◽  
Mesenteric Fat ◽  
Fat Stores

We provide evidence that in male Atlantic salmon (Salmo salar) parr, maturation is suppressed when mesenteric fat fails to exceed an undefined level by May. In nonmaturing parr the postwinter increase in total lipids began in May, while the mesenteric store started filling in June. However, in male parr which would have matured, total lipids started increasing a month earlier, in April, and the mesenteric store started filling in May. Consequently, maturing male parr had significantly more mesenteric fat than nonmaturing fish by June. Mesenteric fat is needed for maturation. Levels continued to increase in nonmaturing parr during autumn months, but had declined in maturing parr by September. This depletion of mesenteric fat in maturing males coincided with increases in the gonadosomatic index from 0.05 to 10% and with reductions in both feeding and growth. Fasting during spring months delayed increases in total lipids and fat accumulation into the mesenteric store until June and suppressed maturation rates of male parr. The internal decision to suppress maturation is therefore dependent on mesenteric fat levels increasing in May. However, this requires the prior replenishment of other stores in April. A model is proposed to explain the physiological link between fat accumulation during spring and the initiation of maturation.

Manipulation of the Seasonal Reproductive Cycle of the Landlocked Atlantic Salmon (Salmo salar) by LHRH Analogues Administered at Various Stages of Gonadal Development

1983 ◽  
Vol 40 (1) ◽  
pp. 61-67 ◽  
Author(s):  
L. W. Crim ◽  
D. M. Evans ◽  
B. H. Vickery
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Reproductive Cycle ◽  
Gonad Development ◽  
Reproductive Development ◽  
Hormone Treatment ◽  
Gonadal Development ◽  
Rapid Phase ◽  
Atlantic Salmon Salmo Salar ◽  
Lhrh Analogues

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

scholarly journals Heterogenic origin of micro RNAs in Atlantic salmon (Salmo salar) seminal plasma

2019 ◽  
Author(s):  
Teshome Tilahun Bizuayehu ◽  
Igor Babiak
Keyword(s):  
Atlantic Salmon ◽  
Blood Plasma ◽  
Salmo Salar ◽  
Seminal Plasma ◽  
Somatic Cells ◽  
Gonadal Development ◽  
P Value ◽  
Atlantic Salmon Salmo Salar ◽  
Micro Rnas ◽  
Regulatory Functions

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.

In vivo determination of fat content in Atlantic salmon (Salmo salar) with a mobile NMR spectrometer

2005 ◽  
Vol 85 (8) ◽  
pp. 1299-1304 ◽  
Author(s):  
Emil Veliyulin ◽  
Claas van der Zwaag ◽  
Wolfgang Burk ◽  
Ulf Erikson
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Fat Content ◽  
Atlantic Salmon Salmo Salar ◽  
Mobile Nmr

scholarly journals Regional mtDNA SNP differentiation in European Atlantic salmon (Salmo salar): an assessment of potential utility for determination of natal origin

2012 ◽  
Vol 69 (9) ◽  
pp. 1625-1636 ◽  
Author(s):  
Eric Verspoor ◽  
Sonia Consuegra ◽  
Olafur Fridjonsson ◽  
Sigridur Hjorleifsdottir ◽  
David Knox ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Microsatellite Locus ◽  
Resolving Power ◽  
Restriction Enzyme Digestion ◽  
Potential Utility ◽  
Natal Origin ◽  
Atlantic Salmon Salmo Salar ◽  
Mtdna Snp

Abstract Verspoor, E., Consuegra, S., Fridjonsson, O., Hjorleifsdottir, S., Knox, D., Olafsson, K., Tompsett, S., Wennevik, V., and Garciá de Leániz, C. 2012. Regional mtDNA SNP differentiation in European Atlantic salmon (Salmo salar): an assessment of potential utility for determination of natal origin. – ICES Journal of Marine Science, 69: 1625–1636. The Atlantic salmon, Salmo salar, shows geographically structured differentiation at various classes of molecular genetic variation, among and within river stocks. Nuclear microsatellite locus variation at multiple loci has been exploited for more than a decade as a marker for the continental origin of fish caught at sea in distant-water fisheries. However, a simpler, more cost-effective, but still accurate, assignment can be obtained using a single microsatellite locus in combination with a mitochondrial DNA (mtDNA) single-nucleotide polymorphism (SNP) detected by restriction enzyme digestion. Following on from this, a preliminary study was made of the potential for using mtDNA SNP variation to enhance the resolving power and cost-effectiveness of within-continent assignment of European salmon as determined using microsatellites. Variation in 20 mtDNA regions, encompassing ∼43% of this genome, in 330 salmon from 29 rivers across Europe, was analysed. High levels of inter-individual and inter-river variation were found, as well as evidence of regional differentiation paralleling observed microsatellite differentiation. The observations indicate scope for using mtDNA SNPs along with microsatellites for genetically based assignment of European salmon to region and river of natal origin, but further study is needed.

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
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Developmental Stages ◽  
Energy Content ◽  
Energy Allocation ◽  
Gonadal Development ◽  
Power Functions ◽  
Allocation Pattern ◽  
Atlantic Salmon Salmo Salar ◽  
Mature Parr

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.

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