Plasma levels of five androgens and 17α-hydroxy-20β-dihydroprogesterone in immature and mature male Baltic salmon (Salmo salar) parr, and the effects of castration and androgen replacement in mature parr

1990 ◽  
Vol 68 (2) ◽  
pp. 263-267 ◽  
Author(s):  
Ian Mayer ◽  
Ingemar Berglund ◽  
Magnus Rydevik ◽  
Bertil Borg ◽  
Rüdiger Schulz
Keyword(s):  
Salmo Salar ◽  
Plasma Levels ◽  
High Plasma ◽  
Mature Male ◽  
Spawning Period ◽  
Immature Male ◽  
Mature Parr ◽  
Salmon Parr ◽  
Mature Male Parr

During the spawning period, the plasma levels of the androgens 11-ketotestosterone, testosterone, 11β-hydroxytestosterone, 11β-hydroxyandrostenedione, 11-ketoandrostenedione, and of the progestin 17α-hydroxy-20β-dihydroprogesterone were higher in mature compared with immature male Baltic salmon parr. 11-Ketotestosterone was always found to be the predominant androgen in the plasma of mature male parr and mature anadromous males. Mature male parr and large mature anadromous males had similar androgen profiles during the main spawning period, although 11-ketotestosterone tended to be higher in the mature anadromous males and testosterone was always higher in the mature male parr. At the time of the main spawning period, plasma levels of 17α-hydroxy-20β-dihydroprogesterone rose sharply in mature male parr, these levels being similar to those found in the plasma of large mature anadromous males. All measured androgens were low or nondetectable in castrated parr. Treatment of castrated parr with Silastic capsules containing 11-ketoandrostenedione resulted in high plasma 11-ketoandrostenedione levels and even higher levels of 11-ketotestosterone, indicating an extratesticular site of androgen conversion.

Seasonal endocrine changes in Baltic salmon, Salmo salar, immature parr and mature male parr. I. Plasma levels of five androgens, 17α-hydroxy-20β-dihydroprogesterone, and 17β-estradiol

1990 ◽  
Vol 68 (7) ◽  
pp. 1360-1365 ◽  
Author(s):  
Ian Mayer ◽  
Hans Lundqvist ◽  
Ingemar Berglund ◽  
Monika Schmitz ◽  
Rüdiger Schulz ◽  
...  
Keyword(s):  
Salmo Salar ◽  
Plasma Levels ◽  
Reproductive Season ◽  
Mature Male ◽  
Northern Sweden ◽  
17Β Estradiol ◽  
Mature Fish ◽  
High Level ◽  
Mature Male Parr ◽  
Immature Fish

Plasma levels of the androgens testosterone (T) and 11-ketotestosterone (OT), the progestin 17α-hydroxy-20β-dihydroprogesterone (17,20-P), and the estrogen 17β-estradiol (E2) were measured by radioimmunoassay in monthly samples from immature parr (mostly females) and mature male parr of Baltic salmon, Salmo salar. The parr belonged to the Umeälven stock, northern Sweden, and were kept at ambient photoperiod and temperature throughout their rearing period. The sampling began in February at the end of their 2nd year and continued until December. 11β-Hydroxytestosterone (OHT), 11β-hydroxyandrostenedione (OHA), and 11-ketoandrostenedione (OA) were measured at selected times only. The levels of OT, T, and 17,20-P were low in mature and immature fish from February until the summer; in the immature fish they remained low for the entire period. There were only minor differences in steroid levels between mature and immature fish before and during the first half of smoltification (May). This was also the case for OHT, OHA, and OA. In the mature fish, the levels of T and OT started to rise in June. T peaked in August–October, and OT in September–October. Both androgens dropped to a very low level in December. OT displayed the highest levels of all androgens in the reproductive season. 17,20-P rose to a high level in October, peaked in November, and was still high in December. E2 levels were relatively high in winter, declined during spring in both groups, and rose again in autumn. The poorer adaptability to seawater that has been observed in mature vs. immature fish could not be explained by differences in steroid levels at the time of smoltification.

Electrophoretic Assessment of the Contribution of Transplanted Scottish Atlantic Salmon (Salmo salar) to the Esva River (Northern Spain)

1994 ◽  
Vol 51 (2) ◽  
pp. 248-252 ◽  
Author(s):  
Paloma Morán ◽  
Alberto M. Pendás ◽  
Eva Garcia-Vázquez ◽  
Jorge T. Izquierdo ◽  
Dennis T. Rutherford
Keyword(s):  
Genetic Variation ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Gene Pool ◽  
Mature Male ◽  
Genetic Influence ◽  
Northern Spain ◽  
Atlantic Salmon Salmo Salar ◽  
Precocious Males ◽  
Mature Male Parr

The genetic influence of stocking on the Atlantic salmon (Salmo salar) population from the Spanish Esva River was analysed by electrophoresis of protein loci. Genetic variation within parr and mature male parr samples demonstrated that Scottish-origin parr stocked in 1990 survived the first summer. However, samples collected from returning adults in 1990 and 1991 did not indicate any contribution from previous stocking programs. Altered MEP-2* frequencies indicate that the native gene pool may have been disrupted by foreign genomes from precocious males or grilse.

Importance of the Variation in Life History Parameters of Atlantic Salmon (Salmo salar)

1985 ◽  
Vol 42 (3) ◽  
pp. 615-618 ◽  
Author(s):  
Richard L. Saunders ◽  
Charles B. Schom
Keyword(s):  
Life History ◽  
Atlantic Salmon ◽  
Population Size ◽  
Salmo Salar ◽  
Great Variability ◽  
Mature Male ◽  
Life History Parameters ◽  
Atlantic Salmon Salmo Salar ◽  
Sexually Mature ◽  
Mature Male Parr

Atlantic salmon (Salmo salar) demonstrate great variability in their life history; individuals from a given year-class can spawn during several years and can, therefore, breed with salmon from other year-classes. Atlantic salmon can mature after 1–4 sea-winters and some males mature as parr, during the second through fifth years, before going to sea. Salmon may survive to spawn more than once; some spawn several times. This variability in life history may be a safeguard against loss of small stocks through several successive years of reproductive failure, since nonspawning individuals in the river or at sea could spawn in subsequent years. Spawning populations are frequently quite small. The effective spawning population size may be potentially much larger, however, since members of several year-classes, including sexually mature male parr and anadromous adults of various ages, contribute to spawning. The level of inbreeding may be relatively low, since a number of year-classes, each with different sets of parents, are represented during spawning.

Behaviour of Mature Male Salmon Parr, Salmo salar juv L

Nature ◽  
1939 ◽  
Vol 143 (3613) ◽  
pp. 162-163 ◽  
Author(s):  
G. M. KING ◽  
J. W. JONES ◽  
J. H. ORTON
Keyword(s):  
Salmo Salar ◽  
Mature Male ◽  
Salmon Parr

The Effect of Impoundment on the Population and Movement of Atlantic Salmon in Ellerslie Brook, Prince Edward Island

1960 ◽  
Vol 17 (4) ◽  
pp. 453-473 ◽  
Author(s):  
J. W. Saunders
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Prince Edward Island ◽  
Salt Water ◽  
Mature Male ◽  
Freshwater Discharge ◽  
Age Group ◽  
Annual Variations ◽  
Sexually Mature ◽  
Mature Male Parr

During autumn spates Atlantic salmon (Salmo salar) commonly enter the small spring-fed streams of Prince Edward Island and spawn. Annual variations in freshwater discharge from Ellerslie Brook were found to determine the number of salmon and time of ascent. A pond formed on the brook created a habitat that exercised a strong retaining influence on the movements of spawners, kelts, parr, and migrating smolts. Smolts which stayed in the pond suffered heavy mortalities.Movements by sexually mature male parr, within and between fresh and salt water, occurred in the fall. Some parr remained in the estuary (0–27‰ salinity) throughout the year. The pond provided a habitat for parr.Smolt transformation at ages II and III occurred in the stream, pond, and estuary in the spring. Pond and stream smolts of the same age group were similar in size when they migrated.

Significance of Mature Male Parr in a Small Population of Atlantic Salmon (Salmo salar)

1989 ◽  
Vol 46 (6) ◽  
pp. 928-931 ◽  
Author(s):  
Jan Hennsng L'abée-Lund
Keyword(s):  
Atlantic Salmon ◽  
Population Size ◽  
Effective Population Size ◽  
Salmo Salar ◽  
Small Population ◽  
Mature Male ◽  
Effective Population ◽  
Atlantic Salmon Salmo Salar ◽  
Mature Male Parr

The spawning population of Atlantic salmon, Salmo salar, (mature male parr and adults (anadromous salmon)) were assessed in the River Baevra, central Norway, when the river was treated with rotenone in November 1986. The spawning population of adults consisted of 15 males and 19 females. The spawning population of males consisted of 167 mature male parr per adult male. The effective population size of adults was small; Na = 33.5 individuals. The presence of mature male parr theoretically increased the effective population size to Na = 71.7 individuals. This increase indicated that mature male parr brought the effective population size above a recommended minimum (Na = 50) to ensure long term viability.

Spawning behaviour and success of mature male Atlantic salmon (Salmo salar) parr of farmed and wild origin

2005 ◽  
Vol 62 (5) ◽  
pp. 1153-1160 ◽  
Author(s):  
Laura K Weir ◽  
Jeffrey A Hutchings ◽  
Ian A Fleming ◽  
Sigurd Einum
Keyword(s):  
Reproductive Success ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
First Generation ◽  
Large Male ◽  
Mature Male ◽  
Atlantic Salmon Salmo Salar ◽  
Spawning Behaviour ◽  
Mature Male Parr ◽  
Variance In Reproductive Success

We examined genetic differences in the reproduction of an alternative maturation phenotype in Atlantic salmon (Salmo salar) by comparing the spawning behaviour and success among farmed, first-generation hybrid, and wild mature male parr raised in similar environments. Parr competed for spawning opportunities in the presence of either wild or farmed large males. There were no consistent differences among groups in aggression; however, there were differences in spawning participation with respect to large male origin and among parr types. There was a strong negative temporal effect on mature male parr spawning participation that differed by parr type; wild and farmed parr were most likely to participate in early spawnings, with hybrids being the most likely to participate in late spawnings. Overall, parr were also less likely to participate in spawnings involving large farmed males. Variance in reproductive success was higher among parr than among large males. Our results are consistent with the hypothesis that there are genetically based behavioural differences among mature male parr of farmed and wild origin that may potentially lead to differences in reproductive success.

Seawater Adaptability in Baltic Salmon (Salmo salar): A Bimodal Smoltification Pattern in Previously Mature Males

1992 ◽  
Vol 49 (6) ◽  
pp. 1097-1106 ◽  
Author(s):  
Ingemar Berglund ◽  
Monika Schmitz ◽  
Hans Lundqvist
Keyword(s):  
Body Size ◽  
Salmo Salar ◽  
Mature Male ◽  
The Other ◽  
Seaward Migration ◽  
Previous Autumn ◽  
Mature Male Parr ◽  
Immature Fish

In three years, maximum seawater adaptability in 2-yr-old Baltic salmon (Salmo salar) was found during a period of about 2 wk in late May – early June. At this time the previously mature males developed in one of two directions. One group (8–44%) developed a seawater adaptability comparable with that of immature fish whereas the other did not. Previously mature males that did not adapt to seawater had larger gonadosomatic indices than males with good performance in seawater. Individually tagged previously mature males and immature fish released into the river in spring had a total adult recapture rate of 1.6 and 11.6%, respectively. In both groups the recapture rate was highest for fish released about 2 wk before the time of optimal seawater adaptability. The effect of size on recapture rate was more pronounced among previously mature males than among immature fish, with a particularly low recapture rate of small previously mature males. It is suggested that previously mature male parr can either mature sexually again or complete smoltification in spring and that the probability for smoltification and seaward migration is affected by body size and the conditions for growth during the previous autumn–winter.

Mating structure of an endangered population of wild Atlantic salmon (Salmo salar) as determined using sibship reconstruction and a novel method of sex inference

2012 ◽  
Vol 69 (8) ◽  
pp. 1352-1361 ◽  
Author(s):  
Louise G. de Mestral ◽  
Christophe M. Herbinger ◽  
Patrick T. O’Reilly
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Mature Male ◽  
Bay Of Fundy ◽  
Multilocus Genotype ◽  
Group Level ◽  
Atlantic Salmon Salmo Salar ◽  
Genotype Information ◽  
Novel Method ◽  
Mature Male Parr

The recent development of molecular genetic markers and methods of inferring relatedness among individuals using multilocus genotype information has allowed new insight into mating systems in the wild. Capitalising on the recently discovered linkage between the microsatellite locus Ssa202 and the sex-determining region of the Atlantic salmon Y chromosome, we developed a novel method to infer the sex of unsampled, wild-spawning parents of some of the few remaining wild, inner Bay of Fundy Atlantic salmon ( Salmo salar ). We inferred that most of the unsampled, reconstructed parents at the half-sib group level were likely polygamous females, while the parents at the full-sib group level (nested within half-sib groups) were likely monogamous males. Given the very low numbers of anadromous salmon returning to inner Bay of Fundy rivers to spawn, the putative male parents were likely mature male parr rather than anadromous males. This suggests that salmonid populations experiencing extreme declines may be composed of a high proportion of related individuals from relatively few sib groups and that mature male parr may provide an important genetic and demographic buffer to population decline.

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