Precocious Sexual Maturation in Atlantic Salmon (Salmo salar) Postsmolts Reared in a Seawater Impoundment

1978 ◽  
Vol 35 (9) ◽  
pp. 1269-1272 ◽  
Author(s):  
A. M. Sutterlin ◽  
P. Harmon ◽  
B. Young

Female Atlantic salmon, Salmo salar, usually become sexually mature following a minimum of one winter at sea. Between 4 and 16% maturation was observed for both sexes in two different stocks of salmon placed in sea water as 1+ yr smolts and subsequently reared one summer. Only the larger females and the smaller males matured. Egg size and fertility appeared normal. Smoltification at an early age or accelerated growth rates may be responsible for this phenomenon. Key words: Salinity tolerance, pen-rearing, brood stock, growth rates

2012 ◽  
Vol 69 (12) ◽  
pp. 1994-2006 ◽  
Author(s):  
Øystein Skaala ◽  
Kevin A. Glover ◽  
Bjørn T. Barlaup ◽  
Terje Svåsand ◽  
Francois Besnier ◽  
...  

Survival, growth, and diet were compared for farmed, hybrid, and wild Atlantic salmon (Salmo salar) families from the eyed egg to the smolt stage in River Guddalselva, Hardangerfjord, Norway. All individuals that survived until the smolt stage were captured in a Wolf trap and identified to one of the 69 experimental families using microsatellite markers. Survival of farmed salmon progeny was significantly lower than that of hybrids and wild progeny. However, survival varied considerably, from 0.17% to 6.4%, among farmed families. Egg size had an important influence on survival. Half-sib hybrid families with a farmed mother had higher survival when fathered by wild salmon than by farmed salmon. The overall relative survival of farmed families compared with that of their hybrid half-sib families fell from 0.86 in the second cohort to 0.62 in the last cohort with increasing fish density. Smolts of farmed parents showed significantly higher growth rates than wild and hybrid smolts. The overlap in diet among types of crosses demonstrates competition, and farm and hybrid progeny therefore will reduce the river’s capacity for production of wild salmon.


2006 ◽  
Vol 37 (13) ◽  
pp. 1348-1359 ◽  
Author(s):  
Navneet Gill ◽  
David A Higgs ◽  
Brent J Skura ◽  
Mahmoud Rowshandeli ◽  
Bakhshish S Dosanjh ◽  
...  

1985 ◽  
Vol 42 (3) ◽  
pp. 615-618 ◽  
Author(s):  
Richard L. Saunders ◽  
Charles B. Schom

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.


2012 ◽  
Vol 69 (11) ◽  
pp. 1817-1826 ◽  
Author(s):  
Bror Jonsson ◽  
Anders G. Finstad ◽  
Nina Jonsson

Field studies have revealed that many ectotherms mature younger and smaller in warmer environments although they grow faster. This has puzzled ecologists because the direct effect of factors that accelerate growth is expected to be larger, not smaller size. We tested this experimentally for Atlantic salmon (Salmo salar) at two winter temperatures and diets. Logistic regression revealed that the probability of maturation during the second year in sea water, relative to the probability of older maturation, increased with temperature and growth rate during the first winter. Also, large size and high condition factor 1 year prior to maturation stimulated maturation. In females, a high lipid diet increased the probability of maturation as one-sea-winter fish, and there were significant interactions between winter temperature and food quality and between body size and condition factor the first autumn in sea water. Thus, if the direct effect of temperature on growth rate is the main effect of warming, salmon are likely to attain maturity younger and smaller. Also, richer food decreased age at maturation in females. This finding has consequences for interpretations of climate change impacts on age at maturity in Atlantic salmon and may also hold for many other ectotherm species.


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