The parr–smolt transformation of Arctic charr is comparable to that of Atlantic salmon

Jørgensen, Even H.; Aas-Hansen, Øyvind; Moriyama, Shunsuke; Iwata, Munehico; Strand, Jo Espen Tau

doi:10.1016/j.aquaculture.2007.10.004

Cited by 14 publications

(12 citation statements)

References 39 publications

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“…The high survival and growth in the groups exposed to the greatest direct increases in salinity (F25 and F29) may to some extent be attributed to the pre‐experimental rearing in salinity 3·7 and continuous light (24L:0D). In this environment, the juveniles appear to have developed good SW tolerance, as they had similar gill NKA activity as previously reported for S. alpinus smolts (Eliassen et al , ; Staurnes & Finstad, ; Jørgensen et al , ), and about two times higher NKA activity compared with 296 g S. alpinus of the same strain kept in FW under continuous light (Gunnarsson, ). It also appears that the juveniles were not fully adapted to SW, as growth rates in the F25 and F29 groups were depressed for the first 3 months of the trial, whereas 150 g S. alpinus of the Norwegian Hammerfest strain can be directly transferred from FW to SW under natural photoperiod in April without showing significant reduction in growth over a period of 30 days (Arnesen et al , 1993 b ).…”

Section: Discussionsupporting

confidence: 80%

“…In anadromous salmonids, this physiological pre‐adaptation to SW is an important component of a series of physiological, morphological and behavioural changes collectively known as parr‐smolt transformation or smoltification (Hoar, ), and is under complex endocrine control (Björnsson et al , ). The timing of the development of hypo‐osmoregulatory capacity in S. alpinus as for other smoltifying salmonids is driven primarily by the seasonal increase in day length during spring (Finstad et al , 1989 a ; Arnesen et al , ; Jørgensen et al , ). The increased SW tolerance of salmonid smolts is usually reflected in increased Na + , K + ‐ATPase (NKA) activity in ionocytes in the gill (McCormick, ), and such increases in NKA have also been documented for S. alpinus (Damsgård, ; Arnesen et al , ).…”

Section: Introductionmentioning

confidence: 99%

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Long‐term rearing of Arctic charr Salvelinus alpinus under different salinity regimes at constant temperature

Árnason

Gunnarsson

Imsland

et al. 2014

Journal of Fish Biology

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Arctic charr Salvelinus alpinus of the Hólar strain (mean ± s.e. body mass = 152·1 ± 3·1 g) were reared at four different salinity regimes at a constant temperature of 7·4° C. Two groups were given a three-month acclimation in salinity 18 before the salinity was increased to either 25 or 29 (groups called A25 and A29), and two groups were reared in salinities 25 or 29 over the full experimental period of 409 days (groups called F25 and F29). In the first 3 months, the A25 and A29 groups had the highest growth rates. By October 2011, there were no significant differences (two-way nested ANOVA, P > 0·05) in the mean body masses among A25, F25 and F29 (c. 1450 g), whereas A29 had a lower mean mass (1282 g). The growth in the last period from October 2011 to January 2012 was reduced by sexual maturation in the highest salinity regimes (A29 and F29), whereas fish in groups A25 and F25 showed high growth throughout the study. Males in all salinity groups had higher growth rates than females for the most part of the study, but the divergence between the sexes was most pronounced in the highest salinity regimes. All salinity groups showed distinct changes in Na(+) , K(+) -ATPase activity, with high activity in spring and summer, and lower activity in the autumn. Plasma sodium (Na(+) ) levels were stable indicating that none of the experimental groups had problems in maintaining hydromineral balance during the study. While plasma leptin levels were not affected by salinity regimes, it was noted that these levels were 13-30% higher in fish with empty guts compared with those having food in their gut at the time of sampling. This suggests a link between leptin levels and food intake, indicating that this hormone may play a role in food intake and energy allocation in fishes.

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Section: Discussionsupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Long‐term rearing of Arctic charr Salvelinus alpinus under different salinity regimes at constant temperature

Árnason

Gunnarsson

Imsland

et al. 2014

Journal of Fish Biology

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“…It has been suggested that the smoltification process of S . alpinus is similar to that of the Atlantic salmon Salmo salar L. 1758 (Aas‐Hansen et al , ; Jørgensen et al , ) with significant increase in the gill Na + , K + ‐ATPase (NKA) activity and improved hypo‐osmoregulatory ability. The smoltification process in S .…”

Section: Introductionmentioning

confidence: 54%

Effects of short‐day treatment on long‐term growth performance and maturation of farmed Arctic charr Salvelinus alpinus reared in brackish water

Gunnarsson

Johansson

Gústavsson

et al. 2014

Journal of Fish Biology

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The effects of a 6 week short-day photoperiod followed by continuous light, applied during the juvenile phase of Arctic charr Salvelinus alpinus in fresh water on smoltification and on the long-term growth and maturity following transfer to brackish water (BW) (constant salinity of either 17 and 27 or increasing salinity in steps from 17 to 27) were investigated. Prior to salinity transfer, the juveniles were either reared at continuous light (C group) or reared for 6 weeks on a short day (8L:16D, S group) followed by continuous light (24L:0D). Increased salinity had negative effect on growth, with female fish reared at 17 salinity weighing 19 and 27% more than the salinity-step group (17-27) and the 27 salinity group, respectively. The stepwise acclimation to salinity had limited advantage in terms of growth rate. Short photoperiod for 6 weeks (November to January) followed by continuous light improved growth, but not seawater (SW) tolerance. Gill Na(+) , K(+) -ATPase activity and plasma Na(+) levels changed with time, indicating some variation in osmoregulatory capacity during the experimental period. Overall, there appear to be interactive effects on maturation from applying short-day photoperiod followed by rearing at higher salinities. Plasma leptin varied with time and may be linked to stress caused by the observed variations in osmoregulatory ability. It is concluded that changes in growth rates observed in this study are mainly related to rearing salinity with higher growth rates at lower salinities. Short-day photoperiod has some growth-inducing effects but did not improve SW tolerance. Farmers of S. alpinus using BW for land-based rearing should keep salinity at moderate and stable levels according to these results to obtain best growth.

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“…Species-specific osmoregulatory response of IGF-I mRNA expression is well-known (McCormick 2001;Mancera and McCormick 2007). For example, in salmonids, parr-smolt transformation is associated with IGF-I mRNA increase (McCormick 2001;Reinecke et al 2005;Jørgensen et al 2007). Also, the transference of the black-chinned tilapia O. melanotheron heudelotii to seawater then to freshwater resulted in a transient IGF-I mRNA down-regulation (Link et al 2010).…”

Section: Gh/igf-i Axismentioning

confidence: 96%

Acclimation to different environmental salinities induces molecular endocrine changes in the GH/IGF-I axis of juvenile gilthead sea bream (Sparus aurata L.)

2014

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To assess the role of the GH/IGF-I axis in osmotic acclimation of the gilthead seabream Sparus aurata, juvenile specimens were acclimated to four environmental salinities: hyposmotic (5 ‰), isosmotic (12 ‰) and hyperosmotic (40 and 55 ‰). The full-length cDNAs for both pituitary adenylate cyclase-activating peptide (PACAP) and prepro-somatostatin-I (PSS-I), the precursor for mature somatostatin-I (SS-I), were cloned. Hypothalamic PACAP and PSS-I, hypophyseal growth hormone (GH) and prolactin (PRL), and hepatic insulin-like growth factor-I (IGF-I) mRNA expression levels were analyzed in the four rearing salinities tested. PACAP and IGF-I mRNA values increased significantly in response to both 5 and 55 ‰ salinities, showing a U-shaped curve relationship with the basal level in the 40 ‰ group. Hypothalamic PSS-I expression increased strongly in the 55 ‰ environment. GH mRNA levels did not change in any of the tested environmental salinities. PRL mRNA maximum levels were encountered in the 5 and 12 ‰ environments, but significantly down-regulated in the 40 ‰. Plasma cortisol levels significantly increased in the 40 ‰ environment. These results are discussed in relation to the well-known high adaptability of Sparus aurata to different environmental salinities and the role of the GH/IGF-I axis in this process.

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The parr–smolt transformation of Arctic charr is comparable to that of Atlantic salmon

Cited by 14 publications

References 39 publications

Long‐term rearing of Arctic charr Salvelinus alpinus under different salinity regimes at constant temperature

Long‐term rearing of Arctic charr Salvelinus alpinus under different salinity regimes at constant temperature

Effects of short‐day treatment on long‐term growth performance and maturation of farmed Arctic charr Salvelinus alpinus reared in brackish water

Acclimation to different environmental salinities induces molecular endocrine changes in the GH/IGF-I axis of juvenile gilthead sea bream (Sparus aurata L.)

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