Data/hora: 07/06/2024 03:25:38

Provedor de dados: 	5	
País: 	France	
Título: 	Influence of early thermic and photoperiodic control on growth and smoltification in Atlantic salmon (Salmo salar)	
Autores: 	Gaignon, Jean-louis; Quemener, Loic.	
Data: 	1992-07	
Ano: 	1992	
Palavras-chave: 	Photopériode; Température; Smolts 0+; Saumon atlantique; Photoperiod; Temperature; 0(+) smolts; Atlantic salmon.	
Resumo: 	Atlantic salmon juveniles were subjected to a precocious (day 104 after first feeding) photoperiodic (P) and thermic (T) control. After rearing the fry at 16 degrees C, constant (16 hours of light and 8 hours of darkness, 16 degrees C) (C) and shortened simulated natural S photoperiod and temperature regimes were used in a factorial experimental design until transfer to seawater. The growth obtained with constant (C) regimes was better than with S regimes. In all cases, we observed very early (day 141, mid-June) a clear segregation of the population into two different subpopulations. Among the conditions, all the differences between the upper and lower modes were growth-dependent. We observed different developmental trends of the gill (Na+-K+)-ATPase activity: the S regime gave a very progressive increase of the enzymatic activity, while we had a rapid decrease after a first phase of increase with a constant photoperiod. The absolute levels of the gill (Na+-K+)-ATPase activity were slightly lower than those observed in one year-old smolts. However, they arc quite similar to those of upper-mode fish that have a good salinity tolerance. After transfer to seawater, fish subjected to shortened simulated temperature and photoperiod had the lowest mortality and osmotic disturbance (after 48 hours and 3 weeks). Although the freshwater phase generally lasts more than 15-17 months for this species in a natural environment, we concluded that it is possible to obtain a good salinity tolerance after 7-8 months, with shortened simulated natural photoperiod and temperature regimes, in spite of the absence of a real smoltification; these regimes, however, must be applied during the "dynamic" presmolting phase when the growth is intense.	
Tipo: 	Text	
Idioma: 	Inglês	
Identificador: 	http://archimer.ifremer.fr/doc/00190/30159/28746.pdf

DOI:10.1051/alr:1992018	
Editor: 	Edp Sciences S A	
Relação: 	http://archimer.ifremer.fr/doc/00190/30159/	
Formato: 	application/pdf	
Fonte: 	Aquatic Living Resources (0990-7440) (Edp Sciences S A), 1992-07 , Vol. 5 , N. 3 , P. 185-195	
Fonte: 	IFREMER-Gauthier-Villars