Elects of Ozonated-Water Reuse on Salinity Tolerance of Atlantic Salmon

1990 ◽  
Vol 52 (1) ◽  
pp. 36-40 ◽  
Author(s):  
Hugh A. Poston ◽  
R. Conrad Williams
1981 ◽  
Vol 38 (10) ◽  
pp. 1189-1198 ◽  
Author(s):  
C. E. Johnston ◽  
R. L. Saunders

Six different rearing conditions were used to study the effect of temperature on seasonal changes in growth, condition factor, body silvering, body moisture and lipid content, salinity tolerance, and gill Na–K-ATPase activities of laboratory and pond-reared yearling Atlantic salmon (Salmo salar). Growth during the winter was greatest at the highest rearing temperature (16 °C) whereas those under simulated natural conditions grew slowest. Increasing temperatures in the spring stimulated growth more than constant temperature. Based on increased salinity tolerance, elevated ATPase activity, and growth in salt water, smolt development proceeded at all temperatures up to 16 °C. More smolts were produced in the high thermal regimes resulting in the best growth and the largest proportion of fish reaching smolt size. Unlike some Pacific salmonids, Atlantic salmon develop smolt status at temperatures as high as 16 °C. Yearling smolts can be produced at elevated temperatures and the use of thermal effluents for this purpose is promising.Key words: smoltification, smolt criteria, salinity tolerance, ATPase activity, rearing temperatures, elevated thermal regimes, thermal effluent, Salmo salar


1983 ◽  
Vol 61 (5) ◽  
pp. 1165-1170 ◽  
Author(s):  
S. E. Barbour ◽  
E. T. Garside

Parr of the diadromous and freshwater forms of the Atlantic salmon, Salmo salar L., were cultured through the smolt stage in photoperiod and temperature cycles that were delayed 3 months relative to those in nature. Such environmental manipulations caused a delay of approximately 3 months in smoltification of diadromous parr, as measured by changes in water and lipid content and salinity tolerance. These changes did not occur in parr of freshwater salmon exposed to the same modified photoperiod and temperature cycle. The implications of this are discussed.


2004 ◽  
Vol 32 (1) ◽  
pp. 225-243 ◽  
Author(s):  
Brian J. Vinci ◽  
Steven T. Summerfelt ◽  
Duncan A. Creaser ◽  
Ken Gillette

1987 ◽  
Vol 44 (8) ◽  
pp. 1462-1468 ◽  
Author(s):  
Stephen D. McCormick ◽  
Richard L. Saunders ◽  
Eugene B. Henderson ◽  
Paul R. Harmon

Atlantic salmon (Salmo salar) were subjected to artificial photoperiods to determine the manner and extent of photoperiod control of the parr–smolt transformation. Exposure to continuous light (L24) at first feeding and maintained throughout the rearing period inhibited increases in salinity tolerance and gill Na+,K+-ATPase activity that occurred in spring in fish raised under simulated natural photoperiod (SNP). Fish reared under continuous light and returned to SNP in October (L24OCT) underwent normal increases in salinity tolerance and gill Na+,K+-ATPase activity, whereas those returned in December (L24DEC) underwent delayed and intermediate increases. Plasma thyroxine peaks occurred simultaneously in all groups but were diminished in the L24 and L24DEC groups. Plasma 3,5,3′-triiodo-L-thyronine levels were not affected by any photoperiod treatment. Inhibition of the parr–smolt transformation decreased the potential for growth in seawater. In spite of changes in the timing of the transformation induced by photoperiod treatment, salinity tolerance and gill Na+,K+-ATPase activity were strongly correlated; correlation between changes in salinity tolerance and plasma thyroid hormones were, by comparison, weak. The results demonstrate that continuous light applied early in ontogeny and maintained throughout the rearing period inhibits osmoregulatory changes associated with parr–smolt transformation, whereas increasing day length during winter–spring stimulates transformation.


1995 ◽  
Vol 52 (2) ◽  
pp. 243-251 ◽  
Author(s):  
Åse I. Berge ◽  
Arne Berg ◽  
Trygg Barnung ◽  
Tom Hansen ◽  
Hans Jørgen Fyhn ◽  
...  

Groups of Atlantic salmon (Salmo salar), first fed in mid-February 1989, were reared under continuous light (LL) at 12–15 °C until late June. One group remained on LL, while the FEB, MAR, and MAY groups were subjected to segments of a simulated naturally increasing photoperiod (61°N), with initial daylength corresponding to February 1, March 15, and May 1, respectively. The MAR and FEB groups developed important smolt characters (increase in gill Na+,K+-ATPase activity, hypoosmoregulatory ability, and salinity tolerance) during the experiment whereas LL and MAY groups showed only incomplete changes in smolt status. The combination of continuous light during first feeding and early parr stages with a subsequent reduction to short daylength followed by a segment of simulated natural photoperiod allow important parts of the parr–smolt transformation to be completed. The period of exposure to short photoperiod is critical for the synchronization of smolt characters in underyearling Atlantic salmon.


1991 ◽  
Vol 69 (8) ◽  
pp. 2075-2084 ◽  
Author(s):  
Tim P. Birt ◽  
John M. Green ◽  
William S. Davidson

Parameters associated with the parr–smolt transformation were compared in cultured 1+ anadromous and nonanadromous Atlantic salmon derived from wild broodstock collected in Gambo River, Newfoundland. Progeny of nonanadromous salmon were significantly longer at swim-up than progeny of anadromous salmon, although consistent differences in growth performance were not observed during most of the 1 st year of development. Anadromous salmon grew more rapidly than nonanadromous salmon in the spring months during the smolting period. Distinct differences were noted between groups in seasonal levels of body silvering, gill Na+–K+ ATPase activity, and size and number of gill chloride cells. Most male nonanadromous salmon matured as "post-smolts," whereas maturation was not observed among female nonanadromous nor among either sex in the anadromous group. Differences between anadromous and nonanadromous salmon were not observed in seasonal levels of body moisture, plasma Na+ and Cl−, condition factor, or salinity tolerance. Differences noted between groups are probably genetic in nature and suggest that the two forms of salmon in Gambo River represent separate breeding populations.


1978 ◽  
Vol 35 (12) ◽  
pp. 1542-1546 ◽  
Author(s):  
Richard L. Saunders ◽  
Eugene B. Henderson

Gill Na+K+-activated ATPase activity increased during winter–spring in Atlantic salmon (Salmo salar) held at 10 °C and subjected to simulated natural or reciprocal (light/dark ratio opposite that of natural) photoperiods. ATPase activity increased earlier and was greater under the reciprocal than under the natural photoperiod regime. Body lipid decreased and moisture content increased sooner and more sharply in reciprocal than in natural photoperiod fish. Salinity tolerance (to 40‰) increased between March and April. Exposure to 40‰ salinity for periods up to 14 d gave marked increases in ATPase activity over levels measured in freshwater. Gill ATPase activity is a sensitive indicator of the ability of Atlantic salmon to osmoregulate in seawater. Together with lipid-moisture content, tolerance to high salinity, and migratory behavior, gill ATPase activity provides a valid indication of smolt readiness to migrate to sea. Key words: smolt criteria, photoperiod manipulation, Atlantic salmon, smolt physiology, salinity tolerance, osmoregulation


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