Condition and performance of juvenile Atlantic salmon (Salmo salar): effects of rearing practices on hatchery fish and comparison with wild fish

Abstract

This study examined the effects of various modifications of rearing practices on hatchery-reared Atlantic salmon (Salmo salar) fingerlings and compared condition and performance of hatchery fingerlings (age 0+) and yearlings (age 1+) with those of wild-reared Atlantic salmon. Reduced fish density (and increased ration) in rearing tanks promoted increased growth and condition factor and significant changes in muscle composition, including increased muscle lipid content and glycolytic enzyme activity, specfically phosphofructokinase and lactate dehydrogenase. However, these changes had no effect on anaerobic capacity. Moreover, swimming performance was poorer in fingerlings reared at low compared with normal density. Raising the water velocity from 0 to 4 cm ·s-1 (~0.7 body length ·s-1) had overall beneficial effects, most notably increased endurance in fixed velocity sprint tests and a reduction of ion loss in an epinephrine challenge test. Increasing velocity to 9 cm ·s-1 had no further effects. Wild fingerlings were larger with better fin quality and superior anaerobic capacity and swim performance. Even larger differences were seen between hatchery-reared and wild yearlings. It is concluded that significant changes in morphology, physiology, and muscle biochemistry of juvenile Atlantic salmon can be brought about by changing hatchery rearing conditions, but these changes are of limited effectiveness in reducing the difference between hatchery-reared and wild fish.

Effect of fluctuating flow and temperature on cover type selection and behaviour by juvenile brown trout in artificial flumes

“…In the present study, increased flow displaced trout on to the lower screen especially after first exposure to high flow. Present results support the view that subjecting hatchery trout to higher water velocities than they are used to, before introducing them to streams, may benefit the fish (Wiley et al, 1993;McDonald et al, 1998). The highest proportion of juvenile brown trout in these experiments, was displaced at low temperatures in winter.…”

Male competition and breeding success in captively reared and wild coho salmon (Oncorhynchus kisutch)

“…Phenotypic divergence (behavioral, morphological, and physiological) between cultured and wild salmon has been well documented and is related to the proportion of the life cycle spent in culture (Fleming et al , 1997McDonald et al 1998). Wild and hatchery-reared salmon differ in some characteristics, such as stamina and swimming performance (Mc-Donald et al 1998), which may be important in determining fighting ability.…”

Lack of trophic competition among wild and hatchery juvenile chum salmon during early marine residence in Taku Inlet, Southeast Alaska

“…Others have shown than salmon condition can be affected by trophic interactions between stocks and congeners (Beacham 1993;Perry et al 1996;Willette 2001), and can vary by location as well as within a stock (Paul and Willette 1997;Farley and Carlson 2000;Boldt and Haldorson 2004). The geneticallydistinct (Beacham et al 2009) H and W stocks in Taku Inlet could also represent physiologically-different (McDonald et al 1998) ecotypes with stock-specific life history traits and behaviors (Mason 1974;Groot and Margolis 1991;Kaeriyama and Ueda 1998) that influence their condition, residency, interactions, and potential for competition (Mortensen et al 2000).…”