Author
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Davis Jr, Kenneth |
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Submitted to: North American Journal of Aquaculture
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/15/2005 Publication Date: 3/21/2006 Citation: Davis Jr., K.B. 2006. Management of physiological stress in finfish aquaculture. North American Journal of Aquaculture. 68:116-121. Interpretive Summary: Management of physiological stress is an important activity of raising fish. Stress is induced by many environmental conditions and can be measured by changes in plasma cortisol, glucose and plasma electrolytes. Stress responses can be beneficial under acute conditions but become detrimental if the stress is chronic. The stress response has been shown to be altered by hatchery conditions and by genetic selection. It is likely that the most desirable stress response for foodfish aquaculture might be different from that in fish raised for stocking into natural waters and other uses such as baitfish and aquarium trade. Fish domesticated for use in foodfish aquaculture might benefit from having a high tolerance for stress while a more robust stress response might improve survivability in the wild. A better understanding of the relationship between the environment and the stress response should allow the management and selection of those stress characteristics best suited for the purpose for which the fish are raised. Technical Abstract: Physiological stress is a non-specific response initiated by many types of environmental changes. Stress in freshwater fish can be characterized by changes in plasma cortisol, glucose, and electrolyte concentrations, and is quantitatively related to the severity and longevity of the stressor. Adrenalin from sympathetic nervous system activation is the most sensitive indicator to stress, followed by cortisol, and then glucose. Plasma electrolyte disturbances may not occur until the stress is severe and present for an extended time. Adrenalin increases plasma glucose by stimulating liver glycogenolysis, which represents energy loss to the fish. The activities of cortisol include induction of gluconeogenesis and suppression of the inflammatory response. Maintaining osmoregulatory homeostasis is an energetically expensive and disturbances deplete energy reserves. Acute responses to stressors may be beneficial to the fish while, chronic exposure to stressful conditions may result in decreased performance or survival. The physiological stress response has been shown to be altered by hatchery conditions and genetic selection. Management practices and selection pressures impact the stress response requiring the ultimate use of the fish be considered during the raising of the fish. Commercial foodfish aquaculture involves raising fish at very high densities and requires minimizing stressors such as water quality deterioration, disease treatment, and handling to maintain healthy growing fish. Fish raised for stocking into the wild might benefit from a more robust stress response to prepare them for survival. Present information does not yet allow for the selection of the most desirable stress response profile that would benefit fish raised for different purposes. |
