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United States Department of Agriculture

Agricultural Research Service

Research Project: VACCINOLOGY AND IMMUNITY OF AQUATIC ANIMALS Title: Stress in Fish

Authors
item Pasnik, David
item Evans, Joyce
item Klesius, Phillip

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: February 6, 2009
Publication Date: February 3, 2010
Citation: Pasnik, D.J., Evans, J.J., Klesius, P.H. 2010. Stress in Fish. Book Chapter in Fundamentals of Ornamental Fish Health. editor Helen E. Roberts. chapter 3, pages 33-38. Wiley-Blackwell, Ames, IA.

Interpretive Summary: Stress in fish involves a condition disruptive of physiological homeostasis that occurs in response to unfavorable external influences and is capable of adversely affecting fish. Any stimulus that provokes stress responses is known as a stressor, disrupting a stable condition and causing a response. While stress is an adaptive response, it can become detrimental if stressor exposure is acute or chronic in nature. Several stressors are routinely encountered in fish husbandry. Though stress represents a complex, dynamic process, the stages of stress are often put into basic categories for simplicity. If stressors are present or intensified, the fish may have initial behavioral changes and then primary, secondary, or tertiary stress responses. Initial behavioral changes may occur within seconds to minutes of the stressor exposure. Fish presumably act to avoid harmful stimuli. Primary responses involve increased corticosteroid and catecholamine hormone release (e.g. cortisol, epinephrine, norepinephrine) and may begin within seconds to hours later. Secondary stress responses include changes in hematological, metabolic, and hydromineral values (e.g. blood glucose and lactate, liver and muscle glycogen, osmolality) and may also begin within minutes to hours later. Tertiary responses involve changes in whole-fish behavior and performance (e.g. homeostasis disturbances) and may begin minutes to days after stressor exposure. This is the most apparent stage. Fish health professionals can determine stress levels and their impact based on a combination of history, observation, and diagnostic tests. Since stressors can have a major impact on fish health, one of the most important components of a fish management plan is the prevention or management of stress in fish. Stress can be prevented or mitigated through recommended husbandry practices that target the common causes. The information in this chapter provides an initial guide to fish stress biology, stressors, diagnosis, and management. Given the numerous fish species and indefinite environmental conditions throughout the world, continual research is required to definitively understand the impact of species biology, genetics and environment on stress. Thus, fish health professionals can deal with fish stress and welfare as a dynamic subject with continual learning experiences.

Technical Abstract: Stress in fish involves a condition disruptive of physiological homeostasis that occurs in response to unfavorable external influences and is capable of adversely affecting fish. Any stimulus that provokes stress responses is known as a stressor, disrupting a stable condition and causing a response. While stress is an adaptive response, it can become detrimental if stressor exposure is acute or chronic in nature. Several stressors are routinely encountered in fish husbandry. Though stress represents a complex, dynamic process, the stages of stress are often put into basic categories for simplicity. If stressors are present or intensified, the fish may have initial behavioral changes and then primary, secondary, or tertiary stress responses. Initial behavioral changes may occur within seconds to minutes of the stressor exposure. Fish presumably act to avoid harmful stimuli. Primary responses involve increased corticosteroid and catecholamine hormone release (e.g. cortisol, epinephrine, norepinephrine) and may begin within seconds to hours later. Secondary stress responses include changes in hematological, metabolic, and hydromineral values (e.g. blood glucose and lactate, liver and muscle glycogen, osmolality) and may also begin within minutes to hours later. Tertiary responses involve changes in whole-fish behavior and performance (e.g. homeostasis disturbances) and may begin minutes to days after stressor exposure. This is the most apparent stage. Fish health professionals can determine stress levels and their impact based on a combination of history, observation, and diagnostic tests. Since stressors can have a major impact on fish health, one of the most important components of a fish management plan is the prevention or management of stress in fish. Stress can be prevented or mitigated through recommended husbandry practices that target the common causes. The information in this chapter provides an initial guide to fish stress biology, stressors, diagnosis, and management. Given the numerous fish species and indefinite environmental conditions throughout the world, continual research is required to definitively understand the impact of species biology, genetics and environment on stress. Thus, fish health professionals can deal with fish stress and welfare as a dynamic subject with continual learning experiences.

Last Modified: 10/30/2014
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