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Fish Physiology (program)
Our research is directed to two main areas in fish biology: stress and reproduction. The overall goal has been to understand the actions of natural and artificial (anthropogenic) substances/stressors at the whole organism level. The studies address fundamental and applied aspects of fish biology such as stress, reproductive endocrinology, and reproductive development (sex differentiation and sex control).
Stress
We aim to understand the functional significance of the physiological responses to stressors in fish. The effects of stressors are evaluated at different levels of the organism organization (growth, survival, endocrine (corticosteroid and sex steroid hormones), metabolic (glucose), and cellular responses). We also address aspects such as individual variation and sex-related differences in response to different stressor. In collaboration with other IMB teams, we are using a multidisciplinary approach to develop reliable indicators of the stress response in fish for a variety of applications.
Reproduction
In this area we have addressed aspects such as the role of the sex steroid hormones during sexual maturation, the mechanisms involved in sex determination and sex differentiation in fish and how exogenous substances can affect reproductive development.
Our Instrumentation:
Analytical Instruments: Handling an array of applications including: Microbial growth/MIC, IC 50s/LD 50s, Endpoint ELISA, Cytoproliferation/Cytotoxicity, Colorimetric protein analysis, Kinetic ELISAs/Enzyme assays, Platelet aggregation, Bacterial identification, Clotting/Clot lysis, Protein determination, RNA extraction, Spectrophotometric analysis of lactate, and glycogen.
Our Projects
 Characterization of the stress response in gadoid fish:
Our goal is to understand how haddock and cod respond to several stressors such as handling, anaesthesia, and thermal shock and then develop practices to minimize stress in aquaculture operations.
Effects of stress on vaccine response in fish: Studies in mammals and other vertebrates have shown that long-term stress can cause immune suppression.
Functional significance of corticosteroid-binding protein (CBP) in fish: These proteins have an important role of controlling the amount of cortisol entering the target cells. We wish to understand the role these proteins play during the stress response in fish.
The corticosteroid response to stress: free and bound cortisol in fish: The stress hormone cortisol can circulate in the blood free or bound to proteins (corticosteroid-binding proteins -- CBP). We want to determine whether there is a variation between the free and bound fraction in fish exposed to acute and chronic stressors.
Our Facilities
 Fish Physiology (facility)
Our Publications  |
Leggatt, R.A., Scheer, K.W., Afonso, L.O.B. and Iwama, G.K. 2006. Triploid and diploid rainbow trout do no differ in their stress response to transportation. North American Journal of Aquaculture, 68:1-8. [view] |
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Iwama, G.I., Afonso, L.O.B., Todgham, A., Ackerman and Nakano, K. 2004. Are hsps suitable for indicating stressed states in fish? Journal of Experimental Biology, 207:15-19. [view] |
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Balfry, S.K. and Iwama, G.K. 2004. Observations on the inherent variability of measuring lysozyme activity in coho salmon (Oncorhyncus kisutch). Comparative Biochemistry and Physiology, Part B, 138:207-211. [view] |
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