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Physiological Responses of Rainbow Trout (.Salmo gairdneri) to Electroshock
<br />CARL B. SCHRECK, ~ ROY A. WHALEYZ
<br />Department of Fisheries and Wildlife, Oregon State University, Corvallis, Oreg. 97331, USA
<br />MICHAEL L. BASS3
<br />Department of Biology, Oregon State University, Corvallis, Oreg. 97331, USA
<br />O. EUGENE MAUGHAN
<br />Virginia Cooperative Fishery Research Unit, Virginia Polytechnic Institute and State University,
<br />Blacksburg, Va. 24061, USA
<br />AND MARIO SOLA7.7_I
<br />Deportment of Fisheries and Wildlife, Oregon State University, Corvallis, Oreg. 97331, USA
<br />SCHRECK, C. B., R. A. WHALEY, M. L. BASS, O. E. MAUGHAN, AND M. SOLAZZI. 1976.
<br />Physiological responses of rainbow trout (Sa/mo gairdneri) to electroshock. J. Fish.
<br />Res. Board Can. 33: 76-84.
<br />Electroshocking elicited an immediate increase in plasma corticoid and lactate concentra-
<br />tions and thrombocyte:leucocyte ratio in rainbow trout (.Salmo gairdneri). Plasma glucose
<br />concentrations increased significantly after 3 h. Plasma protein, calcium, magnesium, and an-
<br />drogen levels were not measurably affected. Plasma lactate returned to preshock levels within
<br />3 h, but corticoid and glucose concentrations remained elevated for at least 6 h. The fish coughed
<br />violently or did no[ resume normal breathing rates for 60 s post shocking. Although breathing
<br />frequency did not increase, buccal pressure increased substantially and required at least I h to
<br />return to preshock levels. Cardiac activity was irregular. immediately after shocking, but no
<br />predictable alterations in rate were evident thereafter. The height of the T wave in ECGs
<br />increased markedly 1-3 min after shocking. The electrophoretic patterns of 13 isoenzymes from
<br />liver, white muscle, and plasma did not differ between fish captured by dipnet and those captured
<br />by electrofishing.
<br />Responses exhibited by fish to shocking are most likely attributable to combined effects of
<br />trauma, factors associated with paying off of an oxygen debt, and attributes associated with the
<br />general adaptation syndrome of stress. A substantial period of time of more than 6 h is required
<br />1'or fish to return to "normal" preshock conditions.
<br />SCHRECK, C. B., R. A. WHALEY, M. L. BASS, O. E. MAUGHAN, AND M. SOLAZZI. 1976.
<br />Physiological responses of rainbow trout (Sulmo gairdneri) to electroshock. J. Fish.
<br />Res. Board Can. 33: 76-84.
<br />Le traitement aux electroshocs a immediatement declenche chez la truitearc-en-ciel (Salmo
<br />gairdneri) une hausse des concentrations de corticoides plasmatiques et de lactate, de meme que
<br />du rapport thrombocyte:feucocyte. Apria 3 h, les concentrations de glucose dans le plasma
<br />avaient augmente de fa~on marquee. Par contre, les quantites plasmatiques de proteines, de
<br />calcium, de magnesium et d'androgene n'ont subi aucune variation mesurable. En 3 h, le lactate
<br />etait revenu a son niveau initial tandis que le glucose et les corticoides ont conserve une
<br />concentration elevee pendant au moins 6 h. Le poisson toussait violemment ou ne pouvant
<br />retrouver un rythme normal de respiration pendant les 6U s qui suivaient le traitement. Le rythme
<br />respiratoire n'augmentait pas, mais la pression buccale subissait une elevation importante qui
<br />mettait au moins 1 h avan[ de se stabiliser de nouveau. Le traitement a aussitiit engendre une
<br />irregularite des activites cardiaques qui n'a toutefois laisse prevoir aucun signe subsequent
<br />d'arythmie. Entre la premiere et is troisieme minute apria 1'experience, la hauteur de 1'onde T de
<br />'Present address: Oregon Cooperative Fishery Research Unit, Oregon State University, Corvallis, Oreg.
<br />97331, USA.
<br />zPresent address: W. F. Sigler and Associates, Inc., Reno, Nev. 89502, USA.
<br />'Present address: Department of Biology, Mary Washington College, Fredericksburg, Va. 22401, USA.
<br />Arinted in Canada (J3943 )
<br />Imprime au Canada (J3943 )
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