7119 ‎(2)‎

• UCREFRP Catalog Number: 7119
• Author: Emery, L.
• Title: Physiological effects of electrofishing.
• USFW Year: 1984.
• USFW - Doc Type: February 3-4, 1984.
• Copyright Material: NO

levels in the blood doubled immediately after the fish were. shocked and remained high for
one hour and recovered to preshock levels after approximately six hours. The rapidity of
lactate increase after shocking reflects the severity of the period of anaerobic muscular
activity. Schreck's et a1. (1976) lactate increases after shocking were much the same as
those found by other researchers for different species (Johnson et al. 1956, Caillouet 1967,
Burns 1978). The recovery is also similar to that observed in rainbow trout that have
undergone strenuous muscular excerise (Black et al. 1960). Other blood chemistry changes
occur as a result of shocking. For example, glucose follows a reaction similar to lactate
except the increase is not as abrupt and recovery takes longer (up to 12 hours) (Schreck
et al. 1976). The U. S. Environmental Protection Agency has recommended that fish collected
by electrofishing not be used in physiological or bioassay studies because of blood
chemistry changes (Weber 1973).
2t
15
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5
Time AFter Shock (h)
Fi:gure 5. Average concentrations (mg/100 ml) of lactate (vertical
line at top of each bar shows range) levels in plasma
of electroshocked and unshocked rainbow trout (adapted
from Schreck et al. 1976).
Fish differ greatly in their ability to carry oxygen in the blood (Table 3). The amount of
oxygen in the blood can play an important role in breaking down metabolites released into
the blood following electrofishing or in determining the overall vitality of a fish.
Temperature of the water (the cooler the better) and life stage of the fish can also affect
the amount of oxygen in the blood.
CAL-NEVA WILDLIFE TRANSACTIONS 1984
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