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<br />&~su1ts
<br />
<br />No significant differences (p >- 0.05) were observed
<br />between male and female fish in control values for
<br />hemoglobin, hematocrit, plasma protein, or percent tis-
<br />sue water content. Electroshocking did not afTect the
<br />hemoglobin, plasma protein, or percent water con-
<br />tent-the values did not differ significantly (P > D.05)
<br />from the controls or vary during recovery (Table 1).
<br />Hematocrit samples at 0, 3, and 5.5 h were signifi-
<br />cantly different (P <: 0.05). The difference may not be
<br />due to treatment effect, since there was a larger within-
<br />group variance than between-groups variance. We,
<br />therefore, do not believe that the shocking accounted for
<br />the observed changes.
<br />Lactate levels rose significantly due to shock in the
<br />1-h sample (P -< 0.05), returned to pre-shocked levels
<br />within 3 h, then declined below the control levels
<br />(Table 1).
<br />
<br />Discussion
<br />
<br />Blood characteristics of the control fish were similar
<br />to those which had been previously reported for this
<br />species (Black 1955; Denyes and Joseph 1956; Dean and
<br />Goodnight 1964; Smitherman 1965), but apparently
<br />hematocrit values cannot be used for sexual differentia-
<br />tion, as Steucke and Atherton (1965) suggested.
<br />Considerable variation exists in reported resting
<br />blood levels of lactate in largemouth bass, which range
<br />from 16.9 to 143.37 mg/dl (Black 1955; Denyes and
<br />Joseph 1956). The variation in these values may be from
<br />differences in fish handling techniques, sample size, or
<br />an environmental factor such as temperature (Dean and
<br />Goodnight 1964).
<br />Hemoglobin concentration did not change signifi-
<br />cantly (0.05 :> P :> 0.01), whereas hematocrit showed a
<br />significant change in the post-shock groups, although
<br />the large within-group variance raises some doubt as to
<br />its validity. A failure to induce a change in these blood
<br />
<br />values through this mode of collection was also noted by
<br />Schreck et al. (1976) in rainbow trouUSalmo gaire/neri).
<br />Muskellunge (Esox ma.'lquinongy) collected by shocking
<br />(Ae current) showed no increase in hemoglobin but had
<br />a significant increase in hematocrit (Miles et a1. 1974).
<br />Hemoconcentration in the muskellunge was attributed
<br />to fluid diuresis by Miles et a1. (1974), whereas Stevens
<br />(1968) suggested that this phenomenon might be the
<br />result of an extracellular to intracellular fluid com-
<br />partment shift. In the present study, largemouth bass
<br />experienced neither hemoconcentration nor a fluid com-
<br />partment shift, since the percentage of tissue water was
<br />not altered as a result of electroshocking.
<br />Plasma protein concentration as well as composition
<br />have been reported to change in fish subjected to dif-
<br />ferent types of capture methods (Bouck 1972; Fletcher
<br />1975), but electroshock does not cause a change in the
<br />concentration of plasma protein in either largemouth
<br />bass or rainbow trout (Schreck et a1. 1976).
<br />In general, any type of capture stress increases the
<br />blood lactate (Calliouet 1968; Miles et a1. 1974). The
<br />appearance of an elevated blood lactate level during the
<br />recovery phase in largemouth bass is probably not an
<br />immediate stress response and may be similar to that
<br />observed in fish stressed by other agents (Leivestad et
<br />al. 1957; Fraser and Beamish 1969). Leivestad et al.
<br />(1957) suggested that the delayed appearance oflactate
<br />may be due to circulatory bypass of the muscles and a
<br />slow return of this circulation following stress. The re-
<br />turn of blood lactate to pre-stressed levels varies from
<br />1 h in codfish (Gadus cal/arias) and 4-5 h in channel
<br />catfish (/ctalurus punctatus) to 12 h in electroshocked
<br />rainbow trout (Leivestad et al. 1957; Caillouet 1968;
<br />Schreck et al. 1976). Recovery of the blood lactate level
<br />may be explained by oxidation of the lactate (Bilinski
<br />and Jonas 1972), by its conversion into glycogen, or
<br />perhaps by its excretion by the kidneys (Miles et al.
<br />1974).
<br />Our findings on the effect of electroshock on certain
<br />blood chemistry values for largemouth bass indicate
<br />
<br />Table 1. Mean and (in parentheses) SE for blood chemistry characteristics and percentage tissue water content in
<br />largemouth bass" before and after the fish were electroshocked.
<br />
<br />_.._._--_..._--------~-----_.. - ---,-,._,_._.__.~-_.-
<br /> Plasma Tissue
<br />Time (h) after Hematocrit Hemoglobin Lactate protein water
<br />electroshocking (%) ( g/d)) (mg/dl) (mg/d)) (o/c )
<br />- --."------ -~------------ ----.----..-.--.- . ___n_______,__.
<br />Control 45,3 0.8) 8.15 (0.7) 46.56 (10.1) 6,16 (0.1) 78,81 (0,2)
<br />0 49,80 (2,6) 9,39 (0.1) 44,90 ( 6.0) 5.95 (0.3) 78,92 (0.9)
<br />] 44.33 (5.9) 8.21 (0.5) 111.53 ( 9.6) 5,80 (0.2) 79.820.1)
<br />3 40,92 (4,6) 8.04 (0.3) 33,69 ( 8.1) 6,0 (0.2) 78,68 (0,2)
<br />5,5 39.69 (6.91 8.06 (0.1) 16.41 ( 3.8) 5,92 (0,3) 79.12 (0.3)
<br />19 44.80 (6.1) 9,02 (0.6) 12.72 ( 1.5) 5,74 (0.5) 78.9 (0.3)
<br />
<br />3 Range in numbers of fish in different phases of each test (controls excluded) were as follows: hematocrit and hemoglobin, 5-12; lactate, 3-6; plasma
<br />protein, 5-8; and tissue water, 5-12. Control fish numbered 5 for lactate and 13-15 for the other characteristics.
<br />
<br />VOL. 40, NO.4, OCTOBER 1978
<br />
<br />149
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