1968 Volume 34 Issue 12 Pages 1066-1071
To obtain the blood samples of the fish in the field, specimens which have just been caught by net or fishing-tackle are usually used. The influence of fright and stress, which may occur during the course of catch, on the blood elements was therefore examined to estimate the technical errors encountered in the study of the physiological ecology of fish from the haematological point of view.
Specimens were kept in a concrete tank (0.7m3) during the period of experiment (January 14-February 1, 1967) after 19 days of acclimation there. Apparently only healthy specimens were used. In order to induce the effect of stress, a portion of the lower jaw of the rockfish was hooked using a short angling rod (40cm) furnished with a thread 20cm long, which forced the specimens to swim continuously in the tank during 3 different periods of time, i.e. 5, 10 and 30 minutes. Sampling of the blood, measurement of specific gravity, haematocrit, urea nitrogen level of serum, and serum protein and also the electrophoresis were all conducted with the identical techniques used in the previous investigations3, 4, 5).
The specific gravity of the blood, haematocrit value (exclusive of the resting fish), total serum protein and the urea nitrogen level of serum did not differ in the resting specimens or in the exercised specimens, according to the sex (Tables 1 and 2).
The quantity of total serum protein for exercised fish was larger than that of resting one both in the male the female (Tables 1 and 2). Urea nitrogen of serum for resting fish could not be detected irrespective of sex (Table 1). On the other hand, values higher than 15.0mg/100ml were obtained from exercised specimens in both the male and the female (Table 2).
The electrophoretic pattern of serum protein in resting specimens indicated clearly 5 fractions. Component-IV of the male was larger than that of the female, while Component-V of the female was much larger than that of the male (Table 3, Fig. 1). Five peaks of serum protein were also observed in exercised specimens. The percentage of each fraction was similar to that of the resting fish in each sex (Table 4, Fig. 2).
