Relationship of season, thermal loading and red‐sore disease with various haematological parameters in Micropterus salmoides

Abstract

One hundred and fifty largemouth bass (Micropterus salmoides) were caught during the mid-winter and mid-summer months in Par Pond, an 1120 ha cooling reservoir located on Savannah River Plant near Aiken, SC. Equal numbers of fish were taken from ambient and thermally altered (> 10" C ambient) areas of the lake. The total length and weight of each bass was noted, along with the presence or absence of lesions associated with red-sore disease (caused by the bacterium, Aeromonas hydrophila and the ciliate, Epistylis sp.). Blood was drawn, by heart puncture, from each bass and the following haematological parameters measured: haematocrit, haemoglobin, iron, total iron-binding capacity, thyroxine, sodium and potassium. Only the total iron-binding capacity was significantly higher in bass with red-sore disease; none of the other blood parameters were significantly different in infected and uninfected bass. Bass from thermally altered locations had consistently higher haematocrits during both summer and winter. Bass from thermal and ambient locations were not different with respect to iron, iron-binding capacity, sodium or potassium levels. However, bass taken during summer months had higher levels of circulating iron than individuals in winter months. Summer bass had higher thyroxine levels than bass in winter. These results are discussed in terms of their relationship to red-sore disease, season and the impact of thermal effluent.

Histologic, immunologic and endocrine biomarkers indicate contaminant effects in fishes of the Ashtabula River

“…Although seasonal changes in thyroid hormones are common in fish (Leatherland 1982), there is limited published information on plasma thyroid hormones in these two species. Hazen et al (1978) observed higher levels of plasma T 4 in summer compared to winter in a reservoir population of largemouth bass. Spring increases in both plasma T 4 and T 3 were observed in feral populations of brown bullhead (Burke and Leatherland 1983).…”

Histopathology of red‐sore disease (Aeromonas hydrophila) in naturally and experimentally infected largemouth bass Micropterus salmoides (Lacepede)

“…Severe haemorrhagic necrosis of gill lamellae and filaments; haemorrhagic necrosis and inflammation of underlying supporting tissues (x35). Rased on the infection scheme proposed hy , and on ohservations generated in the present study, we believe that the pathobiology of red-sore disease among largemouth bass in Par Pond follows a clear pattern: namely, elevated water temperature stimulates increased metabolism of bass, resulting in increased catabolism of stored fat and protein; body conditions of these bass then decline according to the duration and magnitude of exposure to elevated temperature Hazen, Esch, Glassman & Gibbons, 1978). Increased temperatures either directly, or indirectly for bass with lowered body conditions, cause increased production and release of ACTH which, in turn, stimulates production and release of corticosteroids, primarily cortisol.…”

Distribution of Aeromonas hydrophila in natural and man-made thermal effluents

“…Recent studies have shown that the incidence of redsore disease is significantly higher among fish in thermally altered parts of a South Carolina reservoir that receives heated effluent from a nuclear production reactor (4). The positive correlation between red-sore disease and thermal effluent was related to thermal stress on potential fish hosts (3,7). A more recent study demonstrated a significant positive correlation between densities of A. hydrophila in the water column and the incidence of red-sore disease in the fish population over a 3-year period (T; C. Hazen, Ph.D. thesis, Wake Forest University, Winston-Salem, N.C., 1978).…”