SKINNER: INTERRELATION OF WATER QUALITY, GILL PARASITES. AND GILL PATHOLOGY 



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Figure 3.— Photomicrograph of two Aneyrocephalus partus on the gills of S. timncu, 24.3 cm SL, from southwest Biscayne Bay, 



Fla. (PAS, 300X). Lamellae are deflected and obstructed, a) and b) parasites. 



(1958), are alterations in the ecology of the para- 

 sites or hosts by some abnormal or unnatural 

 event, most often manmade. 



The most outstanding difference between the 

 southeast Biscayne Bay and southwest locations 

 was the difference in chemical water quality. 

 According to Klontz (1972), fish are so intimately 

 associated with their aqueous environment that 

 physical or chemical changes in this environ- 

 ment are often rapidly reflected as measurable 

 physiological changes in the fish. In general, re- 

 actions of fish gills to an irritant include inflam- 

 mation, hyperplasia, lamellar fusion, excessive 

 mucus production, clubbing of filaments or la- 

 mellae, and formation of aneurisms. 



Aneurisms may be a specific tissue reaction 

 due to injury or toxic substances, especially am- 

 monia or herbicides in the water or food (Eller 

 1975). Ammonia frequently has been reported to 

 cause extensive gill damage. Although much of 

 the data on the degree of toxicity of ammonia is 

 not satisfactory (National Academy of Sciences 

 Environmental Studies Board 1972), it has been 

 shown that the more toxic component of ammonia 



solutions is the unionized ammonia (NH3). An in- 

 crease in pH from the normal level increases the 

 toxicity, because along with temperature it con- 

 trols the degree of dissociation (Trussel 1972). A 

 decrease in dissolved oxygen concentration in- 

 creases the toxicity of unionized ammonia (Na- 

 tional Academy of Sciences Environmental 

 Studies Board 1972). Even low concentrations 

 may cause pathological changes in marine and 

 freshwater organisms (Doudoroff and Katz 

 1950; Flis 1968; Larmoyeux and Piper 1973). In 

 addition to exhibiting gill damage, after expo- 

 sure to NH 3 freshwater fish were susceptible to 

 ectoparasites, according to Reichenbach-Klinke 

 (1966). Prolonged exposure to nonlethal dosage 

 of ammonia in salmon led to hyperplasia of gill 

 epithelium and epizootic bacterial gill disease in 

 a study by Burrows (1964). 



Pollutants such as metals and pesticides show 

 similar effects on fish gills (Gardner 1975). The 

 LC50 and sublethal effects of pesticides are pres- 

 ently under scrutiny. According to Anderson 

 (1971), for pollutants not to influence the physiol- 

 ogy and behavior of fish, "safe" concentrations 



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