FISHERY BULLETIN: VOL. 80. NO. 2 



Figure 2.— Photomicrograph of Ancyrocephalus sp. on the gills of Lutjanus griseus, 22.0 cm SL, from southwest Biscayne Bay, 

 Fla. (PAS, 75X) showing hyperplasia, loss of respiratory epithelium, excessive mucus, lamellar fusion, and aneurisms, a) para- 

 site; b) mucus. 



in a similar manner (Fig. 3). In addition to injury 

 caused by the hooks of the parasite, the lamellae 

 were deflected and adhered to each other, thus 

 reducing the gill surface effective for gas ex- 

 change. In severe cases when a number of worms 

 were attached to the tips of filaments, clubbing 

 of filaments was almost always present, as was 

 obliteration of normal filament structure. The 

 affected filaments appeared white in fresh prep- 

 arations and the gills were congested with mu- 

 cus. 



Histological changes of the gills not associated 

 with parasites were found in hosts from south- 

 west Biscayne Bay stations. Few southeast Bis- 

 cayne Bay fish showed above-normal production 

 of mucus in the gills. Increased mucus produc- 

 tion was evident in all fish from the southwest 

 locations, and pathological changes ranged from 

 moderate to severe (Table 6). Abnormal color 

 changes were frequent in southwest Biscayne 

 Bay fish and were usually associated with over- 

 production of mucus which congested the gills. 

 Histological sections of gills from these fish 



showed that whole filaments were lined with 

 mucus and that it filled the spaces between the 

 filaments. Additionally, mucus-producing cells 

 were concentrated, sometimes in several layers, 

 at the tips of gill filaments which had lost their 

 normal structure. Fusion of gill lamellae along 

 entire filaments, epithelial hyperplasia, club- 

 bing of lamellae or obliteration of lamellar struc- 

 ture, aneurisms, and clubbing of filaments 

 occurred frequently, along with proliferation of 

 cells at the bases of lamellae. 



DISCUSSION 



According to Grundmann et al. (1976), hel- 

 minth populations in a natural environment are 

 well regulated to a point of host comfort. 

 Although the results from the southeastern habi- 

 tat in this study agreed with this statement, those 

 from the southwest bay locations did not. Disease 

 caused by parasites often requires exogenous as 

 well as endogenous factors (Sindermann 1979). 

 Exogenous factors, as defined by Cameron 



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