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



Table 5.— Pesticides (/ug/1) in southwest Biscayne Bay location 

 of Black Creek Canal, Fla., from July 1975 to August 1976 

 (USGS unpubl. data). 1 



'Pesticides not found present in Black Creek Canal water samples were: 

 Aldrin. Chlordane. DDD, DDE. DDT. Dieldrin. Endrin, Ethion, Heptachlor, 

 Heptachlorepoxide. Lindane. Malathion, Methyl-parathion, Methy Itrithi- 

 on, PCB, Toxaphene. Trithion. and 2,4,5-T. 



2 0,0-Diethyl 0-(2-isopropyl-6-methyl-4-pynmidinyl) phosphorothioate 



3 2,4-Dichlorophenoxy (acetic acid). 



4 2-(2.4.5-Trichlorophenoxy) propionic acid. 



5 0,0-Diethyl-0-p-nitrophenyl phosphorothioate 



west bay was found to be the highest in nutrients 

 and trace metals. Direct sources of pollution may 

 have been waste discharge from boats, marinas, 

 agriculture, suburban developments, and the 

 nearby county dump. Slightly lesser amounts 

 were found at the Moody and Mowry stations 

 which were located some distance from inhabited 

 areas. Pesticide data were not available from the 

 Moody and Mowry stations, although chemical 

 pest and weed control conducted at the time 

 along the banks and in the vicinity of the canals 

 would have been a direct source of pesticides in 

 the water. 



Parasites 



The parasite fauna in both the southeast and 

 southwest Biscayne Bay habitats was similar in 

 kind for all three hosts, consisting mainly of pre- 

 viously reported ectoparasites of marine fishes of 

 the same and related species or those sharing 

 similar habitats. The three monogenetic gill 



parasites — Neodiplectanum wenningeri, Ancyro- 

 cephalus sp., and A. parvus— showed close to 

 100% incidence and were therefore suitable for 

 this study. Incidence of infestation was as fol- 

 lows: N. wenningeri on G. cinereus, 97% in south- 

 east Biscayne Bay, 100% in southwest Biscayne 

 Bay locations; Ancyrocephalus sp. on L. griseus, 

 100% in southeast Biscayne Bay, 100% in south- 

 west Biscayne Bay; A. parvus on S. timucu, 100% 

 in southeast Biscayne Bay, 100% in southwest 

 Biscayne Bay. 



The difference in intensity of infestation of 

 hosts by these parasites was striking, with few 

 parasites on host gills from the southeast loca- 

 tions and extremely large counts on hosts from 

 the southwest locations (Table 6). 



Pathological Changes in Host Gills 



Neodiplectanum wenningeri created compara- 

 tively little histological disturbance of the gills 

 when infestation was light. Damage was often 

 mechanical and gill lamellae were deflected. In 

 severe cases of infestation, however, the lamellae 

 were covered with N. wenningeri, and an in- 

 crease in mucus production was noticed along 

 with clubbing of filaments where parasites were 

 attached. Similarly, when numerous, Ancyro- 

 cephalus sp. and A. parvus caused pathological 

 changes at the site of attachment. Localized host 

 reaction to the parasites' hooks included epithe- 

 lial hyperplasia and heavy mucus production 

 (Fig. 2), and the respiratory epithelium was lost 

 in some instances. Often the side of the filament 

 opposite the worm attachment was also affected 



Table 6.— Averages of some nutrients, trace metals, and pesticides in water samples, and Monogenea and 

 gill pathology of the three host species in southeast Biscayne Bay and southwest Biscayne Bay at Black 

 Creek Canal from May 1975 to August 1976. 



Slight = mucus production above normal: moderate 

 of lamellae, loss of structure. 



 heavy mucus production and epithelial hyperplasia; severe = fusion 



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