PEARSE FISHES OF LAKE VALENCIA, VENEZUELA 47 



GENERAL REMARKS ON PARASITES 



Fourteen of the twenty-five parasites found in fishes were 

 confined to a single host. This may be taken to indicate that 

 the fish fauna of the lake is rather recent or that the parasites 

 have a high degree of host specificity, but the knowledge is too 

 limited to generalize in this connection. 



The fishes with the greatest infection by parasites are as 

 follows: 



1. According to total number of fishes infected: Creagrutus 

 beni, Chaetostomus pearsei, Rhamdia quelen, Hoplias malabaricus, 

 Crenicichla geayi. 



2. According to average number of parasites per individual: 

 Crenicichla geayi, Hoplias malabaricus, Aquidens pulcher, 

 Creagrutus beni, Astyanax bimaculatus. 



3. According to number of species of parasites: Astyanax 

 bimaculatus, Aquidens pulcher, Hoplias malabaricus, Crenicichla 

 geayi, Gephyrocharax valenciae. 



Fishes having the fewest parasites were as follows: 



1. According to total number of fishes infected: Gephyro- 

 charax valenciae, Symbranchus marmoratus, Curimatus argenteus, 

 Pimelodella metae, Aquidens pulcher. 



2. According to average number of parasites per individual: 

 Pimelodella metae, Astyanax metae, Lebistes reticulatus, Gephyro- 

 charax valenciae, Chaestomus pearsei. 



3. According to number of species of parasites: Astyanax 

 metae, Chaetostomus pearsei, Pimelodella metae, Creagrutus beni, 

 Rhamdia quelen, Lebistes reticulatus, Curimatus argenteus. 



In general the fishes with the most restricted habitat have a 

 high number of individuals infected, but carry few species of 

 parasites and have a small average number of parasites per 

 individual. The most abundant fishes, which have a variety of 

 food, including other fishes, and a wide range in habitats, gener- 

 ally have the most parasites in all respects. There are three 



