ICHTHYOLOGY OF VENEZUELA — SCHULTZ 5 



Considerable destruction of fish life is undoubtedly caused by oil 

 wells in the lake near the eastern shore for a distance of about 80 km. 

 Far out into the lake the surface is more or less covered with a film of 

 oil. At times and in certain places the petroleum forms a thick scum 

 on the surface, and as the volatile portions evaporate the tarry residue 

 becomes thicker and thicker, finally settling into the water in tiny 

 to large globules. These, while suspended in the water, drift with the 

 wind across the lake and saturate the beaches, covering the aquatic 

 plants and shore vegetation and the bottom with a layer of petroleum, 

 making existence for fish life very hazardous. Unless this oil leakage 

 can be stopped the northern end of Lago de Maracaibo, at least, may 

 become rather barren, the sources of fish-food production exterminated, 

 and the possibilities of extensive and valuable fisheries in the future 

 greatly reduced. 



These great shallow bodies of water with large rivers emptying into 

 them should be considered one of Venezuela's great natural resources. 

 Together with the Gulf of Paria and the Rio Orinoco and its delta they 

 are capable of producing many millions of tons of fishery products 

 annually. If they were developed and properly controlled a maxi- 

 mum yield would result from a minimum of fishing effort. Such a 

 balanced condition between fishing and natural reproduction of fishes 

 can be obtained only through unbiased studies by adequately trained 

 fishery biologists and ichthyologists, who would recommend the 

 proper controls for the various fisheries. 



DISTRIBUTION OF FRESH-WATER FISHES 



In this report the fresh-water fish fauna of Venezuela is considered 

 as including those families whose genera and species are predomi- 

 nantly permanent inhabitants of fresh waters and which, except for 

 the Cyprinodontidae, enter brackish waters only more or less as 

 stragglers. Such families are: Pimelodidae, Callophysidae, Auchen- 

 ipteridae, Ageneiosidae, Bunocephahdae, Cetopsidae, Pygidiidae, 

 Doradidae, Callichthyidae, Astroblepidae, and Loricariidae (all 

 catfishes), and in addition the Characinidae, Sternarchidae, Gymno- 

 tidae, Electrophoridae, Cyprinodontidae, Poeciliidae, Synbranchidae, 

 Polycentridae, and Cichlidae. 



The relationships and derivation of the fresh-water fish faunas of the 

 various stream systems of Venezuela cannot be worked out at this 

 time with any degree of certainty because the various species of fishes 

 occurring in many of the drainage systems are as yet little known or 

 unknown. 



A list of drainage basins or stream systems of northern Venezuela is 

 presented below to aid in the interpretation of this report. Each 

 indentation indicates that the body of water is tributary to the one 

 under which it is indented. 



