ICHTHYOLOGY OF VENEZUELA — SCHULTZ 9 



Venezuela and of fresh-water species of fishes in the southern portion 

 where the great rivers enter. Thus, Lago de Maracaibo contains an 

 interesting mixture of marine, brackish, and fresh-water species. 

 Although the fish fauna of the lake is not adequately known at present, 

 enough knowledge has accumulated to indicate that the marine and 

 fresh-water species have adapted themselves to live in this body of 

 water, and in so doing some have changed a little structurally. These 

 have evolved into more or less separate biological units, recognized in 

 this report as either species or subspecies. 



Those families of fishes that are usually considered marine by 

 ichthyologists and that have representatives that have been found in 

 Lago de Maracaibo and in the Rio Orinoco are discussed below. 



In Lago de Maracaibo, sharks, sawfishes, and large stingrays were 

 reported, but I did not have an opportunity to fish for these. Sharks 

 are caught by fishermen as far south as off the mouth of the Rio Santa 

 Ana. The occurrence of sharks in fresh-water lakes with access to the 

 sea is not confined to Lago de Maracaibo. In Lake Nicaragua 

 Eulamia nicaraguensis occurs in abundance and reaches a large size. 



Among the elasmobranch fishes the stingrays of the family Dasyati- 

 dae have been most successful in evolving permanent species in South 

 American fresh waters. The genus Potamotrygon has one species in 

 the Rio Orinoco and the Guianas, another in the Rio Atrato, Rio 

 Magdalena, and Maracaibo Basins, and others farther south. These 

 fresh-water stingrays occur far upstream, the females when caught 

 often carrying young. 



Several other marine families of fishes have representatives in fresh 

 or brackish waters. The anchovies, or Engraulidae, have a few 

 species occurring regularly in the fresh waters of the Rio Orinoco and 

 of the Lago de Maracaibo and its tributaries. These belong to the 

 genera Anchoa and Lycengraulis in Venezuela. 



The tarpon, Tarpon atlanticus, and the tenpounder, Elops saurus, 

 are regular inhabitants of Lago de Maracaibo and in the lower courses 

 of its large tributary rivers. The needlefishes, family Belonidae, were 

 represented by Strongylura timuacu. The females, when taken at the 

 southern end of Lago de Maracaibo, contained mature eggs that 

 flowed from the vent with gentle pressure. This needlefish was taken 

 far up the Orinoco system in the Rio Apure. The Hemiramphidae, or 

 halfbeaks, were represented by Hyporhamphus roberti in Lago de 

 Maracaibo. 



Two genera of pipefishes, or Syngnathidae, namely Oostethus and 

 Pseudophallus, were found in the lower courses of rivers, probably in 

 brackish water. Soles of the family Bothidae, genus Citharichthys, and 

 tonguefishes, family Achiridae, of the genera Hypoclinemus, Achirus, 

 and Trinectes, regularly occm- in brackish water, a few venturing even 

 into fresh waters. 



