SAN MARCOS GAMBUSIA Gambusia georgei (Hubbs and Peden. 1969) 



Order: ATHERINIFORMES Family: POECILIIDAE 



Distinguishing characteristics : A pale Gambusia with the dorsal fin orange, followed by 

 a dark margin, as the most pronounced colors. 



Present distribution : San Marcos River within 1 kilometer of U.S . Interstate 35 bridge 

 (both sides) . 



Former distribution : Probably the same as at present. 



Status : Occurs only in the river where the water is quiet and the aquatic vegetation is 

 minimal. Its presence is governed by the frequency of this environment. 



Estimated numbers : Fewer than 1,000 . 



Fecundity : Approximately 25 young per female per month. 



Reasons for decline : Unknown because of lack of history . 



Protective measures already taken : None . 



Measures proposed : Maintenance of this segment of the stream in its natural condition . 



Number in captivity : Approximately 100 . 



Breeding potential in captivity : Approximately 30 young per female per month. 



Remarks : Data provided by Dr. Clark Hubbs, University of Texas, Austin. 



Reference : 



Hubbs, C. and A. E. Peden. 1969. Gambusia sp ■ nov. from San Marcos, Texas. 

 Copeia, 1969, p. 357-364. 



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