FISHERY BULLETIN; VOL. 69. NO. 1 



Table 1. — Biological characteristics of 



the desert pupfish, Cyprinodon macularius, and other important fish in 

 research." 



1 Data compiled from: Borlow, 1958, 1961, Frost 

 Rugh, 1962; Trinkaus, 1967; Yomamoto, 1967. 



* Desert pupfish has not been recorded spowning 

 under the proper conditions [Bunnell, 1970). 



and Brown, 1967; Kinne and Kinne, 1962; Miller, 1970 (personol communication); New, 1966; 

 throughout the year in noture as have other species of pupfish but presumably would do so 



have been found in the field at temperatures 

 ranging from 8° to 44° C (Lowe and Heath, 

 1969; Kinne, 1960). 



Since it can be relatively easily spawned in 

 the laboratory, the desert pupfish is a good model 

 for the study of reproductive behavior. Nu- 

 merous and rapid behavioral sequences precede 

 the actual spawning act. On occasion, however, 

 fish in high spawning readiness eliminate many 

 behavioral sequences and commence spawning 

 immediately. When properly stimulated the fish 

 swim parallel to one another, the male slightly 

 behind the female, twist into an S-curve, and 

 spawn. Release of the gametes is accompanied 

 by a quivering movement of both fish. The 

 male wraps his anal fin under the female's vent 

 and fertilizes each e^g as it is extruded. The 

 female then dips, leaving the fertilized egg at- 

 tached to the substrate. This process is re- 

 peated until the female is spent, having spawned 

 50 to 200 eggs in about 2 hr under laboratory 

 conditions. In nature the female only rarely 

 spawns more than one or two eggs in succession 

 (Barlow, 1961). The mature male is easily rec- 

 ognized by his aggressiveness and his brilliant, 

 blue coloration. The pugnacious male ])upfish 

 must be separated in the laboratory from fe- 



males and other males. The determination of 

 the male to spawn, regardless of circumstances, 

 makes the pupfish a potentially valuable species 

 for classroom demonstrations. Barlow (1961) 

 has presented a complete and detailed descrip- 

 tion of the social and reproductive behavior of 

 the desert pupfish. 



LABORATORY REARING THE 

 DESERT PUPFISH FOR CONSERVATION 



Another value in rearing desert pupfish lies 

 in the preservation of the species. Today the 

 pupfish faces elimination from many areas of 

 its natural range due to predation and compe- 

 tition from exotic species and the modification 

 or destruction of its habitat. Lai-ge populations 

 of desert pupfish, once prevalent around the 

 Salton Sea, have been alarmingly reduced. At 

 the present rate of population reduction, the spe- 

 cies may well become extinct in this area in the 

 near future unless steps are taken to insure its 

 survival. Artificial rearing is one of the pos- 

 sible means. 



Coleman (1929) conducted an ecological sur- 

 vey of the Salton Sea for the California Depart- 



152 



