FISHERY BULLETIN: VOL. 84, NO. 4 



13 



11- 



100 Artemia, liter" 1 



E 

 E 



o) 5 



c ~^- 



o 



-J 15r 



CO 

 ■D 



« 13 r 



CO 



11 



9 



500 Artemia, liter -1 



_i i i_ 



6 8 10 13 16 19 25 



Days after Hatching 



30 



Figure 1.— Mean standard lengths +2 standard errors of striped bass 

 (SB), striped bass x white bass (WBX), and striped bass x white perch 

 (WPX) larvae from 6 to 30 d after hatching, reared at two food levels in 

 the laboratory. 



white bass hybrid and white perch hybrid rates were 

 significantly higher than that for striped bass lar- 

 vae (SNK multiple comparison procedure, P < 

 0.05). 



Weight-Length Relationships 



The wet weight-standard length relationships dif- 

 fered significantly among the three types of larvae 

 (ANCOVA, P < 0.001). The power coefficient of the 

 white bass hybrid larvae was higher than those of 

 the striped bass and white perch hybrid larvae (SNK 

 multiple comparison test, P < 0.01) (Table 4F). 



Pond Zooplankton 



Copepod nauplii and adults (Diaptomus spp. and 

 other calanoid species) and cladocerans (Bosmina, 

 Scapholebris, Ceriodaphnia, and Daphnia) were 



abundant in the pond and in the enclosures (Fig. 5). 

 The summed cladoceran and copepod densities 

 declined rapidly in the pond from >1,000 L _1 , 

 when the larvae were stocked, to approximately 400 

 L _1 during the last 10 d of the experiment. Den- 

 sities within the enclosures declined from approx- 

 imately 1,000 L _1 at the time larvae were stocked 

 to 100 L _1 when the experiments ended. 



Samples of 12-20 larvae of each type were ex- 

 amined for stomach contents on day 30. The small- 

 est larvae of each type had eaten cladocerans and 

 copepods. The largest individuals had eaten chirono- 

 mid larvae and zooplankton. Two of 20 individuals 

 of striped bass and white bass hybrids had eaten fish 

 larvae, proof that cannibalism was occurring. 



DISCUSSION 



Neither striped bass nor hybrid larvae, in the lab- 



910 



