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Fishery Bulletin 89(1), 1991 



longer to die (23.842 ± 10.035 (SD) days 

 vs. 21.75 ± 7.063 days), this difference 

 was not significant. 



Intermolt duration data (Fig. 2) showed 

 that the brine shrimp-fed group in fil- 

 tered seawater took significantly longer 

 to molt (by 1 day) into Stage VI than the 

 mesoplankton-fed group (10.412 ± 1.502 

 days vs. 11.389 ± 1.243 days; Student's 

 r-test, P< 0.025). Data are not available 

 on the intermolt period between Stages 

 V and VI for the brine shrimp-fed group 

 in unfiltered seawater. There was no 

 significant difference between the groups 

 brine shrimp-fed in filtered seawater, 

 brine shrimp-fed in unfiltered seawater, 

 and mesoplankton-fed for the intermolt 

 periods between Stages VI and VII 

 (14.857 ±2.035 vs. 13.444 ±1.653 vs. 

 14.059 ± 1.853 days) and Stages VII and 

 VIII (22.0 ± 7.810 vs. 20.556 ± 4.681 vs. 

 20.529 ± 2.528 days). However, the in- 

 termolt periods of both brine shrimp-fed 

 groups were significantly different 

 (18.0 ± 1 and 16.842 ± 2.292 days; 1-way 

 ANOVA, P<0.001; Tukey test, P< 

 0.001) from those of the mesoplankton- 

 fed group (36 ± 5.057 days) for the molt 

 between Stages VIII and IX, with the 

 two brine shrimp-fed groups taking 

 nearly half the time of the mesoplank- 

 ton-fed group to molt into Stage IX. 



There was no significant difference 

 between any of the groups brine shrimp- 

 fed in filtered seawater, mesoplankton- 

 fed, meso/microplankton combination-fed, and starved 

 lobsters at the beginning of the experiment in either 

 weight (0.06 ± 0.011 vs. 0.066 ± 0.011 vs. 0.059 ± 0.009 

 vs. 0.061 ±0.011g, respectively; Fig. 3) or carapace 

 length (4.66 ± 0.214 vs. 4.761 ± 0.214 vs. 4.739 ± 0.236 

 vs. 4.716 ± 0.236mm respectively; Fig. 4). Although 

 measurements are not available for the brine shrimp- 

 fed group in unfiltered seawater, they probably did not 

 differ significantly from the other groups since they 

 were maintained in conditions identical to their siblings 

 until immediately before the molt to Stage V. Each of 

 the surviving groups of lobsters fed brine shrimp in fil- 

 tered seawater, brine shrimp in unfiltered seawater, and 

 mesoplankton showed significant growth (Student's t- 

 test, P<0.001) in terms of both increased weight and 

 carapace length (Figs. 3 and 4). However, final (Stage 

 IX) weights did differ between groups (1-way ANOVA, 

 P< 0.001). The weight of the brine shrimp-fed group in 

 unfiltered seawater (0.837 ±0.117 g) was significantly 

 greater (Tukey test, P<0.001) than that of both the 



Brine Shrtmp/Unflltered Seawater 

 Brine Shrimp/Filtered Seawater 

 Mesoplankton 



CH 



Stage V to VI 



Stage VI to VII 



Stage VII to vni 



Stage VIII to LX 



MOLT PERIOD 



Figure 2 



Mean intermolt durations for lobsters on each of three diet regimes: brine shrimp 

 in unfiltered seawater, brine shrimp in filtered seawater, and mesoplankton 

 (95-1000/jm) in filtered seawater. Bars indicate standard deviation values. 

 ( a ) Stage VI molt date missed for one lobster, so intermolt period could not be 

 determined for Stages V-VI and VI-VII for that lobster. ( b ) Stage VII molt 

 date missed for one lobster, so intermolt period could not be determined for 

 Stages VI-VII and VII-VIII for that lobster. ( c ) Stage IX molt date missed 

 for one lobster, so intermolt period could not be determined for Stages VIII-IX 

 for that lobster. 



brine shrimp-fed group in filtered seawater (0.484 ± 

 0.183g) and the mesoplankton-fed group (0.484 ± 0.037 

 g). However, there was no significant difference between 

 the latter two groups. Final (Stage IX) carapace lengths 

 did not differ between the three surviving groups (brine 

 shrimp-fed in filtered seawater, 9.9 ± 1.353 mm; brine 

 shrimp-fed in unfiltered seawater, 10.459 ± 0.564mm; 

 mesoplankton-fed, 9.907 ± 0.732mm). 



There was no significant difference in the wet 

 weights of each diet fed the lobsters. The average wet 

 weights of the diets were 0.408 ± 0.095g for the meso- 

 plankton; 0.364 ± 0.108g for the meso/microplankton 

 combination diet; and 0.391 ± 0.072g for the brine 

 shrimp diets. The mesoplankton diet consisted pre- 

 dominantly of Acartia copepods, barnacle nauplii, 

 pagurid shrimp zoea, invertebrate eggs, brachyuran 

 crab zoea, foraminifera, centric and pennate diatoms, 

 and marine algae, with occasional instances of ascidian 

 tadpoles, barnacle exoskeletons, fish eggs and young, 

 amphipods, hydroids, brachyuran crab prezoea, 



