Fishery Bulletin 89(3). 1991 



throughout the sampled temperature 

 range, but were not collected at salin- 

 ities of < 22 x 10" 3 (Fig. 3). Maximum 

 abundance and frequency of occurrence 

 were both associated with salinities of 

 about 26 x 10 -3 . Somewhat surprising- 

 ly, paralarval L. brevis were collected 

 throughout the range of dissolved oxy- 

 gen concentrations sampled, including 

 waters considered to be hypoxic, with 

 <2mL/L dissolved oxygen (Fig. 4). 



Diel variability Mean abundance and 

 mean DML were compared between the 

 night and day samples at the same sta- 

 tions on the same day. Abundance was 

 somewhat greater during daytime (day 

 2.9/100 m 3 ; night 1. 7/100 m 3 ), speci- 

 mens caught at night tended to be some- 

 what larger (mean DML: day 2.0mm; 

 night 2.3 mm), but neither of these dif- 

 ferences was statistically significant at 

 the a priori a-level (/-test: abundance 

 P 0.276, size [DML] P 0.600). 



Vertical distribution Paralarvae 

 were much more abundant nearbottom 

 (mean abundance 4.7/100 m 3 ) than 

 nearsurface (0.7/100 m 3 ). Statistically, 

 this trend was very significant (i-test, 

 P<0.0001). The paralarvae collected 

 nearbottom were significantly larger 

 (mean DML 2.1mm) than those col- 

 lected nearsurface (1.6mm, /-test, 

 P 0.049). 



Variability among stations Abun- 

 dance tended to be greater inshore at 

 station M21 than farther offshore (Table 

 1) but, based on analysis of variance 

 (ANOVA), this difference was not stat- 

 istically significant (P 0.264). Similarly, 

 paralarvae collected inshore tended to 

 be larger than those offshore (Table 1), 

 but this tendency also was not statis- 

 tically significant (ANOVA, P 0.610). 

 There was no obvious pattern of occur- 

 rence (number of samples) among sta- 

 tions, nor obvious patterns of changes 

 in abundance or size alongshore. 



Estuarine distribution 



Whereas 237 L. brevis were collected in 

 152 coastal samples (5% of samples), 



T 

 2.0 4.0 6 8 10.0 



DISSOLVED OXYGEN (ml/1) 



Figure 4 



Occurrence of paralarvae with respect to salinity and dissolved oxygen. (Solid 

 circles) Samples that collected Lolliguncula brevis; (open circles) samples that 

 did not. Each circle may represent more than one sample. 



