Lopez-Rasgado and Herzka: Assessment of habitat quality for juvenile Para/ichthys cahfornicus 
355 
Figure 8 
Percentage of (A) wild-caught and (B) caged juvenile California halibut (Para- 
lichthys californicus) with different levels of gut fullness. Sampling was performed 
in the outer, central, and inner sections of Punta Banda Estuary between October 
2005 and October 2006. Asterisks represent lost cages. 
Regurgitation of gut contents during trawling may par- 
tially explain the high incidence of empty stomachs in 
their studies and ours. However, Plummer et al. (1983) 
did not find significant diel and spatial differences in 
gut fullness levels. We have no way of correcting for 
the potential effect of regurgitation without a full study 
designed specifically for that purpose. Nevertheless, we 
find it likely that if regurgitation is frequent in juve- 
nile California halibut, our data are likely to be biased 
systematically. 
Seasonal patterns in gut fullness levels were evi- 
dent: there was a high (up to 55%) percentage of empty 
stomachs in all sections of the estuary during the 
late fall and winter, when temperatures were low- 
est (~14-18°C). During the spring and summer, when 
temperatures were substantially higher (18-25°C), 
the incidence of empty stomachs was substantially 
lower (10-40%, except for the outer estuary in March). 
Our qualitative observation that feeding levels are 
positively related to temperature is consistent with 
Madon’s (2002) laboratory results; he observed an 
increase in food consumption and metabolic rates at 
higher temperature. Further, somatic growth rates 
of juveniles in his experimental treatments (14°, 20°, 
25° and 28°C) did not differ significantly, suggesting 
that higher food consumption is a response to higher 
metabolic demand. 
In contrast, qualitative comparison of the months 
and sections of the estuary with the highest otolith 
growth (central and inner sections October 2004, 
outer section January 2005 and outer and inner sec- 
tions May 2005) with the proportion of individuals 
that exhibited evidence of feeding did not show a 
consistent relationship. Low growth rates (Septem- 
