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Fishery Bulletin 96(2), 1998 
stages F- through I (Keefe and Able, 1993), based on 
degree of eye migration. 
Incidence of feeding and gut fullness were also 
examined, as a function of 2-h time blocks. Gut full- 
ness (F) was recorded as 0 = empty, 1 = 1-25%, 2 = 
26-50%, 3 = 51-75%, and 4 = 76-100% full. Incidence 
of feeding was recorded as the percent frequency of lar- 
vae that had prey in their guts (i.e. F > 0), in relation to 
the total number of specimens examined in a time block. 
A total of 550 oceanic larvae were examined. Of 
these, 18 were excluded from analysis because large 
portions of their guts were missing, and 11 were ex- 
cluded because their primitive condition likely impaired 
their ability to ingest prey (Blaxter, 1986; Gadomski 2 ). 
Primitive characteristics included presence of yolk sac, 
absence of eye pigment, and undeveloped mouth. Evi- 
dence of prey ingestion was lacking in the 29 excluded 
larvae. This study was based on 521 oceanic larvae that 
were deemed to be functionally intact. 
A second series of collections were examined to 
determine the feeding ecology of summer flounder 
larvae as they enter an estuarine nursery habitat. 
Metamorphic larvae were collected from plankton 
entering the Great Bay-Little Egg Harbor (New Jer- 
sey) estuary (Fig. 2) during fall, winter, and spring 
from 1989 to 1995. Most estuarine specimens (71.4%) 
were collected between November and January. The 
remainder were collected between February and 
June, and in October. Stationary plankton nets (1-m 
diameter, 1.0-mm mesh) were set for 30 min, at the 
surface and just off the bottom, on nocturnal flood 
tides, from a bridge across Little Sheepshead Creek 
(Szedlmayer et al., 1992; Keefe and Able, 1993). This 
site is characterized by Atlantic Ocean water on flood 
tides (Charlesworth, 1968, cited in Szedlmayer et al., 
1992); thus larvae were likely captured as they en- 
tered the estuary from the ocean, or soon after. 
Estuarine specimens were preserved in 95% etha- 
nol, and they remained in ethanol until their examina- 
tion. Specimens were processed as above. Because all 
estuarine specimens were metamorphic ( ME ), morpho- 
logical stages were recorded in terms of Keefe and Abie’s 
(1993) metamorphic stages: F- through I. The estua- 
rine portion of this study was based on 119 specimens. 
Results 
Preflexion (PF) larvae were the dominant morpho- 
logical stage in oceanic collections, accounting for 
84.3% of the specimens (Table 1). Later morphologi- 
2 Gadomski, D. 1995. Columbia River Research Laboratory, 
National Biological Service, 5501 A Cook-Underwood Road, Cook, 
WA 98605. Personal commun. 
Figure 2 
Location of the estuarine site in Little Sheepshead Creek, New 
Jersey, where metamorphic summer flounder, P. dentatus, were 
collected. (Figure by K. W. Able, Rutgers University.) 
cal stages were progressively rarer, with flexion (FLX) 
larvae accounting for 12.5%, postflexion, premeta- 
morphic (PM) larvae accounting for 1.7%, and meta- 
morphic (M) larvae accounting for 1.5% of the oce- 
anic specimens in this study. Although greater than 
33% of the larvae in each morphological stage con- 
tained prey in their guts, stages PM and M were com- 
bined for dietary analyses because of their small rep- 
resentation in these collections and similarity in diet. 
Larval lengths that were recorded at the time 
samples were sorted (usually within 12 months of 
collection) were compared with lengths at the time 
of examination in order to estimate shrinkage. Com- 
parisons based on 329 specimens defined mean 
shrinkage as 13.7% (SD=5.83). 
Diet of preflexion (PFJ larvae 
The dominant stage in this study, PF, was represented 
by a total of 439 specimens: 56.9% contained recog- 
nizable prey, and 43.1% had empty guts. Lengths at 
the time of examination ranged from 1.9 to 6.9 mm 
SL (Table 1). 
