Grover: Feeding habits of pelagic summer flounder larvae 
251 
Table 1 
Feeding incidence and number of prey ingested by summer flounder, P. dentatus, larvae by time block, habitat, and larval stage. 
OC = oceanic, ES = estuarine, PF = preflexion, FLX = flexion, PM = premetamorphic, and M = metamorphic (oceanic). Estuarine 
metamorphic stages are as defined by Keefe and Able (1993). Numeric data exclude copepod eggs that appeared to have been 
ingested incidentally by metamorphic larvae. 
Standard length (mm) 
Habitat 
type 
No. larvae 
examined 
mean 
SD 
range 
No. larvae 
with food 
Percentage 
feeding 
Total no. 
food items 
No. food items per 
feeding larvae 
Time block (h) 
0000-0159 
OC 
67 
3.8 
1.22 
2. 3-7. 5 
11 
16.4 
40 
3.6 
ES 
15 
11.4 
1.29 
8.6-13.4 
1 
6.7 
1 
1.0 
0200-0359 
OC 
18 
4.5 
1.04 
3. 4-6. 7 
2 
11.1 
3 
1.5 
ES 
11 
12.3 
1.91 
8.8-14.6 
1 
9.1 
1 
1.0 
0400-0559 
OC 
60 
4.8 
1.35 
2. 2-7. 2 
5 
8.3 
7 
1.4 
ES 
11 
11.3 
0.97 
9.5-12.9 
2 
18.2 
3 
1.5 
0600-0759 
OC 
44 
4.3 
1.39 
2.6-7. 6 
24 
54.5 
104 
4.3 
ES 
2 
10.3 
0.44 
10.0-10.6 
0 
0.0 
0 
0.0 
0800-0959 
OC 
10 
4.1 
0.76 
3. 2-5. 3 
10 
100.0 
46 
4.6 
1000-1159 
OC 
33 
3.8 
0.96 
2. 7-5.8 
27 
81.8 
107 
4.0 
1200-1359 
OC 
39 
3.7 
1.23 
2. 1-8.0 
38 
97.4 
259 
6.8 
1400-1559 
OC 
41 
3.6 
1.16 
2. 1-8.3 
36 
87.8 
256 
7.1 
1600-1759 
OC 
67 
3.6 
0.70 
2. 6-6. 2 
47 
70.1 
168 
3.6 
1800-1959 
OC 
32 
3.8 
1.12 
1.9-7. 9 
27 
84.4 
106 
3.9 
ES 
36 
12.4 
1.62 
8.8-14.5 
5 
13.9 
13 
2.6 
2000-2159 
OC 
60 
3.9 
1.37 
2. 3-9.0 
42 
70.0 
258 
6.1 
ES 
39 
11.9 
1.48 
8.1-13.9 
5 
12.8 
12 
2.4 
2200-2359 
OC 
50 
4.1 
1.25 
2. 1-8.3 
11 
22.0 
31 
2.8 
ES 
5 
11.3 
1.76 
8.8-13.5 
1 
20.0 
2 
2.0 
Larval stage 
PF 
OC 
439 
3.6 
0.85 
1.9-6. 9 
250 
56.9 
1276 
5.1 
FLX 
OC 
65 
5.6 
0.75 
3. 7-7. 2 
22 
33.8 
86 
3.9 
PM 
OC 
9 
6.6 
0.92 
4.8-7. 6 
4 
44.4 
17 
4.3 
M 
OC 
8 
7.7 
0.97 
5. 8-9.0 
3 
37.5 
6 
2.0 
G 
ES 
47 
11.9 
1.74 
8.1-14.4 
9 
19.1 
19 
2.1 
H- 
ES 
34 
12.0 
1.51 
8.8-14.6 
3 
8.8 
7 
2.3 
H 
ES 
35 
11.8 
1.35 
8.8-14.5 
1 
2.9 
2 
2.0 
H+ 
ES 
1 
12.6 
12.6 
1 
100.0 
1 
1.0 
I 
ES 
2 
13.3 
0.71 
12.8-13.8 
1 
50.0 
3 
3.0 
Immature copepodites composed the bulk of the 
diet (61.4% Vol, 37.3% IRI; Table 2) of PF larvae. 
Copepod nauplii, the second most important prey, 
composed 20.0% (N and IRI) of the diet. Tintinnids, 
despite being the most abundantly ingested prey 
(28.7% N), ranked third in importance at 19.3% (IRI). 
Bivalve larvae and copepod eggs were the only other 
prey that accounted for >1% of the diet, and together 
they composed 21.7% (IRI). 
The size of ingested prey was directly related to 
larval size. Only PF larvae, the smallest larvae, abun- 
dantly ingested small prey, i.e. tintinnids, copepod 
nauplii, copepod eggs, and bivalve larvae. Diatoms 
and dinoflagellates were also occasionally ingested 
(4.4% FO), although both were of such minor impor- 
tance in the total diet that they were pooled into the 
“other” prey category. The mean number of prey 
found in the guts of PF larvae was 5.1 (SD=4.47, 
range: 1-25). For PF larvae, the ingestion of cope- 
pod eggs and invertebrate eggs was clearly indepen- 
dent of the ingestion of berried females. Visual cues 
of prey may be important for feeding larvae because 
grains of sand that visually “mimicked” bivalve lar- 
vae, in size, shape, and color, were ingested along 
with bivalve larvae by 4.4% of PF larvae. 
Diet of flexion fFLX) larvae 
A total of 65 FLX specimens were represented in this 
study: 33.8% contained recognizable prey, and 66.2% 
had empty guts. Lengths at the time of examination 
ranged from 3.7 to 7.2 mm SL (Table 1). 
Immature copepodites dominated the diet of FLX 
larvae, regardless of method of analysis (Table 3). 
