Crabtree et al.: Feeding habits of Albula vulpes 
765 
Table 8 
Breakdown into the most important prey groups of the 
mean dissimilarity between stomach contents (percent 
number) of bonefish, Albula vulpes (480-699 mm FL), 
caught on the ocean side of the Florida Keys (/r =39 ) and 
throw-trap samples (n= 54) from the ocean side of the 
Florida Keys. Prey groups are listed in order of decreasing 
contribution to the overall dissimilarity between the two 
samples. Taxa proportionally more important in the diet 
of bonefish than suggested by their proportional abundance 
in throw-trap samples are shown with bold type. The low 
values of 5- /SD( 8 ; ) suggest that the data were variable and 
that no taxa were reliable discriminators of either sample 
source. Symbols are explained in the legend of Table 4. 
Species 
5/SD(8,) 
5, % 
Cum 8- % 
Alpheidae 
10.58 
1.31 
13.87 
13.87 
Xanthidae 
Periclimenes 
7.89 
1.13 
10.35 
24.23 
americanus 
6.83 
0.93 
8.96 
33.19 
Thor spp. 
6.11 
0.97 
8.02 
41.20 
P. duorarum 
5.95 
0.88 
7.81 
49.01 
O. beta 
4.61 
0.80 
6.05 
55.06 
1989a, 1989b). Our sampling effort was over a large 
and diverse area, and this limited our ability to re- 
solve area-specific differences in bonefish diet. Some 
Florida Bay areas that we sampled were near passes 
leading to ocean-side flats and may have more closely 
resembled ocean-side areas than some of the more 
remote areas in Florida Bay where we occassionally 
caught bonefish. Larger sample sizes, more inten- 
sive sampling of specific areas along with site-spe- 
cific descriptions of habitat types, and sampling of 
prey availability concurrent with bonefish collections 
are needed to better describe spatial variation in the 
diet of Keys bonefish. 
Comparisons of the stomach contents of bonefish 
collected in Florida Bay and ocean-side areas as well 
as seasonal comparisons were complicated by the 
variable monthly sample sizes from the two areas. 
We excluded over half of the bonefish in our sample 
from our area comparisons because seasonal sample 
sizes from the two areas were greatly unequal. The 
variable sample sizes from the two areas reflect gen- 
eral seasonal trends in bonefish availability in the 
two areas. Bonefish are typically most abundant in 
Florida Bay during summer and fall. Winter cold 
fronts tend to reduce Florida Bay temperatures more 
than ocean-side temperatures (Hudson et al., 1976; 
Roberts et al., 1982; Chiappone, 1996), and many 
productive summer-fall fishing areas in Florida Bay 
rarely hold bonefish during winter and spring be- 
cause bonefish move to ocean-side areas with more 
moderate temperatures and closer proximity to deep 
Table 9 
Breakdown into the most important prey groups of the 
mean dissimilarity between stomach contents (percent 
number) of bonefish, Albula vulpes (480-699 mm FL), 
caught in Florida Bay (n= 45) and throw-trap samples 
(tj= 30) from Florida Bay (Matheson et al. 1 ). Prey groups 
are listed in order of decreasing contribution to the overall 
dissimilarity between the two samples. Taxa that are likely 
to be reliable discriminators of the two samples are indi- 
cated by ** in the 5/SD(5 ; ) column. Taxa proportionally 
more important in the diet of bonefish than suggested by 
their proportional abundance in throw-trap samples are 
shown with bold type. Symbols are explained in the leg- 
end of Table 4. 
Species 5 [ S/SDtS,) 8 | % Cum 8 | % 
Thor spp. 
18.13 
1.97** 
23.03 
23.03 
Xanthidae 
9.63 
1.17 
12.24 
35.27 
Alpheidae 
7.61 
1.23 
9.67 
44.94 
O. beta 
7.51 
1.15 
9.55 
54.49 
P. duorarum 
Hippolyte 
5.17 
0.81 
6.57 
61.06 
zostericola 
Periclimenes 
5.00 
1.65** 
6.36 
67.42 
americanus 
4.55 
1.85** 
5.78 
73.20 
Callinectes spp. 
Gobiosoma 
3.23 
0.48 
4.10 
77.30 
robustum 
3.03 
1.98** 
3.85 
81.15 
water. Thus, most of our Florida Bay bonefish were 
captured during summer and fall, and most ocean- 
side bonefish were caught during winter and spring. 
Seagrass die-offs have recently been documented 
in Florida Bay (Robblee et al., 1991; Carlson et al., 
1994; Durako, 1994; Butler et al., 1995). Anecdotal 
evidence suggests that changes in the Everglades 
ecosystem have caused a decline in the quality of Fish- 
ing in Florida Bay and the waters of the Florida Keys 
(Chiappone and Sulka, 1996). If changes in the 
benthic epifauna and infauna have resulted from the 
seagrass die-off, these changes could potentially af- 
fect feeding and occurrence of bonefish in Florida Bay. 
Data on the species composition and abundance of 
epifaunal crustaceans and fishes collected subse- 
quent to the sea grass die-off and the studies of 
Sogard et al. (1987, 1989) and Holmquist et al. 
(1989a, 1989b) prior to the seagrass die-off suggest 
little evidence of declines in populations of impor- 
tant bonefish prey species (Matheson et al. 1 ). One 
significant change reported by Matheson et al. 1 was 
an increase in the abundance of O. beta in some ar- 
eas of Florida Bay since the 1980s. Whether the in- 
creased abundance of O. beta compared to that found 
in previous studies accounts for its greater promi- 
nence in stomachs of the bonefish we sampled is 
unknown. 
