Answer:
Red drums prey upon smaller fish such as anchovies and menhaden, as well as crabs and shrimp. Juveniles eat zooplankton and small invertebrates.
Step-by-step explanation:
Feeding habits, seasonal diet variation, and predator size-prey size relationships of red drum (Sciaenops ocellatus) were investigated in Galveston Bay, Texas through stomach contents analysis. A total of 598 red drums ranging from 291–763 mm in total length were collected and their stomach contents were analyzed during fall 1997 and spring 1998. The diet of red drum showed significant seasonal patterns and was dominated by white shrimp (Penaeus setiferus) during fall and gulf menhaden (Brevoortia Patronus) during spring. Blue crab (Callinectes sapidus) was an important component of red drum diets during both seasons. Significant differences existed between prey types consumed during fall and spring as the red drum diet reflected seasonal variation in prey availability. Predictive regression equations were generated to estimate the original carapace width of blue crabs from several measurements taken from carapace fragments recovered in red drum stomachs. Regressions were highly significant (r2>0.97) and increased the number of blue crabs with size information nearly threefold. Predator size-prey size relationships were determined for red drum feeding on white shrimp, gulf menhaden, and blue crab. Although regression slopes were statistically significant, prey sizes increased only slightly with increasing red drum size. Comparisons of prey sizes consumed by red drums with sizes occurring in the field indicate that red drums feed in nearshore shallow-water habitats, which serve as nursery areas for many juvenile fishes and crustaceans. Our findings demonstrate that red drums feed on several prey species of commercial and recreational value and may have important effects on estuarine community structure.