FISHERY BULLETIN: VOL. 75, NO. 4 



TABLE 13. — Stomach contents of northern kingfish, Menticir- 

 rhus saxatilis, from different estuarine areas along U.S. Atlantic 

 coast. 



found that harpacticoid copepods were the main 

 food for juvenile L. xanthurus and that seasonal 

 variations in diet were slight. Organic detritus 

 and unidentified remains were also common in 

 stomachs (Table 14). 



Food Partition 



To compare the feeding habits of the juveniles of 

 the six sciaenid species, a chart (Figure 29) has 

 been prepared for the six food groups defined pre- 

 viously. The main food group of Larimus fasciatus 

 was mostly planktonic and the primary food 

 species was Neomysis americana. Cynoscion re- 

 galis and B. chrysoura fed mainly on fishes and 

 macrozooplankton; the primary food species were 

 Anchoa mite hi Hi and N. americana, respectively. 

 Micropogonias undulatus fed on a wide variety of 

 food including all six food groups, with the domin- 

 ant food organisms being N. americana and Nereis 

 succinea. Menticirrhus saxatilis fed mainly on 

 macrozooplankton and epibenthos, with the pri- 

 mary food organisms being N. americana and 

 polychaetes. Leiostomus xanthurus fed on a wide 

 variety of food including five food groups. The 

 dominant food organisms were Pectinaria gouldii 

 and other polychaetes. 



Neomysis americana was very abundant and 

 available to all species of sciaenids in the study 



area. This shrimp migrates vertically in response 

 to change in ambient light (Herman 1962). 

 Neomysis americana is negatively phototactic. In 

 shallow turbid water (as in the study area) during 

 daylight it might concentrate near the bottom in 

 the darkest sector of the vertical light gradient 

 (Stickney et al. 1975). Because of the abundance 

 and availability of N. americana, the other prey 

 items should provide a better indication of feeding 

 specialization. As has been repeatedly shown (Ta- 

 bles 10-14), most fishes were sufficiently oppor- 

 tunistic in their food habits to take advantage of 

 extremely abundant prey species. All the fishes in 

 the present study were sampled by bottom trawl 

 during the daytime. Therefore, both prey and pred- 

 ators probably were dwelling close to the bottom. 

 Polychaetes were a major food resource for the 

 bottom feeders (Tables 12-14), Micropogonias un- 

 dulatus, L. xanthurus, and Menticirrhus saxatilis. 

 But Micropogonias undulatus fed more on the 

 "crawling" species of worms (Table 12) such as 

 Nereis and Nephthys (Barnes 1968) and L. xan- 

 thurus fed more on "tubiculous" or "burrowing" 

 species of worms (Table 14), such as Pectinaria and 

 Amphitrite. This is contradictory to the findings of 

 Roelofs ( 1954) and Stickney et al. (1975). Observa- 

 tions of the feeding behavior of these two species in 

 aquarium generally agreed with Roelofs (1954). 

 But L. xanthurus seemed to "dive" into the bottom 

 sand much more often than M. undulatus, and the 

 depth of the dives by L. xanthurus was not shal- 

 lower than M. undulatus as stated by Roelofs 

 (1954). 



Correlation of Feeding Structures 

 and Food Habits 



Larimus fasciatus and C. regalis have oblique 

 mouths (Figure 20A, B) and their upper jaws are 

 slightly or not protrusible (Figure 21A, B). These 

 features allow them to feed anteriorly and dorsally 

 to the longitudinal axis of their bodies along their 

 swimming course. Their mouths open as the lower 

 jaws drop anteroventrally and the distal ends of 

 the premaxillae move forward (Figure 20A', B'). 

 The mouth openings of L. fasciatus and C. regalis 

 are relatively larger than in the other species 

 studied (Table 5). The anterior views of their 

 mouths (Figure 20a, a', b, b') show that the upper 

 jaws (premaxillae) are longer or equal to the lower 

 jaws (dentaries). Although both of them feed "an- 

 terodorsally" and pelagically, they did show dif- 

 ferences in diet (Figure 29). The following mor- 



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