FISHERY BULLETIN: VOL 85, NO. 4 



egory. This was also observed in the present in- 

 vestigation. Individual stomachs from spot cap- 

 tured in the same sample were often found to 

 contain thousands of harpacticoid copepods or 

 were completely distended by half a dozen nereid 

 polychaetes. Such observations reinforce the no- 

 tion of opportunism and feeding activities related 

 to the concentration and availability of prey. 



Spot, as well as other estuarine sciaenids, 

 undergo distinct ontogenetic changes in feeding 

 mechanisms with increasing size (Chao 1976; 

 Chao and Musick 1977; Govoni 1981). Postlarvae 

 and small juveniles are characterized by large 

 eyes and a terminal mouth. They prey on mainly 

 pelagic calanoid copepods and other small plank- 

 ton (Townsend 1956; Peters and Kjelson 1975; 

 Kjelson et al. 1975; present study). April was an 

 outlier in the seasonal dendrograms of Figures 6 

 and 7 because the majority of spot at that time 

 were in the smallest size class in Figure 8 and fed 

 on mainly calanoid copepods. Although Thayer et 

 al. (1974) concluded that food for meroplanktonic 

 life stages of estuarine fishes may be limiting, we 

 observed no differences in feeding success be- 

 tween spot consuming plankton and those eating 

 benthos. 



At about 20 mm SL, spot become more benthic 

 oriented, feeding on various epifauna and infauna 

 (Livingston 1982; present study). Sheridan (1979) 

 also noted a distinction in prey utilization of 

 smaller spot (20-29 mm). In the habitats of Flor- 

 ida's Apalachicola Bay, however, he noted that 

 individuals in this size class consumed more in- 

 sect larvae and polychaetes than copepods. His 

 larger size classes utilized more bivalves. The dif- 

 ference between his observations and those in our 

 study may simply be due to the difference in prey 

 availability at the various locations. It should 

 also be noted that other studies on the food habits 

 of spot failed to recognize any size-related differ- 

 ences (Roelofs 1954; Darnell 1958; Stickney et al. 

 1975; Chao and Musick 1977; Hodson et al. 1981). 

 This is possibly due to the selective nature of the 

 gear used. Large seines and trawls fail to sample 

 small fish (Chao and Musick 1977), and block net- 

 ting in the high marsh may select against large 

 fish (Hodson et al. 1981). 



The dominant prey items consumed by spot in 

 each habitat, and the basis for intercreek and 

 shoal versus creek differences observed during 

 our study, are partly explained by distribution 

 patterns of macrobenthic invertebrates reported 

 by Boesch (1977) for the York River, VA. Al- 

 though that study was conducted several years 



before ours, and were restricted to the river 

 shoals and channels, there is a close parallel be- 

 tween the patterns Boesch described and the diet 

 of spot from similar localities within the York 

 River. Boesch described a group of species that 

 were "characteristically abundant in salinities of 

 10-20%( throughout the Chesapeake Bay system 

 but were not usually as abundant in higher salin- 

 ities except in shallow water habitats or following 

 disturbances." He referred to them as euryhaline 

 opportunists that were important dietary con- 

 stituents of spot at both creeks in our study. 



Most of the identifiable polychaetes encoun- 

 tered in spot stomachs were from this group, e.g., 

 Nereis succinea , Eteone heteropoda , and Parapri- 

 onspio pinnata (Spionidae). The cumacean Leu- 

 con americanus also belongs to this group and 

 together with the amphipod Monoculodes ed- 

 wardsi was consumed in large quantities by spot 

 on Goalders shoal (Fig. 8). Monoculodes is a mem- 

 ber of the group Boesch described as estuarine 

 endemics, which are most frequent in meso- 

 oligohaline areas. Down-estuary at Blevins 

 Creek, the maldanid polychaetes, especially Cly- 

 menella torquata, figured prominently in spot 

 diets and were determined to be most abundant in 

 that vicinity by Boesch. 



In another study, Boesch (1973) examined mac- 

 robenthic distributions as related to sediment 

 composition and seasonality in Hampton Roads, 

 VA. Those results give further insight to prey 

 availability for the habitats and time periods de- 

 scribed in the present study. Boesch (1973) found 

 Eteone heteropoda more common in May and rare 

 in August, but distributed over all sediment types 

 in the areas of lower salinity. This species was 

 commonly consumed by spot at Blevins Creek in 

 May, June, and July (Fig. 7). Another polychaete, 

 Polydora ligni, was common in stomachs from 

 Blevins Creek only in April, and Boesch (1973) 

 noted it was more abundant in the estuary be- 

 tween February and May. Clymenella torquata, 

 also consumed at Blevins Creek, was less abun- 

 dant seasonally but showed a preference for 

 muddy-sand sites. This species was a dominant 

 component in the diet of spot at the downstream 

 and shoal stations, both of which had higher pro- 

 portions of sand compared to the upstream sta- 

 tion. Two polychaetes, Nereis succinea and Para- 

 prionospio pinnata (Spionidae), were found by 

 Boesch (1973) in sand-mud and mud-sand sedi- 

 ments, respectively, which generally character- 

 ized the Goalders upstream and downstream sub- 

 strates, respectively (Table 2). Thus, it is likely 



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