infaunal community in Virnstein's (1977) Chesa- 

 peake Bay experiments. Since the hogchoker 

 density used (one per 0.25 m" ) is much higher 

 than usually prevaiHng hogchoker densities, it 

 may be reasonable to conclude that the hog- 

 choker has a relatively trivial impact on benthic 

 infaunal systems as a consequence of its feeding 

 activity. This result probably indicates that hog- 

 chokers, like flounders, do not excavate the sedi- 

 ments to the degree that is characteristic of many 

 rays and skates and of the blue crab. 



As juveniles, other species of bottom-feeding, 

 predatory fishes frequently visit intertidal flats at 

 high tide. Some of these species are so generally 

 abundant in the sounds and estuaries of North 

 Carolina that their presence on the intertidal flat 

 is quite obvious. For instance, spot [Leiostomus 

 xanthurus), Atlantic croaker {Micrpogonias undu- 

 latus), silver perch (Bairdiella chrysuora),dnd pig- 

 fish [Orthopristis chrysoptera) are all abundant 

 during warm months. Because of their relatively 

 large size, they have relatively high feeding rates. 

 Virnstein (1977) measured the impact of spot on 

 the benthic infaunal community inside cages in 

 Chesapeake Bay and found that one spot per 

 0.25 m^ significantly reduced the abundance and 

 diversity of the infauna. Although this experiment 

 was carried out in a subtidal habitat, the occa- 

 sionally high abundance of juvenile spot in the 

 intertidal zone suggests that they may have a simi- 

 lar impact there. 



A few spot, Atlantic croaker, pigfish, and 

 silver perch are year-round residents of shallow 

 waters in North Carolina, but most adults of these 

 species migrate offshore to spawn in fall and win- 

 ter. All four of these species are commonly caught 

 by sport fishermen, while spot and Atlantic 

 croaker also contribute to commercial fisheries. 

 Because each species feeds, at least occasionally, 

 on intertidal flats, this habitat contributes to 

 these important fisheries to some extent. How- 

 ever, the majority of the feeding of each of these 

 species occurs outside of intertidal habitats. For 

 this reason, the truly characteristic fishes of inter- 

 tidal flats remain the baitfishes (silvcrsides, ancho- 

 vies, menhaden, killifishes, mullets, etc.), the rays 

 and skates, and the flatfishes (flounders, sole, and 

 tonguefish). If any fish species would be 

 threatened with local extinction by the elimina- 

 tion of intertidal mud and sand flats, that species 

 would come from this list. In North Carolina, 



probably all the baitfishes, rays, and flatfishes 

 would be seriously depleted by loss of intertidal 

 flat habitat. The planktivores, which benefit from 

 the increased production of phytoplankton over 

 intertidal flats, and the piscivorous (fish-eating) 

 predators would also suffer through depletion of 

 their food. 



Table 2 lists a few additional bottom-feeding, 

 predatory fishes which, upon occasion, forage in 

 the intertidal zone of estuaries, sounds, and 

 lagoons in North Carolina. Some of these species, 

 such as the lizardfish (Synodus foetens) and the 

 oyster toad {Opsanus tan), are abundant, although 

 the bulk of their feeding is undoubtedly done 

 outside of the intertidal zone. Oyster toads 

 commonly forage around hiding places in the sub- 

 tidal zone, but this foraging often carries them up 

 onto intertidal flats. Oyster toads are also known 

 to excavate pits while feeding in the intertidal 

 zone. Occasionally, an oyster toad can be found 

 stranded in such a pit at low tide. 



4.4 NON-RESIDENT FISHES INDIRECTLY 

 DEPENDENT UPON INTERTIDAL FLATS 



The fishes listed in Table 3 are only occasion- 

 ally found over intertidal flats, but ordinarily con- 

 sume some prey that have fed in intertidal environ- 

 ments. Most of these species are large, very 

 mobile predators and fall into the fourth trophic 

 category: consumers of fish and large epibenthic 

 invertebrates. As such, these species tend to feed 

 on a higher trophic level than those species which 

 forage directly on the intertidal flat. Many of 

 these larger predators, especially the sharks, re- 

 main in deeper water during the day and only 

 approach the shallows during the cooler tempera- 

 tures of night. Because these species are so large 

 and mobile, they are rarely netted in otter trawls 

 or seines, so that their abundance and importance 

 in coastal systems are largely unknown. 



Several of these larger predators are valuable 

 to either commercial or sport fisheries in North 

 Carolina. The weakfish {Cynoscion regalis) is 

 probably the most important of these. Although 

 less abundant, the spotted seatrout (C. nebulosus) 

 and small red drum or "puppy drum" {Sciaenops 

 ocellata) are prized game fishes in the sounds of 

 North Carolina. The bluefish {Pomatumus salta- 

 trix) is abundant and contributes greatly to the 



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