bloodworms) and small crustaceans (Sanders et al. 1962; and Dean and Ewart 

 1978). 



Habitat preferences . Bloodworms are found in both the estuarine and 

 marine systems. In Chesapeake Bay the lower salinity limit for natural 

 populations is approximately 15 ppt (Boesch 1971). 



This worm is found on unconsolidated bottoms of the subtidal zone and in the 

 flat and beach habitats of the intertidal zone. It is most abundant in mud 

 flats. 



The adult is present in the water column during spawning and at night during 

 the late fall. The water column is the medium in which eggs are fertilized. 

 During the late fall and winter individuals are carried by the movements of 

 the water column (Graham and Creaser 1978; and Dean 1978b). 



Factors of abundance . Distribution and abundance of bloodworms are 



affected by several natural factors. For instance, larvae are known to 



require temperatures under 68 °F (20 °C) for extended periods immediately after 



fertilization, and optimal salinity for the larvae was found to be 22 to 26 

 ppt (Schick 1974) . 



Predation is also a factor. For example, predation by gulls ( Larus ) and fish, 

 such as striped bass, when the bloodworms are in the water column during 

 spawning (Creaser 1973) may be significant. However, the magnitude of this 

 and other types of mortality is unknown. According to Dean (1978b), however, 

 because migrations of bloodworm occur in late fall and winter, predation 

 probably is insignificant. 



Sediment type and/or detritus content may also have some effect on the 

 populations of bloodworms. Evidence of sediment or detrital requirements is 

 incomplete. 



Sandworm (Nereis virens) 



The sandworm is a burrowing polychaete that is often one of the most abundant 

 animals in intertidal flat communities. It may reach a length of 35 inches 

 (900 mm; Pettibone 1963) and is harvested commercially for the bait worm 

 industry. It often leaves its burrow either to swim or crawl for several 

 meters on the substrate surface and then forms another burrow. Sandworms have 

 been observed migrating downstream in estuaries during ebb tides in winter 

 (Dean 1978a). 



Distribution and abundance . The range of the sandworm in North America 

 extends from Newfoundland to Virginia (MacGinitie and MacGinitie 1968) . 

 Although common in the intertidal zone of coastal and estuarine waters, the 

 sandworm also occurs subtidally down to depths of 475 feet (154 m; Gosner 

 1971). Intertidal populations are most abundant near the low water mark of 

 flats. The burrows of this species may be deep, up to 18 inches (45 cm) in 

 the sediment (Pettibone 1963). 



Population densities of up to 537 worms/m were reported on flats in 

 Wiscasset, Maine (personal communication from E. P. Creaser, Maine Department 

 of Marine Resources, Augusta, ME; April, 1978), and up to 637 worms/m 2 in the 



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