found most frequently and in greatest abundance in intertidal mud flats 

 (Larsen and Doggett 1978a). Larvae inhabit subtidal unconsolidated sediments 

 and the water column. 



Factors of abundance . Various natural factors may influence the 

 distribution and abundance of sandworms. This species is especially 

 vulnerable to predation because it often emerges from its burrow to feed. 

 Worms are an important food source for many fish (Pettibone 1963) as well as 

 rock crabs and green crabs. 



During spawning males swimming at the water surface are often preyed upon by 

 seagulls (Larus). The effect of the observed winter migration of worms (Dean 

 1978a) on the total population is unknown. However, Dean (1978) believes that 

 predation is minimal in the winter. 



Extended ice cover on mud flats sometimes causes high mortality of sandworms 

 because of oxygen depletion (Rasmussen 1973) . Laboratory experiments with the 

 sandworm indicate that this species is ordinarily extremely efficient in 

 oxygen utilization (Newell 1970). In an area of the Sheepscot estuary, which 

 is covered by ice most of the winter, relatively high abundances of sandworms 

 (347/m ) were found in samples taken in early April (Larsen and Doggett 

 1978b). This indicates that subtidal populations may not necessarily have 

 high winter mortalities. 



Human Impacts 



Harvesting may have a significant effect on the abundance of sandworms. 

 However, no data are available on fishing mortality of either sandworms or 

 bloodworms . 



Shippers, diggers, and sportf ishermen have noted a decline in the size and 

 abundance of worms in recent years (Schroeder 1978). Many worms that are 

 missed in the process of digging may be damaged or left exposed to temperature 

 extremes and predation. 



Landings (figures 12-8 and 12-9) and abundances reported by Larsen and Doggett 

 (1978 a and b) from the intertidal zone along the coast of Maine and in the 

 subtidal zone of the Sheepscot estuary (Larsen 1979) indicate that sandworms 

 are more abundant than bloodworms. 



Other factors that may potentially reduce worm abundance are shoreline 

 construction, dredging, toxic discharges or spills. Information on the 

 effects of these factors is lacking. 



Importance to Humanity 



Marine worms are the favored bait of many saltwater sportf ishermen along the 

 east coast of the United States, particularly from Long Island, NY, to 

 Chesapeake Bay. Because of the demand for worms by these fishermen, the bait 

 worm industry is the fourth most valuable fishery in Maine after lobster, 

 clams, and finfish. 



12-28 



