104 



NOAA Technical Report NMFS 140 



higher average densities were found in Nova Scotia, 

 Southern New England, and the Southern New En- 

 gland Slope. The lowest density (1.2/ni 2 ) was in the 

 Georges Slope area. 



Differences in average biomass were also compara- 

 tively small among the six geographic areas (Table 8; 

 Fig. 82). Largest average biomass (1.83 g/m L> ) occurred 

 in the Southern New England Slope area; the smallest 

 (0.37 g/m~) was in the Gulf of Maine. 



Individual sipunculids averaged approximately 0.1 g 

 in weight in all areas except Georges Slope, where their 



average weight was nearly forty times greater, 4 g per 

 individual. 



Frequency of occurrence of sipunculids was moder- 

 ate to moderately low. They were present in 13 to 42% 

 of the samples (Table 10). Highest frequency of occur- 

 rence was in the Nova Scotia area and lowest was on 

 Georges Bank. 



Bathymetric Distribution 



Sipunculids were taken at depths ranging from 16 to 

 3,975 m. They were most common at moderate depths, 

 25 to 500 m, where they averaged about 6 to 

 8 individuals/ m 2 (Table 11; Fig. 83). In both 

 shallower and deeper zones they averaged 

 nearly 1 or 2/m L . 



The relation between biomass of sipun- 

 culids and water depth was substantially dif- 

 ferent from that of numerical density. Bio- 

 mass was much greater (averaging about 1 to 

 4 g/m 2 ) on the middle and lower portions of 

 the continental slope (500 to 2,000 m) than 

 it was on the continental shelf and continen- 

 tal rise (Table 13, Fig. 83). Also, sipunculids 

 formed 10 to 26% of the total benthic biom- 

 ass at these depths, compared with less than 

 1% for the shallower zones and 5% for the 

 continental rise (Table 14). 



The percentage of samples containing 

 sipunculids was lowest (3 to 13%) at depths 

 less than 50 m (Table 15). At depths greater 



