extent of dredging induced mortality on these sessile inverte- 

 brates could not be determined from our work although such 

 mortality may be negligible while the fishing mortality on 

 scallops can be substantial. The impact of dredging on the 

 smaller invertebrates could not be assessed in this study but it 

 may be significant if the change in substrate we observed in a 

 dredged area persists. 



DISCUSSION 



There are a number of estimates of sea scallop densities 

 available in the scientific literature (e.g., Table 1). 



Table 1. Mean density estimates for Placopecten magellanicus 

 from this study and scientific literature. 



Location 



Fippennies Ledge 

 Fippennies Ledge 



Jeffreys Ledge 

 Jeffreys Ledge 



Platts Bank 

 Digby, Nova Scotia 



N. Georges Bank 

 Georges Bank 



Gulf of St. Lawrence 

 East Newfoundland 



West Newfoundland 



Density per m 



Authority 



Throughout its geographic range scallop density on the 

 grounds generally ranges from a mean of 0.1 to <10 ani 

 square meter. The only exception to this is for spat 

 on Georges Bank where a maximum density of 123 m~ z was 

 (Larsen and Lee, 1978). One interesting aspect of the 

 mean densities from this study is the close agreement 

 estimates calculated from the work of Serchuk and Wigl 

 They report data from a scallop research vessel survey 

 in 1984, using a commercial dredge, throughout the U.S 

 Atlantic. The Gulf of Maine sampling was concentrated 

 Jeffreys and Fippennies Ledges; our submersible study 

 their highest scallop density stations. Although the 

 were temporally separated by several years the dredge 

 for greater than 90% of the scallop population observe 

 submersible. Such a comparison has to be viewed with 

 not only because of the time difference but also becau 



various 

 mals per 

 densities 



reported 



reported 

 with the 

 ey (1984). 



conducted 

 northwest 



on 

 centered on 

 two studies 

 accounted 

 d with a 

 reservation 

 se scallop 



250 



