recently dredged areas suggesting that they simply retract into 

 their burrows to avoid the dredge. As a consequence, removal of 

 the scallops can occur without a negative impact on the two other 

 dominant invertebrates. 



INTRODUCTION 



In a report on the sea scallop, Placopecten magellanicus , 

 the New England Fisheries Management Council (1981) proclaimed 

 that the entire Northwest Atlantic continental shelf of less than 

 100 meters depth might be suitable scallop habitat. While this 

 statement may or may not be true, it emphasizes the point that 

 very little is actually known about the ecology of this species. 

 For an animal that is heavily fished, indeed possibly overfished, 

 (Anderson, 1984), this lack of information compounds the problems 

 facing resource managers. Knowledge of basic scallop biology is 

 critical for predicting the resilience of the stocks to high 

 fishing pressure. For the Gulf of Maine, this is particularly 

 true because the catches since 1980 have been the highest on 

 record (Anderson 1984). The following account is a comparative 

 study of three offshore scallop grounds in the Gulf of Maine. 



METHODS 



This work was initiated in the summer of 1984 as a 3 to 5 

 year study of various offshore scallop grounds in the Gulf of 

 Maine (Figure 1). Three different manned submersibles have been 

 utilized to conduct quantitative photographic transects and make 

 videotape recordings and general observations on three offshore 

 banks. In this preliminary report, data from six out of a total 

 of eight dives is described. One dive was made in 1984 on Platts 

 Bank (Figure 2) using the submersible Mermaid II. In 1986 five 

 dives were made using the submersible Delta . Two dives were on 

 Jeffreys Ledge and three on Fippennies Ledge (Figure 2). In 1985 

 two dives were also made on Jeffreys Ledge using the Johnson Sea 

 Link J. but this information is not included here. In 1987 the 

 Fippennies Ledge study site was revisited using the Delta 

 submersible system and a total of six transects were completed. 

 Analysis of these most recent dives is, however, not yet complete 

 and the data is not included in this report. 



Although each submersible system is unique, the transect 

 technique was similar throughout the study. Generally, the 

 submersible was launched at a preselected dive site and once on 

 the bottom its exact location determined by ship to sub sonar and 

 Loran C. Throughout the dive the sub and support ship were in 

 frequent communication and location fixes were taken at regular 

 (10 to 15 minute) intervals, whenever the diver noted a unique 

 bottom feature, or when the submersible changed direction. When 

 the submersible was stationary, during a location fix, the video 

 camera was used to document bottom features; also, when the 

 submersible was traversing slowly over the bottom video pictures 

 were often taken. Random still color photographs, 35 mm, were 

 taken at 10 to 15 second intervals over the entire transect. 



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