be touching each other although no measures of interanimal 

 distance were made. 



Faunal Associations 



The relationship between the three dominant invertebrates 

 was evaluated with the emphasis on the specific relationship with 

 the scallop. Figure 3 shows the number of scallops, myxicolid 

 worms and cerianthid anemones per photo frame for the three dives 

 on Fippennies Ledge. The general impression of the scientist 

 divers was that myxicolids and scallops occurred together while 

 cerianthid abundance was inversely related to scallop density. 

 The photographic record confirms this qualitative observation. 

 It is especially clear for DELTA dive 440 where the highest 

 abundance of scallops was observed (Figure 3). To quantify 

 these relationships, the species association between Placopecten 

 and Myxicola , and Placopecten and Cerianthus was analyzed using 

 2x2 contingency tables (Southward, 1968). The occurrence, co- 

 occurrence or absence of each species was noted for each 

 photograph, disregarding the actual number of individuals of each 

 species per frame, and the resulting data was analyzed for 

 departure from randomness. The data for both Myxicola and 

 Cerianthus were non-random, showing a positive association 

 between Myxicola and Placopecten (X 2 = 41.33, P<0.05, 1 d.f.) and 

 a negative association between Cerianthus and Placopecten (X^ = 

 7.66, P<0.05 1 d.f.). On Jeffreys Ledge and Platts Bank, where 

 scallop densities are much lower, the data does not support the 

 results reported above for Fippennies Ledge. On Platts Bank no 

 significant relationships were found between Placopecten and 

 either Myxicola (X 2 = 0.03) or Cerianthus (X 2 = 0.0004). On 

 Jeffreys Ledge there was no significant relationship between 

 Placopecten and Cerianthus (X 2 = 1.19) but there was a negative 

 association between Myxicola and Placopecten (X 2 = 12.03, P<0.05, 

 1 d.f.). This significant negative association is primarily the 

 result of the occurrence of Myxicola in the absence of 

 Placopecten . In an area heavily dragged for scallops, such as 

 Jeffreys Ledge, a negative association might be expected. 



Dredging Effects 



During the course of the dive on Jeffreys Ledge, areas that 

 were dredged were readily distinguishable from undredged, or at 

 least not recently dredged, bottom. The most obvious feature was 

 a change in substrate from the more organic/silty sand to a sandy 

 gravelly appearance. Occasionally, piles of rock and scallop 

 shells were observed, having obviously been emptied out of a 

 dredge once it was brought to the surface. No concurrent 

 dredging and diving took place so it is impossible to say how 

 quickly the bottom recovers from dredging activity in this area. 

 (Such a study is now under way by Dr. Fred Serchuk, National 

 Marine Fisheries Service, Woods Hole, MA USA; see also Caddy, 

 1973). On the macrofaunal level, obviously scallops are removed 

 by dredging but it appears that both Myxicola and Cerianthus are 

 capable of retracting into the sediment below the cutter bar. The 



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