Stellwagen Bank Final EIS and Management Plan 



Page 64 



extraction on herring in the Gulf of Finland 

 (Oulasvirta and Lehtonen, 1988), while results did 

 not indicate that Baltic herring were affected by the 

 mining operation, the catch in a trapnet set nearby 

 was significantly reduced over that of years previous 

 to the operation. 



Some of the direct impacts to organisms that live 

 on or in the sediment can be mitigated through 

 various operational practices, such as avoiding 

 overlap of dredging paths. However, as there are 

 increased costs generally associated with such 

 practices, and comphance can be difficult to ensure, 

 rehance upon operational practices as a mitigating 

 factor can be of limited value. 



Data on potential effects of offshore mining on 

 marine mammals are almost nonexistent. A recent 

 study associated with locating a dredged material 

 disposal site in Cape Cod Bay (Battelle, 1987) 

 stated that evidence available on suspended 

 sediments indicated that elevated levels would have 

 no effect on whales. This conclusion was based on 

 the speculation that whales often live in turbid 

 environments (inshore waters during winter months, 

 or offshore of glaciers); and certain species are 

 known to feed on organisms in or on the surface of 

 the sediment. However, secondary effects may be 

 significantly more important than direct impacts. 

 Bowhead and beluga whales have been observed 

 altering their swimming patterns within 2.4 miles of 

 a dredging operation, a change in behavior thought 

 to be associated with the noise generated by the 

 dredging operation (DOI, 1983b, reported in MMS, 

 1987). Similar effects also have been observed in 

 grey whales off the California coast (MMS, 1987). 



Impacts to principal prey species of marine 

 mammals also may be important. Both zooplankton 

 and phytoplankton can be affected by exposure to 

 elevated suspended sediment (MMS, 1987), possibly 

 causing some secondary impacts to marine mammal 

 predators. If fish actively avoid dredging plumes, 

 whales in the area may have to exert more effort in 

 feeding or other behavioral changes. The available 

 information presently is inadequate to allow any 

 conclusions to be drawn about this issue, beyond 

 suggesting that a potential for adverse impacts 

 exists. 



There is additionally some concern about 

 physical effects on the Bank feature resulting from 

 a substantial mining operation. Stellwagen Bank is 

 biologically productive because the Bank feature 

 causes upwelling to occur, bringing nutrient-rich 

 waters to the surface. Any change in the physical 

 characteristics of the Bank could alter the pattern of 

 upwelling. Even small alterations in the 

 characteristics of the circulation and upwelling could 

 have profound effects on the biology of the Bank. 

 In addition, there is some indication that the Bank 

 feature is very important in propagating internal 

 waves in Massachusetts Bay (Gardner 1990). 

 Internal waves seem to be important in affecting 

 both the Bay's general circulation, and its primary 

 and secondsuy production in surface waters. Any 

 change in the Bank feature caused by a mining 

 operation could affect the wave propagation 

 properties of the Bank. However, further 

 investigation and analysis are necessary to develop 

 a better understanding of the relationship between 

 the Bank and Massachusetts Bay. 



8. Ocean Disposal Activities 



a. General Disposal Activities 



Between the 1940's and the 1970's, numerous 

 offshore areas throughout Massachusetts Bay were 

 used for the disposal of a variety of industrial waste 

 products (including canisters, construction debris, 

 dereUct vessels, and radioactive waste). These 

 activities were largely unregulated and unrecorded. 



Disposal of low-level radioactive waste material 

 was permitted at foiu- areas within Massachusetts 

 Bay between 1953 and 1959, the most frequently- 

 used site being centered at 42'26.8'N and 

 70*35.0'W. Such low-level wastes were normally 

 generated by academic, commercial, and medical 

 institution sources (EPA 1980). Some radioactive 

 wastes were also disposed at this site during the 

 period between 1946 and 1953; however, previous to 

 1952 disposal records were not kept. Thus, specific 

 description of disposed materials has not as yet 

 been possible (EPA, 1984). 



In 1963, the U.S. Coast Guard deployed disposal 

 marker "A" buoy in the vicinity of the present 

 Massachusetts Bay Disposal Site (42°26.8'N X 



