inversely proportional to the prevailing 

 rate of water exchange. With the dou- 

 bling of flushing time in the high pool, 

 conditions for retention of the pelagic 

 larvae are seen to be greatly improved. 

 The less rapid passage of soluble 

 nutrients carried into Passamaquoddy 



Bay by fresh-water runoff should en- 

 hance the supply of planktonic food for 

 juvenile and adult scallops. A doubling 

 of the sea scallop catch in the high 

 pool is predicted, with an annual in- 

 crease in the fishermen's earnings of 

 about $700 {table 6). 



Tatle 6. — ^Annual Quoddy Region sea scallop landings (meats) 

 at present ( 10-year mean) and as predicted after dam 

 construction 



Sea scallop popvilations are found 

 only in the deeper portions of the low 

 pool, so it is unlikely that anticipated 

 changes in water level and salinity will 

 adversely affect their survival. Land- 

 ings in the low pool now account for 

 over 90 percent of the total .United 

 States Quoddy Region sea scallop catch. 

 These are expected to increase slightly 

 because of the influence of warmer 

 water. An annual increase of perhaps 

 $1,700 in earnings is predicted (table 

 6). 



SUMMARY 



This study of the scallop fishery was 

 part of the investigations on fish and 

 shellfish, oceanography, and economics 

 made in the Quoddy Region, in an at- 

 tempt to evaluate the probable effects 

 of the construction there of a hydro- 

 electric tidal power project. 



The scallop fishery is the second 

 most important mollusk fishery in 

 the United States Passamaquoddy proj- 

 ect area. Average production during 

 the period 1948-57 was over 32,000 

 pounds of meats valued at more than 

 $15,000. 



The most important changes antici- 

 pated in this area that concern the 

 scallop would be the reduction in tidal 

 water exchange, with attendant reduc- 

 tion in vertical mixing, the widened 

 range of water temperatures, and the 

 lengthened time of flushing in the high 

 pool. In the low pool, water exchange 

 and temperature will both be increased. 



It is felt that conditions for sea 

 scallop survival will be improved by 

 the impoundment and that landings will 

 increase. A prediction of doubled 

 catches in the high pool is considered 

 justified by the 50 -percent reduction 

 in water exchange. The increase inlow 

 pool catches will be comparatively 

 small. 



LITERATURE CITED 



BAIRD, FREDERICK T., JR. 



1953. Observations on the early life 

 history of the giant scallop (Pecten 

 magellanicus). Maine Department 

 of Sea and Shore Fisheries, 

 Research Bulletin No. 14, 7 pp. 



1954a. Migration of the deep sea 

 scallop ("Pecien magellanicus). Maine 

 Department of Sea and Shore 



