warmer, less saline water. In the low 

 pool, herring should be able to survive 

 the altered salinities and temperatures 

 except for localized mortality if temper- 

 atures exceed 68° F. Predicted pressures 

 and rates of pressure change between 

 turbine intakes and exits are within limits 

 that herring have been shown to withstand. 

 In passing through the turbines, some 

 fish will undoubtedly come in contact with 

 the sides of the draft tubes and with the 

 turbine blades. This contact may cause 

 some abrasion with a resultant mortality, 

 ,but the effect is expected to be insignifi- 

 cant. 



Most of the herring are taken in weirs 

 built close to shore. Analysis of weir 

 catches shows no significant relation be- 

 tween average catches inside Passama- 

 quoddy and Cobscook Bays and catches 

 in outside areas for the same year. 

 Weirs inside the bays are more efficient 

 and catch about twice as many herring 

 per weir as those outside the bays. This 

 suggests that the bays act as a natural 

 fish trap and tend to hold herring in a 

 restricted area. 



The only significant change expected 

 is a time lag in the entry of herring into 

 the bays resulting from closure of the 

 filling gates for about 19 hours in every 

 25. However, the most significant point 

 established from the results of investi- 

 gations is that year-to-year variations 

 both in individual weir catches and in 

 total catches in the various statistical 

 districts of the Quoddy Region are far 

 greater now than any that can be forecast 

 as resulting from the installation of dams. 



Groundfish 



No measurable change in groundfish 

 landings is anticipated for the Quoddy 

 Region, but there will be a change in the 

 species composition of the fraction of 

 the catch taken inside the dams. Winter 

 flounders should increase in numbers 

 since anticipated conditions will more 

 closely resemble those to the south where 

 there are important winter flounder fish- 

 eries. A larger commercial and sport 

 fishery for winter flounder is visualized. 

 The proposed structures will probably 

 eliminate the haddock fishery inside the 

 bays, but no effect is expected outside. 

 Impoundment will deny fish direct access 



to the low pool and therefore sharply 

 reduce the pollock fishery there. 



Mo Husks 



It may be assumed that clam production 

 will vary with the size of the intertidal 

 zone. This zone will change in size and 

 position if dams are installed. In the 

 high pool, which yields roughly half the 

 total clam production in the Quoddy Re- 

 gion, the present beds will be permanently 

 submerged. Consequently, clam produc- 

 tion will decrease drastically with im- 

 poundment. There will be no substantial 

 clam production in the high pool until 

 new beds are established at new inter- 

 tidal levels and until the clams there have 

 grown to marketable size. This should 

 take from 6 to 10 years and even then 

 production may be only 5 percent of its 

 present volume. In the low pool, produc- 

 tion should drop to 50 percent of the 

 present small volume, but after 6 to 10 

 years it should rise to the present vol- 

 ume. In the outside area no changes are 

 anticipated. 



Impoundment is expected to increase 

 scallop landings substantially in the 

 Quoddy Region. In the high pool, flushing 

 times may be doubled and hence condi- 

 tions for retention of the pelagic larvae 

 improved. In the low pool, improved 

 conditions for feeding and survival should 

 increase production slightly. In the out- 

 side areas there are likely to be no 

 changes. 



Turbidity and water temperature are 

 important factors regulating shipworm 

 distribution. The threshold temperature 

 for spawning in Teredo navalis is 61° F. 

 Because of the expected increase in water 

 temperature in summer, a rapid spread 

 of shipworms to all parts of both pools 

 may be expected. The outside area will 

 not be affected appreciably. 



Lobsters 



It is anticipated that only the stocks of 

 lobsters inside the dams will be affected. 

 The present fishery is carried out almost 

 exclusively in Passamaquoddy Bay. If the 

 bay becomes ice covered, the present 

 winter fishery would be impossible but 

 lobsters could be harvested equally well 

 in another season. Predicted increases 

 in surface temperatures during the 



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