Data on the distribution, height, and condition of impoundments in the Maine 

 coastal zone show that of the 176 surveyed impoundments, only 20 were equipped 

 with fish passage facilities. These dams caused much of the decline of 

 anadromous fish runs in Maine. Over 20 rivers in Maine originally supported 

 Atlantic salmon runs; that number declined to less than 9 by I960 (Everhart 

 1958). A recent report by the U.S. Army Corps of Engineers (1979) on the 

 hydroelectric potential at existing dam sites in New England identifies a 

 total of 276 dams (20% of the state total) in the characterization area. 

 Nineteen of these dams are currently generating power, 56 are either partially 

 breached or need total reconstruction, and 201 are existing structures 

 currently in use for purposes other than hydropower. Of the 257 sites, 96 

 have a potential generating capacity greater than 50 kw at 40% capacity. 

 These are the sites most likely to be developed first for hydroelectric power 

 generation (see atlas map 4) . 



The problems dams present to migrating fishes are by no means eliminated by 

 the installation of fish passage facilities. Most fish passage facilities aid 

 upstream migrating fishes but provide little, if any, help to downstream 

 migrating fishes and juveniles. Undirected, the downstream migrants follow 

 the flow of water over spillways or through conduits and turbines. Mechanical 

 and thermal mortality or injury often result. Where falls or spillways are of 

 sufficient height to create fall velocities approaching 40 feet/sec or 12 

 m/sec (about 25 feet or 8 m of head) , potential for damage to fishes exists 

 (Bell 1973). Although this is not usually a major problem of low-head 

 hydroelectric dam facilities, of the 256 existing nonhydroelectric dam sites 

 in the coastal zone, at least 17 have a gross head greater than 25 feet. 

 Also, fishes tend to concentrate at fish passage facilities (waiting to go up 

 or down) . This concentration increase their availability to anglers and they 

 also may be easy prey for birds and other predators. 



Fish passage facilities do not always work well. Fishway configurations vary 

 in approach, length of run, slope, number and size of resting pools, water 

 levels and flows, and velocities. Many species require special design 

 features and it is difficult to build a fish passage facility that acommodates 

 all sizes or species of fish. The ability of a fish to negotiate a fishway or 

 ladder is highly dependent on its swimming speed and sensory behavior. 

 Sturgeon do not successfully pass pool type fishways (Bell 1973). They must 

 be moved via elevator (lock), be carried, or trucked over. There are no such 

 facilities in Maine. Striped bass and rainbow smelt are also very reluctant 

 to use many fishways (personal communication from B. Rizzo, U.S. Fish and 

 Wildlife Service, Newton Corner, MA; November, 1979). All of the existing 

 fish passage facilities in Maine are either Denil fishways or vertical slot 

 type. These facilities are suitable for passage of Atlantic salmon, American 

 shad, blueback herring, alewife, sea lamprey and most trout (personal 

 communication from B. Rizzo, Ibid ) . 



Water Quality 



Aquatic environments are the eventual sinks for most wastes and pollutants. A 

 number of water quality and water chemistry parameters have profound effects 

 on fishes, and human activities have demonstrable effects on these parameters. 

 These water quality parameters include turbidity, dissolved oxygen, pathogens, 

 toxicants, radioactivity, nutrients, and pH. The major water quality problems 

 in coastal Maine are described in chapter 3, "Human Impacts on the Ecosystem." 



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