and high temperatures are factors that damage or destroy the reefs. In Maine, 

 action by storm waves and floating ice are more severe than in Long Island 

 Sound, so the life of some Maine intertidal mussel reefs is likely to be 

 shorter. 



The formation of the reefs begins with dense sets of mussels on stones, 

 shells, or other debris. When the first mussels become established other 

 mussels set upon them. The reef is not dependent on the underlying sediment. 

 In fact, the reefs may modify the chemical and physical characteristics of the 

 underlying sediments (Newcombe 1935) . The soft-shelled clam is smothered by 

 overlying mussel reefs (Newcombe 1935). Other infaunal species may be 

 affected similarly. 



Species living in association with mussels include worms: nematodes, 

 nemerteans, and oligochaetes . The rock barnacle and the common periwinkle use 

 the mussels as a substrate on which to attach (barnacles) or graze 

 (periwinkles). Lee (1975) found a number of polychaetes, such as Eteone 

 longa , Harmothoe imbricata, Polydora ligni, and Spio setosa , in association 

 with mussel reefs in Long Island Sound. Also present were species of the 

 crustacean genera Jaera , Corophium, Gamma r us , Melita , and Pagurus. Potential 

 predators included the green crab and the starfish Asterias sp . Although 

 communities associated with mussel reefs have not been studied in Maine many 

 of the species reported by Lee (1975) occur in Maine. 



Feeding types on mussel bars, in addition to the suspension feeding mussels, 

 include herbivores, carnivores, and deposit feeders (Lee 1975). Nematodes, 

 oligochaetes, and other deposit feeders, such as the polychaetes Nereis 

 succinea , Polydora ligni, Spio setosa, and the amphipod Corophium , thrive on 

 the pseudofeces produced by mussels. Carnivores include nemerteans, some 

 polychaetes ( Harmothoe ) and crabs. Species such as Jaera sp. and the common 

 periwinkle graze the surfaces of the substrate. Scavengers on mussel reefs 

 include the crustaceans Pagurus , Gammarus, and green crab. 



Emergent wetland . Intertidal emergent wetlands (e.g., salt marshes) are 

 productive elements of coastal areas worldwide. Because of their productivity 

 they are widely studied and data on many areas including southern New England 

 and some regions of coastal Maine are available. 



The east coast of the United States south of Cape Elizabeth, Maine, is an 

 almost entirely sedimentary environment of the type that encourages emergent 

 wetland development. In the characterization area, however, conditions are 

 such that expansive intertidal emergent wetlands are not numerous. However, 

 significant areas of intertidal emergent wetlands are narrow and fringe on 

 protected flats. These were not delineated as areal features by NWI due to 

 their linear nature. This class constitutes <3% of the total (fresh-water and 

 saline) wetland habitat and approximately 117o of the estuarine system in 

 coastal Maine (table 5-2). The southwestern regions of the characterization 

 area (1, 2, and 3) have more (in total acres and percent of total area) 

 estuarine emergent wetland than the eastern regions (4, 5, and 6). Of all the 

 estuarine classes identified by NWI, this is among the least abundant. The 

 extensive information regarding this wetland type, however, allows for a 

 disproportionately thorough discussion of this type of habitat relative to the 

 others . 



5-107 



10-80 



