1.0 INTRODUCTION 



A major portion of the sediment dredged annually from our nation's harbors and 

 navigation channels has the potential for beneficial use. Habitat development, an important 

 example of such a use, has been employed in the construction, restoration and 

 enhancement of a variety of coastal habitats including salt marshes, oyster beds, and 

 waterbird nesting sites (e.g., Yozzo, Titre, and Sexton, 1996; Pamell, DuMond, and 

 McCrinraion, 1986). Since 1988, the US Army Engineer New England District (CENAE) 

 has been examining construction of intertidal flats as a viable alternative to dredged 

 material disposal (Fleming et al., 1991). Construction of intertidal flats as a beneficial use 

 of dredged materials has previously been suggested by Kirby (1995) as a mechanism to 

 replace lost habitat and protect fragile shorelines from erosion. Hosokawa (1997) has also 

 supported the concept as a method of restoring lost sandy intertidal habitat in Japan. 

 Monitoring of constructed sand flats in Japan has indicated rapid colonization of deposited 

 sediments and establishment of benthic conmiunities similar in biomass to namral flats 

 (Hosokawa, 1997; Okada, Lee, and Nishijima, 1997). 



Intertidal flats account for 15.6% of coastal wetlands along the North Atlantic coast 

 of the United States (Field et al., 1991). Providing high levels of primary productivity and 

 forage for conunercial fisheries species, they are ecologically and commercially important 

 (Peterson and Peterson, 1979; Whitlach, 1982). Intertidal flat primary producers, 

 dominated by microalgae such as diatoms, provide a third of the total organic carbon 

 budget for southern New England coastal areas (Marshall, 1970) and in the South Atlantic 

 provide up to 50% of total estuarine primary productivity (Pinckney and Zingmark, 1993). 

 Unlike vascular plants, whose high proportion of structural materials requires lengthy 

 decomposition periods, microalgae represent a concentrated and immediately accessible 

 food source to higher trophic levels (Olivier et al., 1996). The principal consumer groups 

 are dense assemblages of benthic invertebrates comprised primarily of polychaetes, 

 amphipods, and molluscs (Larsen and Doggett, 1991). These assemblages serve directly 

 and indirectly as forage for demersal fish and migratory shorebirds. Winter Flounder 

 ( Pleuronectes americanus ), a commercially important fish species, feed heavily on the 

 intertidal flat infauna (Wells, Steele, and Tyler, 1973). Juvenile flounder and other fishes 

 such as Atlantic herring ( Clupea harengus ), Atlantic Tomcod (Microgadus tomcod ), 

 Atlantic Cod (Gadus morhua ), longhom sculpin ( Myoxocephalus octodecemspinosus ) , 

 shorthorn sculpin, ( M. scorpius ), little skate (Raja erinacea), oceanpout ( Macrozoarces 

 americanus ), and sea raven ( Hemitripterus americanus ) are commonly found on intertidal 

 flats (Tyler, 1971). In addition, intertidal flats support large populations of sand shrimp 

 (Crangon septemspinosus ) which are forage for flounder, other bottom feeding fishes, and 

 migratory shorebirds (Schneider and Harrington, 1981). Many shorebirds including 

 dowitchers, sandpipers, sanderlings, and plovers use Bay of Fundy and Maine intertidal 



Ecological Monitoring of a Constructed Intertidal Flat at Jonesport, Maine 



