sediment and monitor development of soft-clam and bait- worm populations, and benthic 

 macro-invertebrate (infauna) communities. During the initial sampling trip (1990), local 

 residents informed project personnel of an earlier dredged material deposit placed during 

 the 1960's at nearby Beals Island (Figure 1-4). The Beals Island disposal operation 

 occurred prior to the National Environmental Protection Act (NEPA) and apparently no 

 records were kept of the precise location of the disposal area. An area corresponding to 

 residents' descriptions was examined and the presence of stiff clays similar to dredged 

 sediments (clay balls) below the sediment surface seemed to confirm the area as a disposal 

 site. In 1991, the Beals Island site was added to the study as an example of a much older 

 (approximately 30 years) constructed intertidal flat. 



In June 1990 the New England District (CENAE) and Normadeau Associates 

 conducted a survey of soft-clam populations, infauna and sediments at Sheep Island. All 

 sampling in subsequent years occurred in August or September during the lowest tides 

 available. In 1991, CENAE personnel and members of the Waterways Experiment 

 Station's Coastal Ecology Branch (CEB) repeated the sampling of Sheep Island, extended 

 the survey to include bait- worms, and sampled the constructed flat and an appropriate 

 reference area at Beals Island. This sampling scheme was repeated in 1992. Only the 

 Beals Island site was accessible in 1993 due to inclement weather. Infaunal and sediment 

 samples were taken but no bait-worm or soft-clam sampling occurred. Infauna and 

 sediments were sampled at both sites in 1994. In 1998 sediments, infauna, and bait-worm 

 and soft-clam populations were sampled at Sheep Island, while at Beals Island only infauna 

 and sediment samples were taken. 



2.3 Data Collection 



Bait-worm and soft-clam samples were taken using several different methods 

 (Tables 2-1 and 2-2). Sampling methods changed from year-to-year as progressively more 

 experience was gained and limitations of individual methods were recognized. In 1990 and 

 1991 thirty 0.04 m^ pits were dug using a shovel and sediments were rinsed over a 0.63 cm 

 (0.25 in.) mesh screen. Soft-clams collected on the screen were identified, counted, and 

 specimen widths measured to the nearest mm in the field. When sampling was expanded to 

 include bait- worms in 1991, it was recognized that while this method provided quantitative 

 samples it would not capture the full range of different sized worms due to the small 

 sampling area. In particular, it would undersample large commercial-size animals. Clam- 

 worms can reach 90 cm in length (Pettibone, 1963) and the maximum dimension of the pits 

 was only 20 cm. Commercial worm rakes were employed in order to collect these larger 

 specimens. Rakers collected all specimens encountered during a series of 5-minute 

 sampling periods, counted the specimens and measured their total lengths to the nearest 

 mm. Although this procedure resulted in collection of large animals it was relatively 



Ecological Monitoring of a Constructed Intertidal Flat at Jonesport, Maine 



