Physicochemical and biological sampling was conducted monthly from June 2002 through June 2004 at eight sites along the Hudson River Park (Figure 1).  Sampling started soon after debris barging ended at pier 25, and continued for 25 months.  Sampling sites were chosen to include the dredged site (pier 25, Figure 2) and seven similar undredged sites (piers 26, 32, 49, 52, 66, and 95). 

Prior to biological sampling, we measured surface and bottom water properties at each site.  Salinity and water temperature were recorded using a YSI model 30/50 S-C-T meter.  Dissolved oxygen was measured with a YSI model 51 meter.  Position and water depth were recorded from a Raytheon model RC425 chart plotter and depth finder. 

Fish were captured using a 6-m wide otter trawl with 5-cm stretch mesh netting and a 0.6-cm stretch mesh cod end liner.  The trawl was dropped close to the shoreline and pulled by the 8.5-m research vessel Acipenser toward the Hudson River channel.  Trawls were performed four times at each site per month.  Captured fish were identified to species, enumerated, and measured (TL in mm) in the field. 

Benthic macroinvertebrates were sampled using a Ponar grab (0.053 m² area) deployed two times at each site per month.  Samples were fixed with 10% buffered formalin in the field.  Upon returning to the lab, samples were rinsed through sieves with mesh sizes of 0.50 mm, 2.0 mm, and 4.75 mm, stained with Rose Bengal (84% dye content), sorted, enumerated, and identified (Jeremy Dietrich, Cornell University) to the most complete taxonomic level allowed by 40X magnification.