260 



CiHisial & Miinuc Ecdsysltmi — Our Living Resources 



human population trends and the status of Keys" 

 reefs combined with information collected from 

 commercial fisheries' landings lo infer the 

 health of reef fishes: no single reef site has ever 

 been repeatedly surveyed for fish abundance 



over time. This example clearly demonstrates 

 that to better judge the status of our coastal and 

 marine resources in the future, carefully chosen 

 and designed long-term monitoring is required. 



Nearshore 

 Fish 



Assemblage of 

 the Tidal 

 Hudson River 



by 



Robert A. Daniels 



New York Stale Museum 



Biological Surrey Laboratory 



Painting of pumpl^inseed 

 (Lepomis gibbosus). a persistent 

 species of the Hudson River. 



Courtesy NY Environmental Conservalion Depanment 



The Hudson River drains about 43,000 km" 

 (17,370 mi-), most of it in eastern New 

 York. Although this is a young river with a rel- 

 atively small watershed at higher latitudes, the 

 Hudson and its tributaries support a rich fish 

 fauna of more than 200 species (Smith and Lake 

 1990). This fauna is a diverse mixture of native 

 and exotic freshwater species, diadromous 

 (migratory between fresh and salt waters) fish, 

 and marine strays (Barnhouse et al. 1988). More 

 than 150 of these species are reported from the 

 tidal portion of the river that extends 243 km 

 (151 mi) from the Battery on Manhattan Island 

 to the Troy Lock (Fig. I); of these, about 80 

 species are freshwater or diadromotis forms and 

 50 species occur regularly in nearshore areas 

 (Smith 1985). During the last half-century, the 

 nearshore fauna of the tidal portion of the river 

 has undergone two types of changes: species 

 have been added to and deleted from the fauna 

 and the relative abundances of the dominant 

 species have changed. 



I explore differences in the nearshore fish 

 assemblages of the Hudson River by comparing 

 infonnation on the distribution and abundance 

 of fish collected between 1936 and 1990. This 

 comparison offers only a coarse look at change 

 in the fish assemblage and provides little infor- 

 mation on trends. The nearshore fish assem- 

 blage of the Hudson River is dynamic and 

 changes on a daily, seasonal, and annual basis. 



Surveys of Fish Fauna, 1936-92 



The study of Hudson River fish dates to 

 Samuel Mitchilfs publication on the fish of 

 New York (Mitchill 1815). DeKay (1842) and 

 Bean ( 1903) also provided information on fish 

 in the Hudson River, but the first synoptic sur- 

 vey of the fish in the river system was not 

 undertaken unfil 1936 (Greeley 1937). The 

 watershed surveys of New York conducted 

 between 1926 and 1939 included a detailed sur- 

 vey of fish distribution and abundance in the 

 lower Hudson River drainage. Fish collected 

 during these surveys were vouchered; speci- 

 mens are housed at the New York State Museum 

 (NYSM). Beginning in the eariy 1970"s, interest 

 in the fish of the Hudson River increased dra- 

 matically (Limburg et al. 1986), and several 

 long- and short-term monitoring programs 

 began. Data collection continues in many of the 

 long-term programs. 



flutist )n Ri\cr 



To examine change in the nearshore fish 

 assemblage of the Hudson River, I used select- 

 ed information from the 1936 watershed survey; 

 NYSM surveys conducted between 1990 and 

 1992; intensive site surveys conducted between 

 1976 and 1979 by Lawler. Matusky and Skelly 

 Engineers (LMS); and surveys supported by 

 Con Edison between 1974 and 1989. Because 

 techniques and equipment vary among the sur- 

 veys, I have included in the analyses only infor- 

 mation collected by workers using seines. Still, 

 the size of the seines used, the mesh size, and 

 the area sampled differ among the surveys and 

 contribute a bias not easily quantified. Because 

 this analysis is relatively coarse, any biases that 

 may exist in the data should be masked. 

 Furthermore, in most of the analyses I have 

 made comparisons within data bases. 

 Comparisons between data bases are used pri- 

 marily with presence and absence applications. 



The 1936 watershed survey collected infor- 

 mation on fish from 112 sites in the tidal 

 Hudson River (Fig. 1 ). All sampling was con- 

 ducted during summer. Fish collected during 

 this survey were identified and counted or 

 ranked; the ranking system may have varied 

 among the crews. To compare abundance. I 

 assigned numbers to the ranks in the fieldbooks 

 and compared my assigned number to the actu- 

 al number of preserved fish. In 20 comparisons 

 of each of the five ranks, the assigned number 

 equaled or undenepresented the number pre- 

 served 73% of the time; therefore, the abun- 

 dance estimates should be conservative. 



Between 1990 and 1992, I collected infor- 

 mation on fish abundance and distribution from 

 several sites on the tidal portion of the Hudson 

 River. Most information discussed here is from 

 work done at four sites during the summer of 

 1990 (Fig. 1 ). These sites typified the nearshore 



