Our Liviiii; Rfsoiircfs — Ciuistul & Marine Ecosystems 



261 



habitats present along the entire main channel. 

 LMS intensively collected fish from four sites 

 between 1976 and 1979 (Fig. 1). Day and night 

 sampling, using seines to collect fishes at week- 

 ly or biweekly intervals, began early in spring 



Table 1. Fresliuater and diadronioiis fishes collected from 

 nearshore areas of the Hudson River. 1936-92. Records 

 from 1 9.'!fi are from the watershed survey of the lower 

 Hudson River, with identifications verified, and specimens 

 vouchered. Records from 1974-89 are from the Con 

 Edison data base, no specimens vouchered. Records from 

 1990-92 are from New York State Museum (NYSM) sur- 

 veys and other additional specimens, vouchered. 



and continued until December. The data base 

 from Con Edison includes information from 

 31.582 nearshore. shallow-water sites through- 

 out the 243-km (151 -mi) course of the lower 

 Hudson River. These collections were made 

 between 1974 and 1989, 



Changes, 1936-90 



The changes in the nearshore fish assem- 

 blages of the Hudson River that have occurred 

 during the past six decades are illustrated in 

 several ways. First, the component species have 

 changed, although species richness (number of 

 species in the assemblage) has remained rela- 

 tively constant (Table 1). During the 1936 sur- 

 vey, the assemblage had 43 freshwater and 

 diadromous species. Based on recent NYSM 

 collections, the assemblage consists of 38 

 species. Recently introduced to the river are 

 gamefishes such as northern pike {Esox Indus) 

 and white crappie [Poiiio.xis annularis) and 

 exotic fishes such as rudd (Scanlinius ery- 

 thwphthalmus) and grass carp 



(Ctenopharyngodon idella). Two additions 

 from undocumented sources also included the 

 gizzard shad {Dorosoma cepedianum) and 

 freshwater drum (Aplodiuotus grunniens). 

 Several species that remain common in tributary 

 streams are now extirpated or extremely rare 

 (e.g., bridle shiner). 



In addition, the relative abundance of most 

 resident species (excluding diadromous forms) 

 has changed (Table 2). The two dominant resi- 

 dent species in 1936 (spottail shiner [Notropis 

 hudsonius] and white perch \Moroiie anieh- 

 cana]) made up 34% of the individuals in the 

 assemblage. The same two species remained 

 dominant in the 1990 survey, but have almost 

 doubled their relative abundance to 64% of the 

 individuals in the assemblage. The relative 

 abundances of an additional five persistent 

 species have declined between the two sam- 

 pling events, but only slightly. Thus, declines in 

 relative abundance were most noticeable in the 

 remaining species (not dominant or persistent) 

 of the freshwater component of the river fish 

 assemblage. In 1936, 36 species made up 26% 

 of the catch, while the remaining species 

 accounted for 7% in 1990. 



The diadroinous fishes typically dominated, 

 by number, the nearshore assemblage during 

 summer (Fig. 2) because of the presence of 

 young-of-year individuals. The most common 

 species in all samples included blueback her- 

 ring (Alosa aestivalis), alewife (A. pseudo- 

 liarengus), American shad (A. sapidissinia). bay 

 anchovy (Anchoa mitchilli). American eel 

 (Anguilla rostrata), and striped bass (Morone 

 saxatilis). The difference between 1936 and all 

 other years was the curious near-absence of 



PA 



Coxsackiei 



Catskill 



k Germantown 



Roseton i 



Lovett , 



Bowline 



New York 



The Battery 



Study areas on the 

 Hudson River 



▲ 1990 New York State Museum 

 • 1976-79 Lawler, Musky and 

 Skelly Engineers 

 1936 watershed 



Fig. 1. The tidal portion of the 

 Hudson River. New York, showing 

 areas where some fish collections 

 have been made over the last six 

 decades. 



