FISHERY BULLETIN: VOL. 82. NO. 3 



of the York River estuary and have included a 

 comparison of the tidal creeks with adjacent shoal 

 areas (about 200 m outside of the tidal creek 

 mouths). Along with data on community composi- 

 tion and structure, we have begun baseline studies 

 of diet composition of dominant species. These as- 

 pects of community ecology of York River tidal 

 marshes are reported herein. 



STUDY AREA AND METHODS 



The York River is one of six major tributaries 

 which enter the Chesapeake Bay along its western 

 shoreline. The narrow estuary covers about 208 

 km 2 and extends 46 km from Tue Marsh Light to 

 West Point, Va. (Fig. 1). The upper portion of the 

 York is characterized by broad, shallow flats and 

 tidal creeks dominated by Spartina spp. along the 

 shoreline. Upstream the river channel averages 

 8-9 m in depth, but broadens downstream and 

 reaches a maximum depth of 18-23 m. The Guinea 

 Marshes (Fig. 1) is a major Spartina alterniflora- 

 dominated marsh system located near the estuary 

 mouth. Much of the adjacent shallows in this re- 

 gion is carpeted with dense stands of eelgrass, 

 Zostera marina, and widgeon grass, Ruppia 

 maritima. Salinities are usually in the polyhaline 

 range. 



Two tidal creeks were selected for study. Goal- 

 ders Creek (Fig. Llocation A) was located in the 

 oligohaline-mesohaline zone just below the city of 

 West Point. Blevins Creek (Fig. l:location B), a 

 part of the Guinea Marsh system, was situated in 



the polyhaline zone where salinities always ex- 

 ceeded 16%o. In each creek, one station was estab- 

 lished as far upstream as possible, one near the 

 creek mouth, and one about 200 m offshore. All 

 collections were made monthly on consecutive 

 days (March-October 1983), with sampling ini- 

 tiated as close to daytime high tides as possible. 

 Miller and Dunn (1980) collected a greater propor- 

 tion of fish with stomachs containing food at this 

 time. Creek bottoms were of the mud-silt type and 

 ranged from 1 to 1.5 m deep. 



The primary collecting device utilized in this 

 study was a 4.9 m otter trawl consisting of wings 

 and body of 19 mm mesh and a liner of 6.3 mm 

 mesh. This gear was towed for 2-min intervals at a 

 speed of about 1.0 m/s at each station. In an earlier 

 study at Guinea Marshes, Orth and Heck (1980) 

 demonstrated that six hauls of the trawl were 

 necessary in seagrass habitats to attain asymp- 

 totic returns on community information ( as judged 

 by several diversity indices). Because of the ex- 

 pectedly lower diversity in the tidal creeks (Wein- 

 stein and Brooks 1983), it was determined that 

 four consecutive hauls at each tidal creek station 

 would be sufficient to attain the same level of 

 community information. 



Ancillary collections were taken in the tidal 

 creek with a modified Wegener ring (Wegener et 

 al. 1973). The gear was used in depths <1 m, in the 

 vicinity of the trawling stations. The side walls of 

 the ring consisted of 1.5 mm woven netting, with 

 the original design of the gear being changed to 

 include a 305 mm "skirt" and chain attached to the 



FIGURE 1. — Location of study areas in 

 York River estuary, Va. Three perma- 

 nent sampling stations were estab- 

 lished — near the headwaters, at the 

 mouth, and 200 m offshore of an oligo- 

 mesohaline (A = Goalders Creek) and 

 polyhaline (B = Blevins Creek) tidal 

 creeks. 



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