FISHERY BULLETIN: VOL. 85, NO. 4 



the two salinity regimes and microhabitats con- 

 stituting the creek and shoal sites. 



STUDY AREA AND METHODS 



The York River estuary, a subestuary of the 

 Virginia portion of the Chesapeake Bay (Fig. 1), 

 covers about 208 km^ and extends 46 km from 

 Tue Marsh Light to West Point, where it is 

 formed by the confluence of the Pamunkey and 

 Mattaponi Rivers. At two localities within the 

 estuary, tidal creeks similar in physical dimen- 

 sions (O'Neil 1983), but differing in salinity 

 regimes, were selected as study sites: Goalders 

 Creek, a meso-oligohaline site (sensu Remane 

 1934 and the Venice System of classification), and 

 Blevins Creek, a polyhaline creek in the Guinea 

 Marshes near the mouth of the river (Fig. 1). 



Field Methods 



Within each locality three stations were estab- 

 lished: 1) in each creek approximately 1,500- 

 2,000 m upstream (where trawling was still possi- 

 ble), 2) immediately inside the creek mouth, and 

 3) at shoal stations positioned approximately 200 



m offshore in the York River proper in approxi- 

 mately 3 m of water. 



Monthly collections (March-October 1982) with 

 a 4.9 m semiballoon otter trawl with wings and 

 body of 19 mm mesh and a 6.3 mm mesh cod end 

 liner were made during daylight hours as close to 

 high tide as possible. Four 2-min tows at about 

 1 m s"^ were made at each station. 



To reduce the chances of regurgitation, speci- 

 mens were initially anesthetized in a mixture of 

 seawater and 0.02 mL quinaldine (mixed in 10 

 mL acetone). Buffered formalin (10%) was then 

 added for preservation. The abdominal cavities of 

 large fish (>80 mm) were pierced to allow suffi- 

 cient preservation of food items in the stomach. 

 Water temperature and salinity were recorded 

 prior to trawling at each station. 



Laboratory Methods 



In the laboratory, spot from each collection 

 were sorted and counted. Individual standard 

 lengths (SL) were measured; when more than 50 

 spot were captured in a single collection, a ran- 

 dom subsample of 30 fish was used for length 

 measurements. 



XJb.:$2^ vsv^ 



YORKTOWN 



Figure 1. — York River, VA, and relative locations of tidal creeks examined. A 



Creek. 



Goalders Creek, B = Blevins 



786 



