Williams, L. W. 



1983. Larval fish assemblages of lower Mobile Bay. M.S. 

 Thesis, Univ. South Alabama, Mobile, 55 p. 



James G. Ditty 



Louisiana Department of Wildlife and Fisheries 



Seafood Division 



P.O. Box 98000. Baton Rouge, LA 70898-9000 



Present address: 



Coastal Fisheries Institute 



Center for Wetland Resources 



Louisiana State University 



Baton Rouge. LA 70803-7507 



Glen G. Zieske 



Louisiana Department of Wildlife and Fisheries 



Seafood Division 



P.O. Box 98000, Baton Rouge. LA 70898-9000 



Richard F. Shaw 



Coastal Fisheries Institute 

 Center for Wetland Resources 

 Louisiana State University 

 Baton Rouge. LA 70803-7507 



UTILIZATION OF A WASHINGTON 



ESTUARY BY JUVENILE 



ENGLISH SOLE, PAROPHRYS VETULUS 



The use of west coast estuaries and protected bays 

 as nursery grounds by English sole, Parophrys 

 vetulus Girard, a significant component of Pacific 

 coast groundfish landings, has been well docu- 

 mented (Westerheim 1955; Kendall 1966; Smith and 

 Nitsos 1969; Misitano 1970). From data collected off 

 Oregon, Laroche and Holton (1979) showed that 

 English sole also utilize nearshore areas along the 

 open coast as nursery grounds. Krygier and Pearcy 

 (1986) determined that estuarine dependence for 

 juvenile English sole was indeed significant relative 

 to the open coastal area off Oregon, although their 

 survey design made it difficult to compare absolute 

 abundance in these areas. In addition, the estuaries 

 studied by Krygier and Pearcy were much smaller 

 than the Washington estuaries of Grays Harbor and 

 Willapa Bay, making it difficult to extrapolate their 

 results. 



In the present study our objectives were to 1) 

 compare relative density and estimates of abun- 

 dance of 0-age English sole between a Washington 

 estuary. Grays Harbor, and the adjacent area along 

 the open coast; 2) compare fish density between 

 several subareas (strata) of each system; and 3) note 



timing of immigration to and emigration from the 

 estuary. Specific gear was developed to efficiently 

 sample small benthic organisms and was used in 

 both the estuary and open coast survey areas, elim- 

 inating the need for gear selectivity intercalibration. 

 In addition, the statistical design of the survey en- 

 abled population estimates with confidence intervals 

 to be made for each area. 



Methods and Materials 



Survey Design 



For this study, we specifically developed a plumb 

 staff beam trawl with an effective width of 2.3 m. 

 We designed it for a quantitative assessment of 

 juvenile fishes and crustaceans closely associated 

 with the bottom. Its fine mesh (4 mm) cod end liner 

 retained newly settled flatfish (15-25 mm total 

 length). A complete account of its construction, 

 method of deployment, and field testing was given 

 by Gunderson and Elhs (1986). 



We selected two separate survey areas for the 

 study, the Grays Harbor estuary and the adjacent 

 nearshore area along the open coast. The estuarine 

 survey was based on a stratified random statistical 

 design and the open coast survey on a systematic 

 trackline. Both areas were surveyed in 1983 and 

 1984. 



The estuary was stratified into four geographic 

 areas (Fig. 1). Each stratum was divided into 1 x 

 1 km grids (1 km intervals in the case of narrow 

 channels), and several stations were then random- 

 ly selected with the constraint that no two be adja- 

 cent. Additional stations were added in both STR 

 (stratum) 1 and 2 for the 1984 survey. 



For the open coastal survey, three tracklines 

 oriented perpendicular to the bathymetry were 

 located off Copalis Head, Westport, and Willapa Bay 

 (Cape Shoalwater) (Fig. 2). We established a sys- 

 tematic series of stations along each trackline at 9 

 m depth intervals from 9 to 64 m. Whenever wave 

 conditions permitted, we sampled an additional sta- 

 tion at 5.5 m. In 1984, the 64 m stations were 

 dropped on each trackline because of consistent gear 

 damage in 1983. Also in 1984, replicate tows were 

 made at the 27 and 37 m stations. 



Sampling Schedule 



We sampled the estuary twice monthly from April 

 through September 1983 and 1984, and a single trip 

 was made in January 1984 for continuity. The two 



fishery BULLETIN: VOL. 86, NO. 4, 1988. 



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