FISHERY BULLETIN: VOL. 84, NO. 1 



and the 1978 year class indicate that the abundance 

 of newly recruited, settling fish (<24 mm) of the 1977 

 and 1978 year classes was higher at Moolack Beach 

 than in Yaquina Bay (Fig. 5B, C). These high catches 

 at Moolack Beach were followed by a steep decline 

 in catches to the 41-44 mm size class. English sole 

 larger than 30 mm were consistently less abundant 

 at Moolack Beach than in Yaquina Bay. Densities in- 

 creased in Yaquina Bay concurrent with the steep 

 decline of 20-44 mm individuals at Moolack Beach. 

 These trends suggest immigration of young fish from 

 the shallow waters of the open coast to Yaquina Bay 

 over a range of sizes, from 20 to 40 mm. 



Two peaks occurred in the beach seine catches of 

 the 1978 year class: at 20-25 and 40-45 mm. The first 

 peak coincides with the sizes that decreased marked- 

 ly in abundance at Moolack Beach. The second peak 

 coincides with low abundance of 40-45 mm fish at 

 Moolack, and with a decrease in catches of these 

 sizes of fish at the trawl stations in Yaquina Bay. 

 These trends of trawl-caught fish suggest that im- 

 migration from Moolack Beach first occurred to the 

 shallow waters of the bay and then to the deeper 

 trawl stations. The peak in the catches of 40-45 mm 

 fish at seine stations may be caused by immigration 

 into these shallower waters of metamorphosed in- 

 dividuals from either the offshore areas or deep 

 areas of Yaquina Bay. 



Abundances and Sizes in 

 Five Estuaries 



Age-0 English sole were present in all five estu- 

 aries sampled with trawls during May and June 

 1978. The mean abundance of young English sole, 

 which ranged from 0.7/m 2 in Tillamook Bay to 

 0.02/m 2 in the Umpqua estuary, generally de- 

 creased from the northern to the southern estuaries 

 (Table 2). The exception was Yaquina Bay. It was 

 latitudinally the middle estuary, yet abundance of 

 English sole there ranked above that in Siletz Bay. 

 No consistent relationship was observed between 

 mean abundances and the area of estuaries, river 

 flows, tidal prisms, or flushing times using the data 

 of Choi (1975) or Starr (1979) 7 . 



A broad size range of fish was caught in Tillamook, 

 Siletz, and Alsea Bays, while we caught few in- 

 dividuals larger than 36 mm in the Umpqua River 

 estuary (Table 3). In Yaquina Bay, a higher propor- 

 tion of large individuals (>65 mm) was found than 

 in the other estuaries. A much broader range of sizes 



Table 2.— Mean abundance and standard deviation of 0-age 

 English sole in five estuaries north and south of Yaquina Bay and 

 along the open coast between 9 and 37 m, April-June 1978. 



was captured in these estuaries than in open coastal 

 areas on the dates sampled. 



Growth 



Despite prolonged recruitment of young English 

 sole in Yaquina Bay (Fig. 4) distinct length modes 

 were usually present for each sampling date Growth 

 rates in Yaquina Bay, estimated by following the pro- 

 gression of length modes of cohorts over time, were 

 generally greatest (0.46-0.49 mm/d) during the late 

 spring to early fall, while growth rates in winter were 

 lower (0.26-0.32 mm/d) (Table 4). The growth rate 

 from January to July 1970 was 0.47 mm/d, similar 

 to the spring-fall estimates. Growth rates were 

 estimated only for the spring-fall period off Moolack 

 Beach. These were similar to those for Yaquina Bay 

 fish but more variable, ranging from 0.28 to 0.42 

 mm/d. 



DISCUSSION 



Larvae of English sole are abundant in coastal 

 waters off Oregon, ranking first among the flatfishes 

 in some years (Richardson 1977 8 ; Richardson and 

 Pearcy 1977; Mundy 1984). Young larvae (<10 mm) 

 of English sole are rare in estuaries of the Oregon- 

 California coast as evidenced by plankton samples 



7 Starr, R. M. 1979. Natural resources of Siletz esturary. Oreg. 

 Dep. Fish Wildl., Estuary Inventory Rep. 2(4):l-44. 



8 Richardson, S. L. 1977. Larval fishes in Ocean waters off Ya- 

 quina Bay, Oregon: Abundance, distribution and seasonality, 

 January 1971 to August 1972. Oreg. State Univ. Sea Grant Publ. 

 ORESU-T-77-003. 



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