GROWTH OF JUVENILE ENGLISH SOLE, PAROPHRYS VETULUS, IN 

 ESTUARINE AND OPEN COASTAL NURSERY GROUNDS 



Andrew A. Rosenberg 1 



ABSTRACT 



The growth of English sole juveniles, during 1978-79, from estuarine and open coastal nursery 

 grounds on the Oregon coast is described in detail. Counts of fortnightly growth rings on otoliths 

 were used to determine size-at-age. Mean growth rates were similar for the two areas, but variabil- 

 ity in size-at-age was much greater among fish captured in the estuary. 



Back calculation of individual growth, using radial measurements on the otoliths, showed that 

 growth proceeds linearly during the first year of life. Differences in average growth among indi- 

 vidual fish account for the high variability in size-at-age among fish found in the estuary. Fish from 

 the estuary grew slightly faster, on average, in 1979 compared with 1978. 



The settlement date of English sole larvae to the benthic habitat, determined from age data, 

 occurred over the winter and spring in the open coastal nursery area. In the estuary, settlement 

 was concentrated in the early winter. 



The life cycle of many marine fishes contains a 

 stage in which the juveniles of the species are 

 concentrated in a specific area or nursery 

 ground where the adults are uncommon. On both 

 the east and west coasts of North America, es- 

 tuarine areas are extensively used as nursery 

 grounds for a large number of species (Gunter 

 1961; Pearcy 1962; McHugh 1967; Haedrich in 

 press). Many east coast fishes are considered to 

 be dependent on estuarines during early life. On 

 the west coast, estuarine dependence has not 

 been clearly demonstrated (McHugh 1967; 

 Pearcy and Myers 1974). 



The high productivity of estuarine areas, pro- 

 viding improved growth conditions for juvenile 

 fish, the apparent lack of large predators, and re- 

 duction of competition among age groups of a 

 species are frequently invoked explanations for 

 estuarine dependence (Haedrich in press; 

 Kuipers 1977). Unfortunately, it is difficult to 

 test these hypotheses for most species of fish, be- 

 cause it is uncommon to find a species which uses 

 both estuarine and nonestuarine nursery envi- 

 ronments in a small geographic area. 



The commercially important pleuronectid 

 Parophrys vetulus Girard, found off the Oregon 

 coast, uses both estuarine and nonestuarine habi- 

 tats as nursery areas during the first year of life 

 (Laroche and Holton 1979). This study examines 

 the growth of the English sole, Parophrys vetulus, 



•School of Oceanography, Oregon State University, Cor- 

 vallis, Oreg.; present address: Department of Biology, Dal- 

 housie University, Halifax, Nova Scotia, B3H 4J1 Canada. 



juveniles from two nursery grounds: the Ya- 

 quina Bay estuary (Pearcy and Myers 1974) and 

 the open coastal area off Moolach Beach, Oreg. 

 (Laroche and Holton 1979). 



Size-at-age data, obtained from daily and fort- 

 nightly growth ring counts on otoliths, are used 

 to detail growth during the first year. Daily 

 growth rings on otoliths have been documented 

 in many species of fish (Pannella 1971; Brothers 

 et al. 1976; Struhsaker and Uchiyama 1976; Tau- 

 bert and Coble 1977). Pannella (1974) reported 

 fortnightly banding patterns in several species 

 as well. Laroche et al. (1982) have provided lab- 

 oratory evidence for the daily periodicity of 

 growth rings on P. vetulus otoliths. 



METHODS 



Sampling was conducted from September 1978 

 through September 1979 at Moolach Beach and 

 Yaquina Bay. The sampling stations are shown 

 in Figure 1. A tow was made at each station with 

 a 1.5 m wide beam trawl lined with 7 mm stretch 

 mesh. Tows were for 5 min in Yaquina Bay and 

 for 10 min at Moolach Beach. The beam trawl 

 was equipped with a 1.0 m circumference odom- 

 eter wheel to measure distance travelled on the 

 bottom. Measurements of bottom temperature 

 and salinity were made at each station. 



All fish captured were preserved in a strongly 

 buffered 10% solution of Formalin 2 in seawater. 



Manuscript accepted November 1981. 

 FISHERY BULLETIN: VOL. 80, NO. 2, 1982. 



2 Reference to trade names does not imply endorsement by 

 the National Marine Fisheries Service, NOAA. 



245 



