161 
Abstract . — Growth and mortality 
rates of 0 + English sole were estimated 
from field data collected from estuarine 
and nearshore nursery areas off Wash- 
ington during 1985-88. Growth of 0 + 
English sole was approximately linear 
over time and was estimated with the 
length modal progression method. 
Point estimates of growth rates during 
May through September were in the 
range of 0.33 to 0.49 mm/day. Statisti- 
cal analysis with a general linear model 
showed significant year and settlement 
time effects on growth of 0 + English sole 
but failed to detect any density or tem- 
perature effect. Instantaneous mortal- 
ity rate varied significantly with sea- 
son, declining from 0.0175 per day in 
July and August to 0.0075 per day in 
September. Changes in population den- 
sity appeared to play a minor role in 
causing this decline. 
Manuscript accepted 30 July 1996. 
Fishery Bulletin 95:161-173 (1997). 
Growth and survival of 0+ English sole, 
Pleuronectes vetulus, in estuaries and 
adjacent nearshore waters off 
Washington 
Yunbing Shi* 
Donald R. Gunderson 
School of Fisheries, 357980, University of Washington 
Seattle, Washington 98195 
E-mail address: yshi@HARZA.com 
Patrick J. Sullivan 
International Pacific Halibut Commission 
RO Box 95009, Seattle, Washington 98145 
Fish growth depends on numerous 
factors, e.g. supply of suitable prey 
items, ambient temperatures, and 
oxygen concentration. Laboratory 
studies have shown that growth of 
juvenile plaice ( Pleuronectes pla- 
tessa), sole (Solea solea), and En- 
glish sole ( Pleuronectes vetulus) de- 
pends strongly on ambient tempera- 
ture (Williams and Caldwell, 1978; 
Fonds, 1979; Yoklavich, 1981). 
Field observations also show that 
growth of flatfishes is regulated by 
ambient temperature. Applying a 
model based on Fonds’s ( 1979) labo- 
ratory experiment and observed 
temperature data for predicting 
monthly growth of North Sea pla- 
ice, van der Veer et al. (1990) 
showed a close overall agreement 
between predicted growth incre- 
ments and those observed in the 
field. Simulated growth rates, how- 
ever, were consistently lower than 
field-observed growth rates in June, 
and this tendency was reversed in 
August (Fig. 7 in van der Veer et 
al., 1990). This finding suggests 
that in addition to temperature 
there are other factors that also af- 
fect the growth of plaice. 
Laboratory studies of juvenile 
English sole (Williams and Cald- 
well, 1978; Yoklavich, 1981) have 
shown that food limitation can sig- 
nificantly reduce growth. Edwards 
and Steele (1968) suggested that 
food limitation was the controlling 
factor for the growth of North Sea 
plaice in Loch Ewe. Bergman et al. 
( 1988) reported that growth reduction 
of 0-group plaice occurred in specific 
areas of the Wadden Sea where there 
was low food abundance, although 
this phenomenon was restricted to 
only a small part of the population. 
Isolating the effects of fish den- 
sity, food supply, and ambient tem- 
perature on growth is difficult with 
field data. Within a certain range 
of population density or food abun- 
dance, growth may be regulated 
primarily by temperature and, 
within a certain range of tempera- 
ture, population density may have 
a dominant influence. 
Survival is the key element in 
determining success of recruitment. 
Early research was largely focused 
on the “critical period” theory 
(Hjort, 1913), i.e. survival of small 
first-feeding larvae is critical to sub- 
sequent year-class strength. More 
recent studies have shown that low 
* Present address: HARZA Consulting En- 
gineers and Scientists, 2353 130th Avenue 
N.E., Suite 200, Bellevue, WA 98005. 
