Eh. Hernandez et Lr. Castro, Larval growth of the anchoveta Engraulis ringens during the winter spawning season off central Chile, FISH B, 98(4), 2000, pp. 704-710
Larval growth rates of the anchoveta Engraulis ringens were determined for
two periods during the winter spawning season off Talcahuano, central Chile
. Because winter is the season of minimum plankton production during the ye
ar, we hypothesized that larval growth rates during winter should be consta
ntly low because of decreased larval fish food availability. Our results, h
owever, indicate that 1) mean larval growth rates determined from three gro
wth models in winter (mid-July through mid-September) were as high as in ot
her periods of the year (linear, Gompertz, and von Bertalanffy; 0.47 mm/d,
0.50 mm/d, and 0.48 mm/d, repectively); 2) differences in larval growth rat
es occurred in two groups of cohorts spawned in the two periods during the
spawning season (0.40 mm/d vs. 0.57 mm/d); and, 3) larval food (dinoflagell
ates, copepod eggs, and copepod nauplii) concentrations in the field were r
elatively high and not very variable during the study. Hydrography of the w
ater column, however varied throughout the season. During the last weeks of
the study seawater temperature was higher, indicating intrusion of offshor
e warmer waters into the coastal zone. The presence of these warmer waters
suggests that differences in growth rates between groups of cohorts may hav
e resulted from larval development in water with different characteristics.
Consequently, for a coastal upwelling species such as the anchoveta, incre
ased growth rates in some cohorts may be advantageous considering that its
main spawning season occurs in winter when the environmental conditions flu
ctuate markedly in short, time scales.