Cw. Chang et al., Recruitment and hatching dates of grey mullet (Mugil cephalus L.) juveniles in the Tanshui estuary of northwest Taiwan, ZOOL STUD, 39(2), 2000, pp. 99-106
Ages, growth, and hatching dates of grey mullet Mugil cephalus L. juveniles
in the Tanshui estuary of northwestern Taiwan were examined, using growth
increments in otoliths of fish collected in November 1995 to March 1996 and
November 1996 to March 1997. Growth increments are deposited daily, and we
re used to determine the ages. Juveniles were composed of multiple cohorts,
and their sizes ranged between 17 and 39 mm in total length, corresponding
to ages of 29 to 67 d after hatching. The growth rate during the estuarine
residency was 0.45 mm d(-1). Hatching dates back-calculated from daily age
s were from October to February, which range earlier and later than the spa
wning period from November to January of a previously known migratory popul
ation. This suggests that grey mullet juveniles in the estuary may come fro
m both a resident population and a migratory population, or that there are
earlier and later migratory spawning populations.