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COMPARISON OF GROWTH AND REPRODUCTION BETWEEN TWO POPULATIONS OF SARGASSUM SILIQUASTRUM IN PING CHAU, HONG KONG
Author(s) -
Chan W.Y.,
Ang P.O.
Publication year - 2000
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1046/j.1529-8817.1999.00001-34.x
Subject(s) - biology , reproductive season , population , reproduction , phenology , waves and shallow water , zoology , ecology , demography , oceanography , sociology , geology
In Ping Chau Island of Hong Kong, two populations of Sargassum siliquastrum are present. One is in the shallow water of about 1 to 3 m Chart Datum (CD), and the other one in deeper water of 5 to 10 m CD. These two populations are separated by an extensive sand patch. Individuals of the “shallow” water population increased their size from a mean length of 8.3 ± 3.6 (SD) cm in Aug 1998 to a maximum of 48.2 ± 29.9 cm in early Jan 1999 before they started to die back. In the following year, they attained a minimum of 6.1 ± 3.8 cm in May 1999 and a maximum of 56.1 ± 23.6 cm in Dec 1999. Their reproductive period lasted for two to three months from Jan to Feb 1999, and again from Nov 1999 to Jan 2000. The “deep” water individuals increased their size to a maximum of 123 ± 50.8 cm at the end of Jan 1999 and started to die back in Feb, 1999. They again reached their maximum mean length in Jan 2000. Their reproductive period lasted for five to six months from Sept 1998 to Feb 1999 and again from Sept 1999 to Jan 2000. The “deep” water individuals tended to be longer in size and they attained their maximum growth a month later than the “shallow” water individuals. Their reproductive season tended to start earlier and lasted longer than those in the “shallow” water. These differences in the phenology of the two populations may be related to the temperature differences (up to 5° C difference in summer) between the two depths. Sargassum siliquastrum is likely to be a cold adapted species such that warmer temperature in the shallow water has compressed and shortened their rapid growth and reproductive period to within the few colder months in fall and winter.