SEAFDEC/AQD-Japan International Research Center for Agricultural Sciences (JIRCAS)

Mangrove zooplankton of Matang mangrove estuaries: Preliminary assessment of spatio-temporal abundance in relation to environmental parameters

Wed, 01 Jan 2003 00:00:00 GMT

Mangrove zooplankton of Matang mangrove estuaries: Preliminary assessment of spatio-temporal abundance in relation to environmental parameters Chong, Ving Ching; Ooi, Ai Lin; Chew, Li Lee; Ogawa, Yasuki Ogawa, Yasuki; Ogata, Hiroshi Y.; Maeno, Yukio; Shimoda, Toru; Fujioka, Yoshimi; Fukuda, Yutaka An on-going zooplankton study in the Matang mangrove swamp beginning April 2002 has shown that zooplankton wet biomasses determined over 5 months were relatively higher inside the mangrove swamp (1.17± 0.35 g m^-3) than in adjacent offshore waters (0.87 ± 0.55 g m^-3). Total zooplankton densities ranged from 1.2 x 10⁴ - 5.82 x 10⁴ individuals per m³ inside the swamp, whereas in offshore waters zooplankton densities ranged from 1.03 x 10⁴ - 2.83 x 10⁴ individuals per m³. Crustaceans, dominated by copepods and cirripede larvae, constituted more than 70%, followed by polychaetes and chaetognaths. Fish larvae made up less than 0.5% of the total densities. Preliminary PCA of 50 zooplankton taxa suggests that the swamp taxa but not (so much) the offshore taxa differed spatio-temporally, and that more fish larvae and young copepods were caught inside the swamp. The larval fish density (surface hauls) ranged from 12-669 individuals per 100 m^-3 inside the swamp, whereas in offshore waters it ranged from 21-290 individuals per 100 m^-3. The major families of fish larvae were Engraulididae (ca. 60%) and Gobiidae (ca. 30%). Engraulid larvae were ubiquitous in distribution occurring from swamp to 14 km offshore, while gobiid larvae were more restricted to the swamp. Other families identified included the Scatophagidae, Ambassidae, Blennidae, Sciaenidae, Cynoglossidae, Scorpaenidae, Carangidae and Syngnathidae. Preliminary CCA suggests that salinity, turbidity and zooplankton size and abundance may be important factors regulating the distribution and abundance of fish larvae. However, its interpretation is cautioned due to the limited data. A larger data set is needed to correlate larval fish abundance with the environmental factors.

Migration, growth and feeding habit of John's snapper Lutjanus johnii and duskytail grouper Epinephelus bleekeri in Merbok mangrove brackish river

Wed, 01 Jan 2003 00:00:00 GMT

Migration, growth and feeding habit of John's snapper Lutjanus johnii and duskytail grouper Epinephelus bleekeri in Merbok mangrove brackish river Ogawa, Yasuki Ogawa, Yasuki; Ogata, Hiroshi Y.; Maeno, Yukio; Shimoda, Toru; Fujioka, Yoshimi; Fukuda, Yutaka This study was conducted to estimate the migration and population growth in total length and to observe the food organisms found in the stomach of John's snapper and Duskytail grouper. John's snapper and Duskytail grouper were caught monthly between October 2001 and September 2002 at the Merbok mangrove brackish river, Kedah, Japan. A total of 1308 John's snapper juvenile fishes with total length ranging from 61 to 238 mm were collected.

Actual conditions of marine capture fisheries and aquaculture of snappers and groupers in Malaysia

Wed, 01 Jan 2003 00:00:00 GMT

Actual conditions of marine capture fisheries and aquaculture of snappers and groupers in Malaysia Yahya, Saifulhak; Ogawa, Yasuki Ogawa, Yasuki; Ogata, Hiroshi Y.; Maeno, Yukio; Shimoda, Toru; Fujioka, Yoshimi; Fukuda, Yutaka This study was conducted to determine the long-term trend of marine catches and aquaculture production of snappers and groupers in Malaysia. All information on marine capture fisheries and aquaculture production of snappers (Lutjanidae) and groupers (Serranidae) were derived from the Annual Fisheries Statistics (1970-1999). In Peninsular Malaysia, the marine catches of snappers were at the lowest level since 1993 but aquaculture production was 2.3 times larger.

Preliminary study of the stomach contents of snappers and groupers of Pulau Sembilan coral reefs

Wed, 01 Jan 2003 00:00:00 GMT

Preliminary study of the stomach contents of snappers and groupers of Pulau Sembilan coral reefs Abdullah, Mohamed Pauzi; Ismail, Che Zulkifli Ogawa, Yasuki; Ogata, Hiroshi Y.; Maeno, Yukio; Shimoda, Toru; Fujioka, Yoshimi; Fukuda, Yutaka This study was conducted to determine the relationship between snappers and groupers in three habitats located at the coral reef areas of Pulau Sembilan group of islands between 26 July and 16 August 2002. The samples were collected using baited fish traps placed at the periphery of the reefs. Upon retrieving the traps, any grouper or snapper caught was separated from the rest of the catch and placed in chilled containers.