Feeding problems in early larval stage of the white blotched snapper, Lutjanus Rivulatus

Nguang , Siew Ing (2007) Feeding problems in early larval stage of the white blotched snapper, Lutjanus Rivulatus. Masters thesis, Universiti Malaysia Sabah.

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Abstract

Efforts were made to produce the seeds of Lutjanus rivulatus in the Marine Hatchery of Borneo Marine Research Institute, Universiti Malaysia Sabah (UMS Hatchery). The larvae showed a high mortality rate in the 10 days after hatching (dAH). This study was conducted to investigate the causes of high mortality and to observe the early larval development of L. rivulatus, in order to obtain information to improve the larval rearing techniques of L. rivulatus. Fertilized eggs were collected from the brooc1fish tank and were placed in the incubation tank. The newly hatched larvae were cultured with density 90,000 tails in 1-tonne tank and fed with algae, Nannochloropsis sp. (0.5 million cells/mL) and rotifer, Brachionus sp. (20 rotifer/mL). From 0 to 72 hours after hatching (hAH), the larvae were sampled every 6 hours and fixed in Bouin solution for histology and Kamosky's solution for scanning electron microscope observations. The larvae from 3 to 10 dAH were sampled everyday by the same solution. The total length (TL), body height, yolk sac length, and oil globule diameter of larvae were measured. L. rivulatus larvae (2.19+0.09 mm in mean TL) hatched with unpigmented eyes, no taste bud and unopened olfactory pits. The mouth was not opened and the anus was not formed. A pair of free neuromasts with cupulae was found behind the eyes and the larvae were suspended head down in the water column. At 42 hAH, the larvae (3.09+0.06 mm in TL) were sufficiently morphological develop to be fed and the volume of the yolk sac left was 0.0013 mm3 (99% of yolk sac volume had been absorbed). The larvae had deeply pigmented eyes, opened mouth (80 11m) with moveable lower jaw, opened anus with movable intestine and demonstrated horizontal movement and S-posture for feeding. It was found that L. rivulatus larvae have only an 18-hours nutritional transition period, which is considered shorter than many other species such as Lates calcarifer, and because of their minute mouth, they are unable to ingest S-type rotifer (150-230 µm). From these results, it is suggested to start feeding the larvae at 42 hAH with starter feed of less than 80 11m to avoid death of larvae due to starvation.

Item Type:Thesis (Masters)
Uncontrolled Keywords:Lutjanus rivulatus, Marine Hatchery, IPMB, larvae, starvation, White Blotched Snapper
Subjects:Q Science > QL Zoology
Divisions:SCHOOL > Borneo Marine Research Institute
ID Code:6882
Deposited By:IR Admin
Deposited On:12 Sep 2013 13:51
Last Modified:12 Sep 2013 13:51

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