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ABUNDANCE OF DIATOM AT THE GUMILAMO AND MAGALIHO ISLAND, NORTH HALMAHERA Rina Puji Astuti; Philip Teguh Imanto; Gede S. Sumiarsa
Jurnal Ilmu dan Teknologi Kelautan Tropis Vol. 4 No. 1 (2012): Elektronik Jurnal Ilmu dan Teknologi Kelautan Tropis
Publisher : Department of Marine Science and Technology, Faculty of Fisheries and Marine Science, IPB University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (196.859 KB) | DOI: 10.29244/jitkt.v4i1.7810

Abstract

Observation on abundance of diatom has been conducted in Gumilamo-Magaliho waters, North Halmahera. The aims of this study were to identify and analyze daily fluctuations of diatom abundance also analyze the biological indices in the plankton in that waters and . Sampling was conducted at three stations representing the strait, mangrove areas and estuary. Plankton were collected using a plankton net no.25. Sampling was carried out for 24 hours with six hour interval. Identification and counting of cells using a microscope with 400x magnification. The results showed that seven genera of diatoms were found: Chaetoceros sp. with the highest of cells abundance (5.061 cells/L), successively followed by Nitzschia sp. (611 cells/L), Thalassionema sp. (569 cells/L), Skeletonema sp. (446 cells/L), Coscinodiscus sp. (176 cells/L), Navicula sp. (40 cells/L) and Amphora sp. (11 cells/L). At station I and II showed that the maximum abundance occurred at 6 am, and the minimum abundance occurred at 6 pm. At station III the maximum abundance occurred at midnight and a minimum abundance occurred at noon. Diatoms showed different daily fluctuations at different time and stations. The supporting diversity index value of medium, low uniformity, and no dominance factor causing the Gumilamo-Magaliho waters can be developed for aquaculture.Keywords: diatom, diatom abundance
PLANNING ON HATCHING TIME OF GROUPER EGGS THROUGH DIFFERENT INCUBATION TEMPERATURES Regina Melianawati; Philip Teguh Imanto; Made Suastika
Jurnal Ilmu dan Teknologi Kelautan Tropis Vol. 2 No. 2 (2010): Elektronik Jurnal Ilmu dan Teknologi Kelautan Tropis
Publisher : Department of Marine Science and Technology, Faculty of Fisheries and Marine Science, IPB University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (112.661 KB) | DOI: 10.29244/jitkt.v2i2.7855

Abstract

Groupers were known as a high economically marine commodity and in order to support groupers production, the seed availability was the most important. Eggs are still as limited factor in hatchery production, for this reason the success of eggs transportation is one as base of successful production of seed. Planning on hatching time of eggs through different incubation temperature was an option to solve that problem. This experiment was aimed to find out the optimum temperature for groupers eggs and the minimum temperature to arrange incubation time and to plan the hatching time. Fertilized eggs were incubated into three beaker glasses of 1 liter in volume with the density of ± 250 eggs/liter. The incubation was done under laboratory condition at controlled temperature, i.e. (A) 21-22 ºC, (B) 24-25 ºC, (C) 27-28 ºC and (D) 30-31 ºC. The eggs that used were including orange spotted grouper (Epinephelus coiodes), brown marbled grouper (E. microdon), tiger grouper (E. fuscoguttatus) and humpback grouper (Cromileptes altivelis). Investigated variables were embryonic development pattern, incubation time and hatching rate. The result showed that the eggs incubated in temperature range of 24-31°C had the normal sequence of embryonic development pattern, but in temperature of 21-22°C performed irregular sequence and the embryonic development stopped at blastula or gastrula stage or even the eggs could still develop but the body of hatched larvae were abnormal. In lower temperature incubation, the incubation time was longer and the hatching rate of eggs was lower than those in higher temperature. Therefore the optimum temperature for incubation of orange spotted grouper, marbled grouper, tiger grouper and humpback grouper eggs ranged between 24-31 ºC, while the lowest possible temperature was 24 ºC.Keywords: incubation temperature, embryonic development pattern, grouper eggs, hatching rate