Judul: Ecobiology and stock dinamic as a base on management of endemic fish bonti-bonti (Paratherina striata Aurich) in Towuti Lake, South Sulawesi
Abstrak: Bonti-bonti (Paratherina striata), is one of endemic and vulnerable fish in Towuti and Mahalona Lake. It should be protected from decreasing of it population due to habitat quality decline and increasing of exploitation. The objectives of this research is to study the spatial and temporal distribution, growth potency (somatic and reproductive), and relationship between exploitation level and stock ability to recover as base management of the fish. This research was conducted in Towuti Lake, South Sulawesi from May 2006 to April 2007. Samples were collected at five stations using experimental gillnet sized 0.625, 0.75, 1.0, and 1.25 inches and bagan (dipnet). The results show that bonti-bonti is dispersing widely from lakeside to the middle of the lake. The highest abundance of the fish are in inlet with sand, gravel, and stone substrat. The highest temporal distribution of the fish abundance in November and December influenced by dissolved oxygen and high water level. The result of covarian and cluster analysis towards standard morphometric character, could be said that male and female at I, II, III, IV, and V stations is similar tendency or predicted from one fish population. Bonti-bonti is kind of partial spawner fish with peak spawning in May and November. Spawning site, nursery site, and feeding site of the fish are in inlet station. Recruitment of the fish each month with the peak estimated in September, October, and November. Growth pattern of male is Lt=20.05 [1-e-1.7(t+0.02)], while female is Lt=20.45 [1-e-2.0(t+0.01)]. Total length of male and female mature gonad (50%) were 16.78 and 14.61 cm, respectively. Pursuant to growth parameters value and matured fish (50%), growth potency of bonti-bonti is still in good condition. Exploitation level of bonti-bonti stock in Towuti Lake indication to over-fishing (male E=0.54 and female E=0.56). The increasing catch effort (unit/month) of bagan tend to reduce the catch productivity. Decreasing of ability of bonti-bonti stock to recover is not caused by the environmental variables, but caused by over exploitation activity.
Keyword: environmental variables, exploitation activity, catch productivity

Judul: Population of endemic fish butini (Glossogobius matanensis) in Towuti Lake, South Sulawesi
Abstrak: Butini (Glossogobius matanensis) is one of the endemic fish biodiversity in Towuti lake. This fish has been consumed and has an important economic value. Due to intensive exploitation the populations tend to decrease and therefore should be protected based on low genetic diversity, low growth rate and late gonadal maturation stage (GMS). This study was to analyze genetic diversity, several population parameters and aspects of reproduction. This research was conducted from may 2006 to April 2007 in Towuti lake using long line/salue based on depth of water (25, 50, 75, 100, 150 and 200 metre). The butini were distributed at various depth and most found at 100 metre deep. Statistical analysis between population showed no significant different within zonation and depth either morphometric or molecular data. Structure population based on length frequency data divided into 3 groups of length : 28.08, 34.12, and 40.45 cm which are appeared both in male and female groups. Another parameters are L􀂒 = 46.62 cm and growth coefficient (K) = 1.200 per year. The predicted maximum ages of male and female fish were 5 and 6 years old respectively. It was calculated the total exploitation rate (E) was 0.52 per year and recruitment in this fish occurred in November to January. Total butini caught was 2195 fish consisted of 1401 male and 794 female. From total male there were 1119 (50.98 %) immatured and 282 (12.80 %) matured. On the other hand from 794 female there were 494 (22.51 %) immatured and the rest 300 fish (13.67) matured. Observation of GMS resulted that GMS I and II were found in most of the samples, it is indicated that the fish caught during the research mostly young fish. Gonado Somato Index of samples was 0.55 %. To prevent the decreasing populations of endemic fish butini, some regulations such as limitation time of fish catch during spawning season in October.
Keyword: Gonadal Maturation Stage (GMS), North Sulawesi, Endemic Fish Biodiversity

Judul: Grup dan Homomorfisma Grup pada Rubik Revenge
Abstrak: Rubik cube is a kind of puzzle game. A player must arrange rubik sides, which have been disordered, back to the position where every side has the same colour. This paper does not focus on the settlement solution, but instead on proving the existence of a group homomorphism between rubik movement group and S96 symmetric permutation group in rubik revenge. Firstly, it has been proved that rubik movement set is a group. Then, it also has been proved that the M set, which contains numeric labels of 1 until 96 in cubinos sides, is S96 symmetric permutation group.
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