Dinamika Stok Ikan Mujair Sarotherodon Mossambicus Di Waduk Selorejo Yang Dijabarkan Dari Pendugaan Kelimpahan Stok Dengan Metoda Leslie

Waduk Selorejo yang terletak pada lintang 7° 53\u27 LS dan 112° 21\u27 BT dan luasnya 400 hektar, telah selesai dibangun pada tahun 1970.Waduk ini terbentuk karena terbendungnya aliran Kali Konto dan Sungai Kwayangan. Pada tahun 1973 waduk Selorejo secara tidak disengaja telah dimasuki ikan mujair (Sarotherodon mossambicus (Peters). Dominansi ikan mujair yang tertangkap, oleh Suwignyo (1973) dikatakan sebagai pencerminan meningkatnya populasi ikan tersebut.Fihak pengelola Waduk Selorejo telah melakukan penangkapan ikan dengan jaring insang secara berkala pada setiap malam minggu atau malam hari libur.Jenis USAha perikanan yang diusahakan penduduk adalah perikanan pancing.Terdapat juga penggunaan jala dan jaring tetapi jumlahnya tidak banyak karena kegiatan ini dilarang dilakukan di Waduk Selorejo

Beberapa Aspek Fekunditas Ikan-ikan Air Tawar Di Lubuk Limpam Sumatera Selatan I. Suku Bagridae, Kan Beringu Mystus Nigriceps C.v.

Studi aspek-aspek fekunditas ikan penting dilakukan karena hasilnya dapat digunakan untuk berbagai hal, antara Iain untuk mengetahui musim pemijahan, ukuran ikan pada saat produktif sebagai penghasil keturunan dan sebagai data masukan dalam proses pemilihan bibit dalam praktek-praktek budidaya ikan. Kegunaan lainnya adalah sebagai data penunjang dalam studi dinamika populasiikan, terutama dalam studi laju peremajaan stok.Penelitian pada ikan-ikan Mystus telah dilakukan antara lain pada Mystus nemurus, M. seenghala, M. gulio, M. aor dan M. bleekeri. Aspek-aspek yang diteliti umumnya mencakup segi-segi budidaya, tingkah laku pemijahan, tingkah laku makan, makanan dan aspek fekunditasnya (Arsyad 1973; Madsuly 1977; Saigal 1964; Saigal & Motwani 1961 dan Pandian 1966)

Distribusi Lokal Dan Spasial Punhus Binotatus Dan Rasbora Lateristriata Di Ci Taman Java Dan Ti Binua, Ujung Kulon

D.I. HARTOTO. 1986. Local and spatial distribution of Puntius binotatus and Rasbora lateristriata in Ci Taman Jaya and Ci Binua, Ujung Kulon. Berita Biologi 3(6): 261 - 267. A study of local and spatial distribution of the "beunteur" (Puntius binotatus) and the "paray" (Rasbora lateristriata) on two streams at the vicinity of Ujung Kulon National Park was conducted during dry (August 1983) and rainy season (January 1984).This study as a part of a sets of autecological studies, was aimed to reveal the differences of local and spatial distribution pattern of the two species. The results indicated that the pattern of distribution of paray were not significantly differed from beunteur, however, it was clearly shown that there are certain centers of local distribution for each species. It was also shown that the upstream segments were dominated by the beunteur and the downstream/segments by the paray. Observation on the spatial .distribution yield that the beunteur dominated the calm water habitat resources and paray occupied the rapidly moving water habitat resources.The possibilities of control mechanism of each pattern of distribution from time. to time;including inter and intraspecific competition, substrate preferences and others; were briefly discussed

Struktur Komunitas Gastropoda Dan Distribusi Spasial Melanoides Plicaria Di Cibinua Ujung Kulon

D.I. HARTOTO & RISTIYANTI M. MARWOTO.1986. Community structure and spatial distribution of Melanoides plicaria at Cibinua, Ujung Kulon. Berita Biologi 3(4): 155 - 158. The study was conducted during the dry and rainy seasons of the year 1983 and 1984, on upstream and downstream segment of Cibinua, Ujung Kulon National Park in order to reveal the pattern of distribution and corelation with its habitat structures.The gastropod community was dominated by M. plicaria and most the other species are found in only small number, which is in accordance with the published data of their genera distribution.Distribution of M.plicaria indicated a similar patchy pattern in all season and segment, but suspected due to different mechanisms.There is a clear individual packing phenomenon but do not distinctively shows an aggregation condition.Different corelation pattern between number of individuals per plot and weighted scores olphysical structure is found in all season and segment. Exclusive competition between the predo minant gastropod and the carnivorous and herbivorous fishes is briefly discussed

Pola Reproduksi Beberapa Jenis Cyprinidae Di Perairan Lebak Lebung, Lubuk Lampan, Sumatera Selatan

D.I. HARTOTO, SULASTRI & I. RACHMATIKA. 1985. Reproductive pattern of some Cyprinids species at Lebak Lebung flood plain area,Lubuk Lampan, South Sumatera. Berita Biologi 3(3): 128 - 135. -A study on reproductive characteristics of three Cyprinids species was conducted in Lubuk Lumpam; a floodplain area in South Sumatera during the early rainy season of 1981. A study of fecundity supported by other biological aspects was used as an approach to reveal the reproductive pattern. Analysis of the Osteochilus hasselti showed that the fish was an early and multiple spawner that strats to breed in a submerged vegetation habitat type before the peak of food abundance in the rainy season. All of the species could not be grouped as small brood spawners, including the least fecund fish Rasbora lateristriata that spawns late in its life span. Chela oxygasteroides showed a similar pattern to the two other species except that it was predicted to spawn during the time of food abundance. Based on Horn\u27s diagram, recapitulation analysis on factors of reproductive strategy indicated that three Cyprinids could be grouped as r - strategist

Tumpang Tindih "Niche" Ikan Di Muara Ci Siih Dan Ci Jaralang Selat Sunda Jawa Barat

D.I. HARTOTO, N. TRISNANINGSIH & I.RACHMATIKA. 1985. Fish niche of Ci Siih and CiJaralang estuaries, Sunda strait, West Java. Berita Biologi 3 (3) : 77 - 83. - A study of the fish community of Ci Silih and Ci Jaralang estuaries, Sunda Strait, West Java was conducted during the peak of dry season, August 1982. This study was aimed to apply Hutchinsonian niche theory into operational level and to reveal the stage of succession processes on the two estuarine fish communities.The study shows that type of refuges were more variate in Ci Jaralang than in Ci Siih and diversity of physical structure of spatial habitat resources affected a more diverse type of refuges. Means of absolute spatial niche breadth as a measure of concentration (?i) and uncertainty(?i) are larger in Ci Siih than in Ci Jaralang.Those facts indicate that fish species in Ci Siih were more dispersed in occupying the spatial habitat resources available. The larger (?i) value indicate that these two fish communities were still in early stages in their succession. The significantly similar means of absolute spatial niche overlap shows that the intensity of resources sharing on these two communities are nearly similar and are quite intensive

Pola Makan Dan Reproduksi Ikan Tor Spp. Sebagai Dasar Budidayanya

SULASTRI, I. RACHMATIKA & D.I. HARTOTO. 1985. Feeding and reproductive patterns of Torspp. as a base for its aquaculture. Berita Biologi 3(3): 84 -90. A study on the feeding and reproductive characteristics of Tor spp. as a base for aquaculture was done in laboratory and field conditions. Qualitative observation on the feeding habits of Tor douronensis (C.V.) do not show a restriction of the main diet to autochthonous sources. Algae were the main diet, followed by detritus, insects, diatoms, plant material, mosquitoes larvae and desmids. Laboratory observations show that T. douronensis eat first the food that is most concentrated, followed by the food that floats on the surface and last, foods on the bottom. Spearman Rank Correlation reveals that there was food overlaps between groups of fishes of different maturity stages from species collected in the field. It was found that there was a morphological change of male T. soro and a decrease of condition factors that were correlated with the increase of maturity stage. Vision as a significant factor affecting feeding and reproduction of Tor spp. and its relation to aquaculture application was discussed

Metals Bioconcentration of Freshwater Fishes in Central Kalimantan as an Evaluation Criteria for Management of Inland Water Fishery Reserve

Heavy metal bioconcentration was examined and evaluated in the muscle of several of freshwater fishes species collected from a complex of some oxbow lakes in Kahayan River and from Lake Sembuluh, Central Kalimantan. The objective of the study was to find natural background values of heavy metals in water, sediment and its biomultiplication factor related to their concentration in water and the fish position in the foodweb. In this analysis,one to twenty-five grams of fish muscle samples was obtained from the posterior part of pectoral but anterior to anal fins. Water samples, which were taken from surface and bottom layers of the lakes, were mix and preserved with nitric acid. Sediment samples were obtained by using Ekman Grab and the interstitial waters were extracted by using wet digestion technique.Iron concentration in fish muscle is the highest in omnivorous, followed by that of in carnivorous and detritivorous fish. Manganese, lead and mercury had different pattern of bioconcentration levels. Bioaccumulation factor for each metal and at each food habit category was also variable; the lowest value of 0.7 for iron in second consumer and 28.2 for mercury in primary consumer. Mechanism of heavy metal intrusion to fish muscle is very intricate and apparently depends upon feeding habit of each species. Concentration of mercury in water and fish muscle was far above minimum risk level, but concentrations of iron, manganese and lead in water and fish was considered still safe for environment as well as for human health. Potential utilization of these results as evaluation criteria for fishery reserve is discussed

Phytoplankton Changes in Some Inland Water Habitat of Central Kalimantan, Indonesia

The changes in the density, number of genera, diversity index of phytoplankton in some oxbow lakes (LakeRengas, Lutan,Takapan) and lowland lake (Lake Sembuluh) are described.Phytoplankton samples collected in rainy season, dry season (1995 to 1997) and in the forest fire period (October 1997).Before forest fire period, most of the time the density of phytoplankton was high (489 to 759 individuals/1) in January or rainy season especially in oxbow lake system. The high number of phytoplankton in rainy season is not common in the standing water in the floodplain system. This is probably because of the type of water that is acid water with the pH (4.43 to 4.66) in Lake Rengas, Lake Lutan (4.93 to 5.93) and Lake Takapan (4.03 to 4.64).In acid water oxbow lake, only some certain species occurred in the dry season. In January (rainy season),the inputs of water from main river increase the pH and presumably also nutrient, as shown by higher conductivity.In Lake Rengas, the highest density found in June that dominated by one genera (Oocystis).These facts probably because of phytoplankton input from the river Rungan that also show high density of the same species.It is also showed that the number the number of genera is also high in rainy season. Nonetheless of index diversity changes is not clear. In October 1997, when the forest fire period the density of phytoplankton and some genera as a group of Euglenophyceae increased.The highest density was found in Lake Sembuluh that range from 10,507 to 39,536 individuals/1.The phytoplankton density of Lake Rengas, Lutan and Takapan are 3,254, 1,414 and 9,019 respectively.The relationship of forest fire to the phytoplankton density is briefly discussed

STRUKTUR KOMUNITAS GASTROPODA DAN DISTRIBUSI SPASIAL MELANOIDES PLICARIA DI CIBINUA UJUNG KULON

D.I. HARTOTO & RISTIYANTI M. MARWOTO.1986. Community structure and spatial distribution of Melanoides plicaria at Cibinua, Ujung Kulon. Berita Biologi 3(4): 155 - 158. The study was conducted during the dry and rainy seasons of the year 1983 and 1984, on upstream and downstream segment of Cibinua, Ujung Kulon National Park in order to reveal the pattern of distribution and corelation with its habitat structures.The gastropod community was dominated by M. plicaria and most the other species are found in only small number, which is in accordance with the published data of their genera distribution.Distribution of M.plicaria indicated a similar patchy pattern in all season and segment, but suspected due to different mechanisms.There is a clear individual packing phenomenon but do not distinctively shows an aggregation condition.Different corelation pattern between number of individuals per plot and weighted scores olphysical structure is found in all season and segment. Exclusive competition between the predo minant gastropod and the carnivorous and herbivorous fishes is briefly discussed