Marine Research in Indonesia (MRI - E-Journal)
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MACROBENTHIC COMMUNITY STRUCTURES OF THE OFFSHORE AREA OF MIMIKA DISTRICT, PAPUA
No full textThe study on macrobenthic community structures was carried out in the offshore area of Mimika district, Papua in 2005. Steep mountain slopes and some of the highest rainfall rates in the world, have generated tremendous sediment loads that have settled in the alluvial plain and been carried out into the estuaries and the Arafura Sea, creating a massive area of deposited natural sediments. The objective of this study was to determine how the benthic community structures of the offshore area (Arafura Sea) changes as a result of environmental conditions. To accomplish the objective, samples were collected from 40 stations which were divided into 4 contours (layers) of water depth, i.e. 5, 10, 20 and 40 m. Stations of each contour depth were established perpendicular to the river mouths of Mimika district. The results showed the bottom sediments were mostly silt-clay fractions except the deeper area (40 m depth) which was dominated by very fine sand fraction. Diversity indices, Shannon index (H') and Pielou's evenness (e) index ranged from 1.00-3.50 and 0.20-0.92 respectively. These indices tended to increase in the deeper areas. In total 266 species of macro-benthos were collected from the study area. Contrary to this, the densities tended to decrease in deeper areas with the range of 195.00 — 4110.00 individualsm-2. Polychaetes was the the dominant group, 50.80 — 71.80 % of the total family of macrobenthos. Among the macrobenthos, there were some families and group of taxa which had high densities such as Sipuncula, Nemertea and crustaceans including Ampeliscidae, Gammaridae and Israeidae. Among the polychaete group were the families Spionidae, Owenidae, Sternaspidae, Cossuridae, Capitellidae, Nephtyidae, Magelonidae and Pilargidae. Based on density, macrobenthos of the study area shows relatively high production. High rates of sedimentation of Ajkwa estuary does not influence the structure of macrobenthic communities in the offshore area
SPIDER CRABS OF THE GENERA PARATYMOLUS MIERS, 1879 AND LITOSUS LOH & NG, 1999 FROM LOMBOK ISLAND, INDONESIA (CRUSTACEA, DECAPODA, BRACHYURA, MAJOIDEA, INACHIDAE)
No full textA small collection of majoid spider crabs of the genus Paratymolus Miers, 1879, s.l from Lombok Island, Indonesia contains four species namely P. hastatus Alcock (1895), P. coccus Loh & Ng (1999), P. cygnus Loh & Ng (1999), and Litosus sexspinosus (Miers, 1884). Except for L. spinosus, the three other species are new records for Indonesia. Paratymolus coccus is previously known from only female specimens, and the presence of male specimens in the collection studied provides the opportunity to complete the description of male characters. Paratymolus hastatus is reported for the first time outside Indian Ocean and P. cygnus is recorded for the first time after its description
FIRST RECORD ON ODONTANTHIAS FLAGRIS YOSHINO AND ARAGA, 1975 (PERCIFORMES: SERRANIDAE) IN INDONESIAN WATERS
No full textTwo specimens of Odontanthias flagris have been caught from Bitung, North Sulawesi in June 2010. Previously, nown locations of this species are Okinawa and Nishino-shima, Japan. O. flagris is very similar with O. rhodopeplus. They shares following characters: dorsal fin rays X, 13; anal fin rays III, 7; pectorals fin rays 17-18; scales above lateral line 7; scales below lateral line 19 and gill rakers on lower limb 28. Characters differing O. flagris from O. rhodopeplus, O. chrysostictus and other six species appear in the percentage of orbit diameter. In addition, O. flagris has shorter pelvic fin rays but longer caudal peduncle and third dorsal fin spine. Its morphological features, distribution, remarks and photo of species are given in this paper
SPECULATION CONCERNING SPECIATION IN CORAL REEF FISHES
No full textThe relatively constant equatorial marine environment provides a milieu within which biotic factors provide the chief selective forces acting on fish species. Increasing diversity increases evolutionary opportunity by heterotrophic magnification. Niche availability is almost limitless, space (volume) is the ultimate constraint. Abiotic thresholds, e.g., seasonal isotherms, are filter barriers to emigration to higher latitudes. Beyond such thresholds, abiotic, factors become the chief selective forces acting on fish species
ECOLOGY AND MANAGEMENT OF AN ESTUARY AT THE EDGE OF THE AMERICAN CARIBBEAN: BISCAYNE BAY
No full textBiscayne Bay is a shallow subtropical estuary, 225 square miles of water, at the edge of the tropics, located within Dade County, one of the fastest growing counties in the U.S.A. The fragility of this seagrass and mangrove dominated estuary has been demonstrated by repeated destruction of these ecosystems by man's activities, such as dredging, filling, drainage, sewerage, thermal pollution, and others. At the southern end, the U.S. Department of the Interior has recently established the Biscayne Monument, a preserve area where fairly rigit restrictions for man's use of the biota are enforced. At the northern end, intense land development since 1910 along with establishment for artificial islands and causeways, bulkheading, sewerage outfall and other pollutants has altered the ecology greatly. Approximately 1.5 million people inhabit this area. Multiple authorities for regulating use in the bay and its shoreline exist ranging from county to Federal. Many problems of overlapping jurisdiction and enforcement occur. Two symposia to bring together the knowledge of processes occurring m the bay and to delineate a policy for managing the bay were held in March 1976 resulting in the Volume, Biscayne Bay: Past, Present, and Future. Aspects of the ecology of this bay and of the management problems and goals will be discussed
THE EXPLOITATION OF THE ESTUARIES IN THE KENDAL AREA (NORTHERN COAST OF JAWA) BY ARTISANAL FISHERMEN
No full textThe estuaries at the northern coast of Jawa are good fishing grounds for the artisanal fishermen. They have been exploited heavily, and is becoming more so with the advance of technology in the form of motorized vessels. Does the exploitation provide a good livelihood to the fishermen? The outcome of the preliminary analysis of the fishing activities of artisanal fishermen in the Kendal area (Central Jawa) will be presented, the problems discussed
PELAGIC ENVIRONMENT IN THE WESTERN PART OF JAKARTA BAY
No full textSeven stations in the western part of Jakarta Bay were occupied monthly from June 1974 to June 1975. Monthly variations of several hydrological and biological properties of the pelagic environments are described. Rainfall over the hinterland of Jakarta plays important role in lowering the salinity in the bay. On the other hand the phosphate content is more closely associated with the rainfall over Jakarta. The main source of phosphate is likely to come from the result of urban activities in Jakarta. There is a fair corespondence in annual fluctuation between phosphate and phytoplankton chlorophyll. Annual mean of properties at each station shows that from the shore outward the values of phosphate, phytoplankton chlorophyll, and zooplankton volume decreased while of salinity and transparency increased. Interrelationships among several factors are discussed
PRELIMINARY STUDY ON THE DISTRIBUTION OF THE AEROBIC HETEROTROPHIC BACTERIA AND THE MICROBIAL INDICATORS IN JAKARTA BAY
No full textThe distribution of heterotrophic bacteria and microbial indicators in the Jakarta Bay were studied. Higher frequency of occurrences of the total coliform were observed in water samples collected near rivermouths or in the vicinity of islands. Lower frequency of occurrences of total coliform were obtained from samples collected from the far northern side of the Bay. The isolated strains belong to the genera Achromobacter, Vibrio, Flavobacteria, Micrococcus and coliforms. Micrococcus and coliforms were mostly obtained from samples collected at stations which are suspected to be highly influenced by human activities. The presence of Vibrio parahaemolyticus-like organisms were also determined. Occurrences of the genera varied unpredictably but were mostly within the six genera mentioned
SEASONAL VARIATIONS OF CERTAIN MAJOR ZOOPLANKTON GROUPS AROUND PANGGANG ISLAND, NORTH-WEST OFF JAKARTA
No full textSeasonal and annual variations of the composition of zooplankton in the water around Panggang Island were studied from May 1971 to April 1973. Temperature and salinity of the water and the abundance of zooplankton were assumed to be affected by the monsoon. It was usually found that the abundance of zooplankton in this area coincided with or occurred after the heavy rainfall. The occurrence of many zooplankton groups in each season did not greatly change, but the intensity of total number were vary in certain groups. The pattern of the annual variation of the zooplankton number was nearly regular in the two years of investigations. The major groups of zooplankton observed during this investigations were also discussed. In general the zooplankton of the water of Panggang Island were typically neritic. Some bigger species of copepods were even less than in the Java Sea
THE ALPHEID SHRIMP OF INDONESIA, BASED UPON J.G. DE MAN'S "THE DECAPODA OF THE SIBOGA EXPEDITION, PART II. FAMILY ALPHEIDAE." (1911)
No full textWe wish not only to up-date the taxonomy used by DE MAN in his 1911 study but also to add to his list of species those new records of species from Indonesia based, upon collections made subsequently by various individuals and agencies. DE MAN reported that he had 113 species and 20 varieties of these shrimp from the Siboga Expedition; of these, 54 species and varieties have been reduced to synonymy in the subsequent years. In the present study these additional species are also being so reduced:Alpheopsis hummelinki SCHMITT (= Neoalpheopsis euryone (De Man)Neoalpheopsis hiatti BANNER (= N. euryone De Man) Synalpheus jedanensis De Man (= S. iphinoe De Man) S. miscellaneus De Man ( = S. neomeris (De Man) S. physocheles Coutiere (= S. triunguiculatus (Paulson) S. sluiteri De Man (= S. paraneomeris Coutiere) S. stimpsonii var. maldivensis C outiere (= S. stimpsonii ( De Man) S. streptodactytoides De Man (=S. streptodactylus Couti>re)From the post-Siboga collections, we list an additional 28 established species from Indonesian waters as well as two new species: Alpheus nipa and Synalpheus mortenseni; we also have reviewed the status of Alpheus (= Synalpheus) tricuspidatus Heller (1861) and consider it to be a nomen dubium. We now recognize a total of 145 species from Indonesian waters plus an additional 2 species left unnamed by De Man and by us