Struktur Komunitas Lamun Di Perairan Pesisir Manokwari

The study was done from July to October 2007 by line transect method, plots, and exploration survey. There were eight species found in this study were grouped into pioneer group (Cymodocea rotundata, Halodule pinifolia, Halodule uninervis, Halophila ovalis, Syringodium isoetifolium) and climax (Cymodocea serrulata, Enhalus acoroides, Thalassia hemprichii), with mixed vegetations. Density, covering percentage and biomass in Andai and Wosi were dominated by H. pinifolia; Rendani and Tj. Mangewa were dominated by T. hemprichii; and Briosi were dominated by C. rotundata and T. hemprichii. INP in Andai and Wosi (dominated by H. pinifolia) were 290.005 and 243.767, respectively; Rendani and Tj. Mangewa (dominated by T. hemprichii) were 101.725 and 135.139, respectively; and Briosi (dominated by C. rotundata) was 120.146. The highest ratio of above and below biomass was found in Andai (7.831) and the lowest was found in Briosi (2.103). Seagrass community in Rendani, Tj. Mangewa and Briosi had higher biodiversity index than Wosi and Andai (0.109 and 0.015). On the other hand, Rendani, Tj. Mangewa, and Briosi had lower dominance index (0.262, 0.421 and 0.338, respectively), compared to Andai (0.989) and Wosi (0.889). Level of similarity among seagrass community in Rendani, Briosi and Tj. Mangewa was categorized as very high (92.31 %), while Andai and Wosi was high (66.67 %)

KEPADATAN, KARAKTER MORFOLOGI, DAN PERTUMBUHAN LAMUN Cymodocea rotundata DI PANTAI YANKARWAR, MANOKWARI, PAPUA BARAT: APAKAH ADA PERBEDAAN DIANTARA ZONA INTERTIDAL?

Cymodocea rotundata is a seagrass species that occupy habitats in the intertidal zone. The ability of this species to occupy the intertidal zone is thought to be related to its particular morphological adaptations in response to fluctuations in local aquatic environmental conditions. This study aims to describe habitat conditions, distribution related to density, morphological differences, and growth among C. rotundata seagrass stands in the upper, middle, and lower intertidal zones of Yankarwar Beach, Manokwari, West Papua. Transects and quadrats methods were used to collect seagrass samples, so information on their distribution and density could be obtained. The seagrass samples collected were also analyzed (counted and measured) for their morphological characters including the number of leaves, leaf length, leaf width, horizontal sheath internode length, root length, stand weight, leaf weight, rhizome weight, and root weight. Seagrass growth was obtained by marking the leaves and observing them for 10 days. The results of this study indicate that the conditions of the physicochemical parameters of the intertidal waters are still suitable for the growth of this seagrass species. The highest density was found in the upper intertidal zone (3,161.73 stands.m-2) and followed by the middle intertidal zone (962.04 stands.m-2). Although most of the morphological characters of seagrasses and seagrass parts were relatively the same between the three intertidal zones, larger leaf widths and lengths of horizontal rhizome internodes were found in stands in the two upper intertidal zones. Differences in growth as reflected by the increase in leaf length and dry leaf weight also showed greater values in the upper and middle intertidal zones. This condition shows the adaptability of this seagrass species to variations in environmental parameter conditions in the middle and upper intertidal zone. In addition, the results of this study indicate the presence of C. rotundata, especially in the intertidal aquatic environment which has an important ecological role, including as a substrate stabilizer. Therefore, this vegetation conservation effort is very important.   Keywords: intertidal zone, morphological adaptation, seagrass growt

Biologi Reproduksi Ikan Kiper, Scatophagus argus (Linnaeus, 1766) di Teluk Pabean, Indramayu

The spotted scat, Scatophagus argus (Linnaeus, 1766) is a component of the estuarine ecosystem with little reproductive information. Therefore, this study was conducted with the aim of describing aspects of the reproductive biology of this fish species through sex ratio, size at first sexual maturity, and spawning season. The collection of fish samples from the waters of Pabean Bay was carried out every month between January and December 2015. The fishing gear used were sero and gill nets. A total of 428 individuals were collected consisting of larval, juvenile, pre-adult, and adult stages. The ratio of the number of male and female individuals is relatively balanced (1.00 : 1.05). The size of the male individual's first sexual maturity at a total length of 102.95 mm and 112.44 mm in female individuals. The composition of gonadal maturity level and gonadal maturity index value indicated that there was reproductive activity that lasted throughout the year and increased in January-February and September-November. Information on reproductive aspects obtained in this study can be used as a basis for the management of this fish resource, including through recommendations for closing locations and fishing times.Ikan kiper, Scatophagus argus (Linnaeus, 1766) adalah salah satu komponen pada ekosistem estuari yang masih sedikit informasi reproduksinya. Oleh karena itu penelitian ini dilakukan dengan tujuan untuk mendeskripsikan aspek biologi reproduksi jenis ikan ini melalui rasio kelamin, ukuran pertama kali matang kelamin, dan musim pemijahan. Pengumpulan contoh ikan yang berasal dari perairan Teluk Pabean dilakukan setiap bulan di antara Januari dan Desember 2015. Alat tangkap yang digunakan adalah sero dan jaring insang. Sebanyak 431 individu berhasil dikumpulkan yang terdiri atas tahap larva, yuwana, pradewasa, dan dewasa. Perbandingan jumlah individu jantan dan betina relatif seimbang (1,00 : 1,05). Ukuran pertama kali matang kelamin individu jantan pada ukuran panjang total 102,95 mm dan 112,44 mm pada individu betina. Komposisi tingkat kematangan gonad dan nilai indeks kematangan gonad menunjukkan adanya aktivitas reproduksi yang berlangsung sepanjang tahun dan meningkat pada Bulan Januari-Februari dan September-November. Informasi mengenai aspek reproduksi yang diperoleh dalam penelitian ini bisa menjadi dasar dalam pengelolaan sumberdaya ikan ini, di antaranya melalui rekomendasi untuk penutupan lokasi dan waktu penangkapan