HUBUNGAN PANJANG BOBOT DAN FAKTOR KONDISI IKAN TETET, Johnius belangerii Cuvier (PISCES: SCIAENIDAE) DI PERAIRAN PANTAI MAYANGAN, JAWA BARAT

Penelitian ini bertujuan untuk menetapkan hubungan panjang-bobot dan mengevaluasi faktor kondisi ikan tetet, Johnius belangerii Cuvier di perairan pantai Mayangan, Jawa Barat. Pengambilan contoh dilakukan sekali sebulan dari bulan Mei 2002 sampai April 2003. Sebanyak 2 403 ekor ikan tertangkap dengan menggunakan jaring insang bermata jaring 1.5 - 3 inci. Panjang total dan bobot ikan contoh berkisar masingmasing 71 – 225 mm dan 3 – 161 gram. Hubungan panjang-bobot adalah W = 2.453 x 10-6 L3.3023. Hasil ini menunjukkan bahwa hubungan panjang-bobot mempunyai korelasi yang tinggi (R2 > 0.939). Faktor kondisi relatif beragam dari 0.966 to 1.070. Ikan betina mempunyai kondisi lebih baik daripada ikan jantan.Kata kunci: hubungan panjang bobot, faktor kondisi, ikan tetet, perairan pantai. This study is aimed to determine length-weight relationship and to evaluate relative condition factor of belanger’s croaker, Johnius belangerii Cuvier in Mayangan. Fish collection was carried out monthly from May 2002 to April 2003. A total of 2 403 individual fishes were caught using gillnet with mesh sizes varying from 1.5 to 3 inches. The fish samples ranged from 71 – 225 mm in length and 3 – 161 g in weight. The length-weight relationship was W = 2.453 x 10-6 L3.3023. The results indicated that the length-weight relationship was highly correlated (R2 > 0.939). The relative condition factors of fish varied from 0.966 to 1.070, of which females were generally in better condition than the males.Key words: length-weight relationship, condition factor, belanger’s croaker, coastal waters

Aktivitas Pemijahan, Perkembangan Awal, dan Pertumbuhan Larva Ikan Pelangi Arfak dalam Kondisi Laboratorium: Studi Pendahuluan untuk Penangkarannya

Comprehensive information regarding the reproduction, early development, and growth of larvae is very important in the efforts of captive breeding and reintroduction of endangered fish species. One of the species that is starting to be threatened is the Arfak rainbowfish, Melanotaenia arfakensis which is already in the vulnerable category and its information is still relatively limited. Therefore, this study was conducted to describe the spawning activity, early development, and growth of the larvae of this rainbow fish species under laboratory conditions. Experiments on a laboratory scale were carried out in March-September 2017. The fish used came from the Nimbai Stream. A total of three pairs of individual males and females ranging in size from 46.5 to 60.1 mm were selected for treatment. However, only one pair was successfully observed spawning activity completely. Spawning takes place between morning and noon in three spawning periods. In each period, spawning lasts between 8 and 11 days. Between spawning periods takes 14 to 22 days. After fertilization, the eggs are attached with filaments to the spawning substrate and placed at a depth of 7.3-24.3 cm from the surface of the water. One group of eggs spawned consists of 78-116 eggs with a diameter range between 1.05 and 136 mm. The eggs hatch in a period of 4 to 10 days. The body length of the newly hatched larvae ranges from 4.13-4.40 mm and will reach a size of 7.85 mm with a survival rate of 48.1% after 41 days. The results of this study found several advantages from the characteristics of spawning and growth in the early stages that are useful for captive breeding efforts and reintroduction of this rainbowfish to their natural habitat. Thus, its population in the Prafi River system can be maintained.Informasi yang lengkap mengenai reproduksi, perkembangan awal, dan pertumbuhan larva menjadi sangat penting dalam upaya penangkaran dan reintroduksi spesies ikan yang terancam punah. Salah satu di antara spesies yang mulai terancam adalah ikan elangi Arfak, Melanotaenia arfakensis yang sudah berada dalam kategori rentan dan informasinya masih sangat terbatas. Oleh karena itu, penelitian ini dilakukan dengan tujuan untuk mendeskripsikan aktivitas pemijahan, perkembangan awal, dan pertumbuhan larva spesies ikan elangi ini dalam kondisi laboratorium. Percobaan dalam skala laboratorium dilaksanakan pada bulan Maret-September 2017. Ikan yang digunakan berasal dari Sungai Nimbai. Sebanyak tiga pasang individu jantan dan betina dengan kisaran ukuran 46,5 sampai 60,1 mm dipilih untuk perlakuan. Namun, hanya satu pasangan yang berhasil diamati aktivitas pemijahannya secara lengkap. Pemijahan berlangsung di antara waktu pagi hari sampai siang hari dalam tiga periode pemijahan. Dalam setiap periode, pemijahan berlangsung di antara 8 dan 11 hari. Antarperiode pemijahan membutuhkan waktu 14 sampai 22 hari. Setelah dibuahi, telur dilekatkan dengan filamen pada substrat pemijahan dan diletakkan pada kedalaman 7,3-24,3 cm dari permukaan air. Satu kelompok telur yang dipijahkan terdiri atas 78-116 butir dengan kisaran diameter di antara 1,05 dan 136 mm. Telur menetas dalam periode 4 sampai 10 hari. Panjang tubuh larva yang baru menetas berkisar 4,13-4,40 mm dan akan mencapai ukuran 7,85 mm dengan tingkat sintasan 48,1% setelah 41 hari. Hasil penelitian ini menemukan beberapa kuntungan dari karakteristik pemijahan dan pertumbuhan tahap awal yang bermanfaat untuk upaya penangkaran dan pelepasliaran ikan ini ke habitat aslinya. Dengan demikian, populasinya di sistem Sungai Prafi dapat tetap dilestarikan

The length-weight relationships and condition factor of an endemic

Marosatherina ladigesi is an endemic fish species in South Sulawesi and is famous as ornamental fish. However, the biological information of this species is still restricted. This research direct analyzes the length-weight relationships and condition factors of M. ladigesi. Sampling was held monthly from May 2018 to April 2019 in the Walanae Cenranae River Watershed, South Sulawesi. Fish samples were assembled by seine net. A total of 550 M. ladigesi were collected consisted of 227 fish in Camba River, 88 fish in Sanrego River, and 235 fish in Batu Puteh River. The length-weight relationship of male and female fish was W = 0,0002L2,74 and W = 0,00004L3,23 in Camba River, W = 0,0001L2,78 and W = 0,0001L2,92 in Sanrego River, W = 0,0001L2,88 and W = 0,00006L3,12 in Batu Puteh River, respectively. In Camba and Batu Puteh Rivers, the growth pattern of male and female fish were negative allometric and positive allometric, respectively. Conversely, the growth patterns of male and female fish in the Sanrego River were isometric. The condition factor fish in Sanrego River was lower than Camba and Batu Puteh River. These findings are valuable data for establishing a monitoring and conservation of this endemic species in its habitat

Utility of Batang Toru River (North Sumatra, Indonesia) for fishery activities of the local communities: a study on fisheries socioeconomic condition

Batang Toru River is a river that crosses several sub-districts in North Tapanuli and South Tapanuli Regency and has social and economic benefits for the community. This study aimed to determine the fisheries' socio-economic condition of the community around the river. Study was carried out in August 2019, on the communities around the river in five districts, namely Sipirok district (Luat Lobang and Aek Batang Paya Village), Marancar District (Marancar Julu, Pasar Sempurna, Simaninggir, and Huraba Village), Batang Toru District (Sipenggeng and Hapesong Baru Village), Muara Batang Toru District (Bandar Hapinis Village), and Simangumban District (Simangumban Jae Village). The data collected were analyzed descriptively. Based on the study, the local communities usually used the river for fishing, although fishing was not their main occupation. The fish caught were generally for their consumption or sold in the surrounding village

Development potential of native fish in Batang Toru Watershed, North Sumatra, Indonesia: discussion on the impact of dam development and aquaculture efforts

As one of the sizable rivers in the Sumatra region, the Batang Toru River is a habitat for various fish species, some of which are potential to be developed as cultured fish. This study was carried out in April, July, and October 2019 in the Batang Toru River watershed of South Tapanuli Regency, North Sumatra, to evaluate a potential development of the riverine fish for aquaculture development. The methods used were fisheries surveys and discussions with various communities and related agencies in the South Tapanuli Regency. The data obtained were presented descriptively. Based on the result of data analysis collected in the field, there were several potential fish species to be cultured in this study, including mahseer (Tor tambroides, T. tambra, Neolissochilus soro), catfish (Hemibagrus spp.), and eel (Anguilla bicolor). Some people in the area have also developed the culture of several fish species, such as mahseer and catfish. However, there has been no eel rearing until now, although some locations around the Batang Toru River are suitable for freshwater fish aquaculture activities

Reproductive aspects of the Japanese threadfin bream,

This study describes the reproductive biology of the Japanese threadfin bream, Nemipterus japonicus (Bloch, 1791) captured from the Southern Java Waters (FMA-RI 573). Fish monthly sampling collection was conducted from July to December 2022 at three fish landing ports: PPI Ciwaru, PPN Palabuhanratu, and PPI Binuangeun. Overall, 951 individuals consisting of 469 males (49.32%) and 482 females (50.68%), with a size range of 92-300 mm and a weight range of 10–344 g were collected. The sex ratio is balanced (1:1.10), with fecundity ranging from 10,079 to 82,650 eggs. The length at first maturity is 146 mm for males and 141 mm for females. The Japanese threadfin bream is a total spawner. Spawning occurs throughout the sampling period, with a peak in October-November. The length-based spawning potential ratio (LBSPR) measures the sustainability of fish stocks, indicating that Japanese threadfin bream in southern Java is in an overexploited condition

Reproductive biology of Indian mackerel,

Indian mackerel is a small pelagic fish with important economic value in Java Island. This study aims to analyze the reproductive characteristics and determine management recommendations for the Indian mackerel in the southern waters of West Java. Fish monthly sampling collection was conducted at three fish landing ports: PPI Ciwaru, PPN Palabuhanratu, and PPI Binuangeun from July to December 2022. A total of 1,038 fish samples, comprised of 582 males and 456 females, were examined. The sex ratio was unbalanced, with a value of 1:0.79. Gonadosomatic indexes ranged from 0.19-0.95 and 0.45-3.41 for males and females, respectively. The fish fecundity ranged from 27,027 to 87,837 eggs. The Indian mackerel is predicted to spawn every month, with a peak season in August, and performs a total spawner pattern. The Indian mackerel reached the size of the first maturity gonad at 198.5 mm and 197 mm for males and females, respectively. Management strategies for Indian mackerel in the southern waters of West Java include setting the catch size above the first mature gonad size (197 mm), the mesh size of gillnets above 1.5 inches, and limiting fishing activities during the spawning season (July, August, and September)