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Diversitas Ikan pada Ekosistem Terumbu Karang di Perairan Pulau Menjangan, Taman Nasional Bali Barat Hernowo, Rusman; Djumanto, Djumanto; Probosunu, Namastra
Biota Biota Volume 18 Nomor 1 Tahun 2013
Publisher : PBI Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (539.05 KB)

Abstract

Tujuan penelitian adalah mengkaji keragaman ikan-ikan karang dan mengetahui penutupan terumbu karang di perairan Pulau Menjangan, Taman Nasional Bali Barat. Penelitian dilaksanakan dari akhir bulan April sampai awal bulan Mei 2012 di perairan Pulau Menjangan. Jumlah stasiun pengamatan ditetapkan sebanyak 8 lokasi berdasarkan perbedaan habitat. Pengukuran kondisi lingkungan dan pengambilan sampel dilakukan dengan penyelaman pada kedalaman 3 dan 10 m. Jumlah dan jenis ikan yang berada pada jangkauan 2,5 m dari transek sepanjang 50 m disensus dengan metode Underwater Visual Census. Jenis ikan karang diidentifikasi secara langsung insitu. Jenis dan luas penutupan karang dicatat dengan metode Line Intercept Transect. Pencatatan jenis terumbu karang yang dilewati transek didasarkan pada bentuk pertumbuhan (lifeform), sedangkan luas penutupan terumbu karang menggunakan Lifeform Report. Data yang diperoleh dianalisis secarakuantitatif berdasarkan indeks biologis. Hasil dari penelitian diperoleh nilai indeks keanekaragaman ikan (H’) berkisar antara 0,8499–2,1360, keseragaman (E) antara 0,36–0,73 dan indeks dominansi (C) berkisar antara 0,163–0,647. Cacah individu ikan sebanyak 5753 ekor dari 62 genus yang berasal dari 32 suku, sedangkan kemelimpahan ikan (D) berkisar antara 0,756–2,680 ekor/m2. Jumlah individu dan suku ikan mayor dominan pada semua lokasi. Tutupan terumbu karang berada pada kisaran 0,66–67,34% yang dikategorikan pada kondisi sedang hingga baik.Kata kunci: keragaman, ikan, terumbu karang, Pulau Menjangan, Bali
Kondisi Terumbu Karang di Kawasan Taman Nasional Laut Kepulauan Seribu DKI Jakarta Seto, Drajad Sarwo; -, Djumanto; Probosunu, Namastra
Journal of Biota Biota Volume 19 Nomor 1 Tahun 2014
Publisher : PBI Yogyakarta

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Abstract

AbstractThe objective of this research was to determine the condition of coral reefs, namely the percentage of coral covered, species distribution, community structure of coral, and the environmental conditions surround the core zone, protection zone, tourism zone, and residential zone in Kepulauan Seribu Marine National Park DKI Jakarta. The research was conducted from 8 to 16 May, 2013. The data was collected from four zones and each zone was set up into two stations as a point observation, at the depth of 79 meters. The percentage of coral coverring was calculated by line intercept transect method, coral genera was counted and identified using the belt transect method. Coral data was analyzed qualitatively based on ecological index. The results showed that the coral covering was range from 7.25 to 68.93% as categorized from bad to good condition. The number of coral was found approximately of 5.523 colonies that consisted of 45 genera and 16 families. The most abundance of coral was Porites and Montipora with percentage of 19.7% and 16.69%, respectively. Coral diversity index was ranged from 1.61 to 3.07 as indicated of low to high. Uniformity index was ranged from 0.44 to 0.68, which was the community in stressful to labile situation. Dominance index (D) was ranged from 0.06 to 0.32 showing that coral dominance was absence.Keywords: Coral reef, cover, diversity, Kepulauan SeribuAbstrakPenelitian ini bertujuan mengetahui kondisi terumbu karang yang meliputi persentase tutupan, sebaran, struktur komunitas dan kondisi lingkungan di zona inti, perlindungan, pemanfaatan wisata, dan pemukiman di kawasan Taman Nasional Laut Kepulauan Seribu DKI Jakarta. Penelitian dilaksanakan dari tanggal 8 sampai 16 Mei 2013. Pengambilan data berada pada empat zona pengelolaan dan setiap zona ditetapkan sebanyak dua stasiun pengamatan pada kedalaman 79 meter. Persentase tutupan karang dihitung dengan metode Line Intercept Transect, genera karang dihitung dan diidentifikasi menggunakan metode Belt Transect. Data jenis karang yang diperoleh dianalisis kualitatif berdasarkan indeks ekologis. Hasil penelitian diperoleh persentase tutupan karang berada pada kisaran 7,2568,93% yang dikategorikan kondisinya buruk hingga baik. Jumlah karang dari seluruh stasiun penelitian sebanyak 5.523 koloni yang terdiri dari 45 genera dan 16 famili. Genus karang yang paling sering dijumpai adalah Porites dan Montipora dengan persentase kelimpahannya masing-masing 19,7% dan 16,69%. Nilai indeks keanekaragaman (H’) karang berkisar antara 1,613,07 yang tergolong rendah hingga tinggi. Indeks keseragaman berkisar 0,440,68 yang berarti komunitas dalam keadaan tertekan hingga labil. Nilai indeks dominansi (D) berkisar 0,060,32 yang menunjukkan dominansi karang tertentu tergolong rendah.Kata kunci: Tutupan, terumbu karang, keragaman, Kepulauan Seribu
ECONOMIC VALUATION OF MANGROVE RESOURCE IN BAROS COAST TIRTOHARGO VILLAGE SUB-DISTRICT OF KRETEK Djumanto, Tyas Ismi Tria lfhianty Suadi
Jurnal Kawistara Vol 4, No 2 (2014)
Publisher : Sekolah Pascasarjana UGM

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Abstract

The community project to plan mangrove in downstream of Opak-OyaRiver has attracted the growingof various socio-economic activities. The objective of the research is to calculate the total economicvalues of mangrove ecosystem. The study was conducted in BarosBantul Regency on September toOctober 2013. The numbers of 41 farmers, 10 fishers, 9 cattlemans and 34 tourists were interviewed tofind out the economic values of mangrove ecosystem. The study indicated the total economic benefits ofmangrove area was IDR168.744.141,67/ha/year, which consist of IDR19.756.491,67/ha/year for directbenefits, IDR132.017.160,00/ha/year for indirect benefits, IDR170.490,00/ha/year for optional benefitsand IDR16.800.000,00/ha/year for existence benefits. The indirect economic benefit of mangrove areawas higher. It shows that ecological functions of mangrove played a greater benefits and the action toconserve and expand the mangrove area are extremely needed. The sustainability of the mangrove andmanagement based on ecology might remain as appropriate way to do in the futur
Feasibility Study on the Profitability of Vannamei Shrimp Aquaculture on Coastal Area of Keburuhan Village, Purworejo Regency Djumanto, Djumanto; Ustadi, Ustadi; Rustadi, Rustadi; Triyatmo, Bambang
Aquacultura Indonesiana Vol 17, No 1 (2016)
Publisher : Indonesian Aquaculture Society (MAI)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (184.203 KB) | DOI: 10.21534/ai.v17i1.49

Abstract

Brackish water vannamei shrimp aquaculture in Keburuhan village of Purworejo Regency is one of the shrimp aquaculture activities developed since 2010. Shrimp aquaculture enteprises were done by local communities which use sandy land coated by plastic sheet with an area of 1000-4500 m2. Some farmers suffered losses due to lack of technical knowledge in shrimp aquaculture, environmental carrying capacity, ecological and economic feasibility. The aim of this study was to determine the general condition of vannamei shrimp aquaculture and shrimp farming feasibility. The study was conducted by field surveys, interviews and questionnaires to 30 farmers. The survey was conducted in May-June 2016 by purposive sampling of farmers who were members of a joint venture group of Minamulyo. The results showed shrimp pond size aquaculture area was varied, with a range of 1000-1500 m2, 1500-2000 m2, 2000-3000 m2 and 3000-4500 m2. An average fixed cost required for construction and operation of shrimp pond aquaculture was approximately IDR 6,620,934 to 12,606,666 million/plot/cycle shrimp production, while the variable costs of each cycle production ranged from IDR 45,876,733 to 78,861,666. The revenue and net profit varied according to pond size. The net gain for the smallest pond (1000-1500 m2) was IDR 48,702,332/plot/cycle, and the largest pond (3000-4500 m2) was IDR 58,131,666/plot/cycle. The shrimp farmers could recover the original investment incurred within a period of 4-6 months (one half cycles). Vannamei shrimp aquaculture in Keburuhan village of Purworejo regency brings a variety positive and negative impacts to the development of the economic, social and environment. Positive impact included increase of income and welfare of farmers, while the negative impact was a decline in the quality of the pond environment.
Utilization of Wastewater from Vannamei Shrimp Pond for Rearing Milkfish in Keburuhan Coast Purworejo Sub-District Djumanto, Djumanto; Ustadi, Ustadi; Rustadi, Rustadi; Triyatmo, Bambang
Aquacultura Indonesiana Vol 19, No 1 (2018)
Publisher : Indonesian Aquaculture Society (MAI)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (597.185 KB) | DOI: 10.21534/ai.v19i1.48

Abstract

Brackish water vannamei shrimp in the village of Keburuhan, Ngombol District of Purworejo Regency is one of the shrimp aquaculture activities developed since 2010. Shrimp farming enteprises is done by local communities which use the sandy soil coated plastic sheet with an area of 1000-4500 m2. There is a positive impact by increasing the income and welfare of farmers, but give negative effects in decline of surrounding pond environment. The shrimp farmers mostly disposed of wastewater directly into the sewers or the surrounding area. The wastewater of vannamei shrimp culture contains of uneaten feed and plankton that can be utilized to grow milkfish. The aim of this study was to determine the growth and feeding preferences for milkfish culture in wastewater reservoir of vannamei culture. The study was conducted from January to April 2017 by rearing of milkfish in earthen ponds of shrimp culture in wastewater reservoir. Wastes consist of feces and uneaten feed during shrimp rearing were siphoned and flowed into ponds wastewater reservoir. Milkfish juvenile with body length ranges from 9.3 to 9.7 cm and weight ranges from 3.4 to 6.9 g was introduced into three earthen ponds of 600 m2 each, with density of 6 individual/m2 in triplicate for 70 days. During the study, milkfish juvenile were not fed, but obtained wastewater from shrimp culture ponds. The wastewater from the shrimp ponds was siphoned and piped into a waste reservoir ponds every 3 days until shrimp harvesting. Fish samples of each pond as much as 40 individuals were taken biweekly and then measured the length and weight. Fish stomach was dissected and then digestive tract was taken to observe the species of plankton consumed. The results showed that milkfish could grow well in wastewater reservoir of shrimp culture. The average daily growth rate of length and weight of milkfish reached approximately 0.11 cm/day and 0.34 g/day, respectively. The length weight relationship of milkfish showed allometric growth pattern. The food type found in the intestinal was dominated by phytoplankton. Feed was dominated by genera of phytoplankton, which reach more than 99%. The most dominant of phytoplankton were Scenedesmus sp. (34.7%), then Crucigenia sp. (20.1%), followed by Cyclotella sp. (14.6%), and Clamydomonas sp. (7.5%) next Microcystis sp. (6.7%), while the other genera less than 4.2%. Further research is needed to determine the optimum density of milkfish to utilize wastewater of shrimp culture.
Diversitas Ikan pada Ekosistem Terumbu Karang di Perairan Pulau Menjangan, Taman Nasional Bali Barat Hernowo, Rusman; Djumanto, Djumanto; Probosunu, Namastra
Biota : Jurnal Ilmiah Ilmu-Ilmu Hayati Vol 18, No 1 (2013): February 2013
Publisher : Universitas Atma Jaya Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (539.05 KB) | DOI: 10.24002/biota.v18i1.259

Abstract

Tujuan penelitian adalah mengkaji keragaman ikan-ikan karang dan mengetahui penutupan terumbu karang di perairan Pulau Menjangan, Taman Nasional Bali Barat. Penelitian dilaksanakan dari akhir bulan April sampai awal bulan Mei 2012 di perairan Pulau Menjangan. Jumlah stasiun pengamatan ditetapkan sebanyak 8 lokasi berdasarkan perbedaan habitat. Pengukuran kondisi lingkungan dan pengambilan sampel dilakukan dengan penyelaman pada kedalaman 3 dan 10 m. Jumlah dan jenis ikan yang berada pada jangkauan 2,5 m dari transek sepanjang 50 m disensus dengan metode Underwater Visual Census. Jenis ikan karang diidentifikasi secara langsung insitu. Jenis dan luas penutupan karang dicatat dengan metode Line Intercept Transect. Pencatatan jenis terumbu karang yang dilewati transek didasarkan pada bentuk pertumbuhan (lifeform), sedangkan luas penutupan terumbu karang menggunakan Lifeform Report. Data yang diperoleh dianalisis secarakuantitatif berdasarkan indeks biologis. Hasil dari penelitian diperoleh nilai indeks keanekaragaman ikan (H’) berkisar antara 0,8499–2,1360, keseragaman (E) antara 0,36–0,73 dan indeks dominansi (C) berkisar antara 0,163–0,647. Cacah individu ikan sebanyak 5753 ekor dari 62 genus yang berasal dari 32 suku, sedangkan kemelimpahan ikan (D) berkisar antara 0,756–2,680 ekor/m2. Jumlah individu dan suku ikan mayor dominan pada semua lokasi. Tutupan terumbu karang berada pada kisaran 0,66–67,34% yang dikategorikan pada kondisi sedang hingga baik.Kata kunci: keragaman, ikan, terumbu karang, Pulau Menjangan, Bali
Kondisi Terumbu Karang di Kawasan Taman Nasional Laut Kepulauan Seribu DKI Jakarta Seto, Drajad Sarwo; -, Djumanto; Probosunu, Namastra
Biota : Jurnal Ilmiah Ilmu-Ilmu Hayati Vol 19, No 1 (2014): February 2014
Publisher : Universitas Atma Jaya Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (273.71 KB) | DOI: 10.24002/biota.v19i1.454

Abstract

AbstractThe objective of this research was to determine the condition of coral reefs, namely the percentage of coral covered, species distribution, community structure of coral, and the environmental conditions surround the core zone, protection zone, tourism zone, and residential zone in Kepulauan Seribu Marine National Park DKI Jakarta. The research was conducted from 8 to 16 May, 2013. The data was collected from four zones and each zone was set up into two stations as a point observation, at the depth of 79 meters. The percentage of coral coverring was calculated by line intercept transect method, coral genera was counted and identified using the belt transect method. Coral data was analyzed qualitatively based on ecological index. The results showed that the coral covering was range from 7.25 to 68.93% as categorized from bad to good condition. The number of coral was found approximately of 5.523 colonies that consisted of 45 genera and 16 families. The most abundance of coral was Porites and Montipora with percentage of 19.7% and 16.69%, respectively. Coral diversity index was ranged from 1.61 to 3.07 as indicated of low to high. Uniformity index was ranged from 0.44 to 0.68, which was the community in stressful to labile situation. Dominance index (D) was ranged from 0.06 to 0.32 showing that coral dominance was absence.Keywords: Coral reef, cover, diversity, Kepulauan SeribuAbstrakPenelitian ini bertujuan mengetahui kondisi terumbu karang yang meliputi persentase tutupan, sebaran, struktur komunitas dan kondisi lingkungan di zona inti, perlindungan, pemanfaatan wisata, dan pemukiman di kawasan Taman Nasional Laut Kepulauan Seribu DKI Jakarta. Penelitian dilaksanakan dari tanggal 8 sampai 16 Mei 2013. Pengambilan data berada pada empat zona pengelolaan dan setiap zona ditetapkan sebanyak dua stasiun pengamatan pada kedalaman 79 meter. Persentase tutupan karang dihitung dengan metode Line Intercept Transect, genera karang dihitung dan diidentifikasi menggunakan metode Belt Transect. Data jenis karang yang diperoleh dianalisis kualitatif berdasarkan indeks ekologis. Hasil penelitian diperoleh persentase tutupan karang berada pada kisaran 7,2568,93% yang dikategorikan kondisinya buruk hingga baik. Jumlah karang dari seluruh stasiun penelitian sebanyak 5.523 koloni yang terdiri dari 45 genera dan 16 famili. Genus karang yang paling sering dijumpai adalah Porites dan Montipora dengan persentase kelimpahannya masing-masing 19,7% dan 16,69%. Nilai indeks keanekaragaman (H’) karang berkisar antara 1,613,07 yang tergolong rendah hingga tinggi. Indeks keseragaman berkisar 0,440,68 yang berarti komunitas dalam keadaan tertekan hingga labil. Nilai indeks dominansi (D) berkisar 0,060,32 yang menunjukkan dominansi karang tertentu tergolong rendah.Kata kunci: Tutupan, terumbu karang, keragaman, Kepulauan Seribu
ECONOMIC VALUATION OF MANGROVE RESOURCE IN BAROS COAST TIRTOHARGO VILLAGE SUB-DISTRICT OF KRETEK Tyas Ismi Tria lfhianty Suadi Djumanto
Jurnal Kawistara Vol 4, No 2 (2014)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (429.511 KB) | DOI: 10.22146/kawistara.5668

Abstract

The community project to plan mangrove in downstream of Opak-OyaRiver has attracted the growingof various socio-economic activities. The objective of the research is to calculate the total economicvalues of mangrove ecosystem. The study was conducted in BarosBantul Regency on September toOctober 2013. The numbers of 41 farmers, 10 fishers, 9 cattlemans and 34 tourists were interviewed tofind out the economic values of mangrove ecosystem. The study indicated the total economic benefits ofmangrove area was IDR168.744.141,67/ha/year, which consist of IDR19.756.491,67/ha/year for directbenefits, IDR132.017.160,00/ha/year for indirect benefits, IDR170.490,00/ha/year for optional benefitsand IDR16.800.000,00/ha/year for existence benefits. The indirect economic benefit of mangrove areawas higher. It shows that ecological functions of mangrove played a greater benefits and the action toconserve and expand the mangrove area are extremely needed. The sustainability of the mangrove andmanagement based on ecology might remain as appropriate way to do in the futur
The use of otolith to determine age and spawning time of red devil Amphilophus labiatus [Gunther, 1864] in Sermo Reservoir, Yogyakarta Sitty Ainsyah Habibie; Djumanto Djumanto; Rustadi Rustadi
Jurnal Iktiologi Indonesia Vol 15 No 2 (2015): June 2015
Publisher : Masyarakat Iktiologi Indonesia (Indonesian Ichthyological Society)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32491/jii.v15i2.63

Abstract

The purpose of this study was to determine the age and spawning time of red devil (Amphilophus labiatus) based on the observation of the daily increment of otolith in juvenile fish. The sampling was conducted from October 2013 to March 2014. The juveniles were collected biweekly using a hapa net and scoop net. To determine the first formation of daily increment, the brood stock of tilapia (Oreochromis sp.) was spawned in captivity. A total of five larvae was taken every day from hatching day until the 18 days old, and then the larvae were taken every two days. Sagittal otoliths were collected by putting the larva into a 5.25% NaOCl solution. The left otolith was attached to the object glass using Bucherer cement, and then dropped with Canada balsam and closed by cover glass. The numbers of daily increment were observed by using a microscope with a magnification 100-400 X. The age was determined based on the number of daily increment plus the first time of ring formation. Spawning time was determined by back calculation of the sampling time, plus age and incubation period. The result showed that there were 130 individual juveniles collected ranged from 7.0 to 14.6 mm total length (TL). The formation of daily increment on 69 sagittal otolits was observed. The first sagittal increment was formed on the third day after hatching and the forming of the increment was daily. The ages of juvenile red devil were between 9-28 days old and majority of the larvae in 17 days. Red devil spawned coincided with the new moon phase and high intensity of rainfalls. Abstrak Penelitian ini bertujuan untuk menentukan umur dan waktu pemijahan ikan red devil berdasarkan jumlah lingkaran ha-rian pada otolit juwana ikan. Penelitian dilakukan dari bulan Oktober 2013 hingga Maret 2014. Pengambilan contoh ikan dilakukan tiap dua mingguan dengan menggunakan waring dan seser. Guna menentukan awal pembentukan ling-karan harian pada otolit, maka dilakukan pengamatan terhadap otolit larva ikan nila albino (Oreochromis sp.) hasil te-tasan. Sebanyak lima ekor larva diambil tiap hari sejak menetas hingga umur 18 hari, selanjutnya larva diambil tiap dua hari. Otolit sagitta diambil dengan cara merendam ikan menggunakan larutan NaOCl 5,25%. Otolit yang tertinggal se-lanjutnya direkatkan pada objek gelas menggunakan semen bucherer, dan ditutup menggunakan kanada balsam serta kaca penutup. Pengamatan jumlah lingkaran harian menggunakan mikroskop dengan pembesaran 100-400 kali. Umur larva ikan ditentukan berdasarkan jumlah lingkaran pada otolit ditambah waktu terbentuknya lingkaran pertama kali se-jak penetasan. Waktu pemijahan larva ikan diduga dengan perhitungan balik dari waktu sampling ditambah umur dan masa pengeraman. Hasil penelitian menunjukkan sebanyak 130 juwana ikan red devil dengan kisaran panjang 7,0-14,6 mm berhasil dikumpulkan dan sebanyak 69 otolit berhasil diamati. Pembentukan lingkaran pada otolit nila albino dimu-lai pada hari ketujuh setelah pemijahan atau hari ketiga setelah penetasan dan terbentuk secara harian. Juwana ikan red devil berumur 9-28 hari, yang didominasi oleh larva berumur 17 hari. Ikan red devil memijah setiap bulan dari November hingga Februari, bertepatan dengan bulan fase gelap dan curah hujan tinggi.
Dinamika populasi ikan belanak, Chelon subviridis (Valenciennes, 1836) di muara Sungai Opak - Yogyakarta Djumanto Djumanto; Mike Gustiana; Eko Setyobudi
Jurnal Iktiologi Indonesia Vol 15 No 1 (2015): Februari 2015
Publisher : Masyarakat Iktiologi Indonesia (Indonesian Ichthyological Society)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32491/jii.v15i1.72

Abstract

reenback mullet (Chelon subviridis) is the main species of fish catches in the estuary of Opak River Yogyakarta. The study of the population dynamics becomes important as a basis for fisheries management tools, so that mullet fish stocks can be utilized in a sustainable manner. The purpose of this study was to assess the population parameter of mullet in the area. Fish sampling was done biweekly from the middle of July 2012 to May 2013. Fish catching was done using gillnets wi-th various mesh size. All samples of mullet were collected and sexed, total length was measured using a metal ruler and weighted using digital scales. Length frequency data were analyzed using the software of FiSAT II to estimate the parameters of growth, mortality and recruitment. The results showed that, for the male mullet, VBGF growth parameters, namely L®, K, and to was 29.93 cm, 0.23 and -0.22, respectively. The total mortality, natural mortality and fishing mortality was 1.21, 0.69, and 0.52 per year, respectively, and the exploitation rate was 0.42. In the female, the VBGF growth parameters L ®, K, and to was 37.28 cm, 0.34 and -0.35, respectively. The total mortality, natural mortality and fishing mortality was 1.56, 0.84 and 0.72 per year, respectively, while the exploitation rate was 0.46. Recruitment patterns occur each year with peak spawning was estimated at the beginning and ending of the dry season. Abstrak Ikan belanak (Chelon subviridis) merupakan salah satu jenis ikan tangkapan utama di muara Sungai Opak, Yogyakarta. Kajian dinamika populasi menjadi penting sebagai dasar pengelolaan perikanan agar stok ikan belanak dapat dimanfaatkan secara berkelanjutan. Penelitian ini bertujuan untuk mengkaji parameter populasi ikan belanak di muara sungai tersebut. Pengambilan contoh ikan dilakukan setiap pertengahan bulan dari Juli 2012 hingga Mei 2013. Penangkapan ikan menggunakan jaring insang berbagai bukaan mata jaring. Semua contoh ikan belanak yang tertangkap diidentifikasi jenis kelaminnya melalui pembedahan, diukur panjang total menggunakan mistar logam dan berat individu menggu-nakan timbangan digital. Data frekuensi panjang dianalisis menggunakan perangkat lunak FiSAT II untuk menduga parameter pertumbuhan, mortalitas dan rekrutmen. Hasil penelitian pada belanak jantan menunjukkan parameter pertum-buhan VBGF L®, K, dan to adalah 29,93 cm, 0,23 dan -0,22; mortalitas total 1,21 per tahun, mortalitas alami 0,69 dan mortalitas penangkapan 0,52 per tahun serta tingkat eksploitasi sebesar 0,42. Pada belanak betina diperoleh parameter pertumbuhan VBGF L®, K, dan to adalah 37,28 cm, 0,34 dan -0,35; mortalitas total 1,56 per tahun, mortalitas alami 0,84 dan mortalitas penangkapan 0,72 per tahun serta tingkat eksploitasi sebesar 0,46. Pola rekrutmen terjadi setiap tahun dengan puncak pemijahan diperkirakan pada awal dan akhir musim kemarau.