ABUNDANCE AND BIOMASS ESTIMATES OF COMMERCIAL FISH SPECIES USING HYDRO-ACOUSTIC METHOD IN JAKARTA BAY, INDONESIA

The Jakarta Bay is known as a fishing ground area for several traditional types of fishing gears. The fishery has important role to provide nutrition, sustainable livelihoods, and poverty alleviation around the area. Abundance estimation of commercial fish species in the Jakarta Bay is essential particularly comparable of series data in order to evaluate the potential changes in distribution and abundance. The purpose of this study is analyzing the distribution of commercial fish species in the Jakarta Bay and estimate their abundance and biomass. Fish assemblages were concentrated in the eastern and central part of bay. Apparently salinity and DO associated with rich density of phytoplankton and zooplankton may explain the spatial variability of short-bodied mackerel and pony fish, while assemblages pattern of spiny hairtail and croaker might be driven by the availability of small planktivorous fish as their diet. The most abundant commercial fish in the Jakarta Bay are Short-bodied mackerel (Rastrelliger brachysoma), Ponyfish (Leiognathus sp.), Croaker (Johnius sp.) dan Spiny hairtail (Lepturacanthus savala) respectively. Furthermore, biomass estimates for those species showed short-bodied mackerel has the highest biomass followed by spiny hairtail, croaker, and ponyfish

POTENTIALS YIELD AND FISHERIES OF MALAHAYU RESERVOIR, BREBES

Fishing activity in Malahayu Reservoir has been done since long time. Unlimited fishing may impact to the decresing of fish resources of those waters. This study presents an assessment of fishing practices in Malahayu reservoir between 2008-2016 periods. Data of potential fish production and catch per unit effort were estimated by using different estimate models, catch per unit effort was analyzed annually, while potential fish production was analyzed by using five models namely model by Henderson & Welcome (1974), Teows & Griffith (1979), Marshal (1984), Moreau & De Silva (1991) and Crul (1992). The results show that changes of fish composition has accured, which was originally dominated by native fish while for now it is dominated by 72,05% of tilapia (Oreochromis niloticus) as an introduced fish. Furthermore, the average catch per unit effort (CPUE) in Malahayu reservoir is about 11,82 kg / fisherman, while the average potential production is about 198,55 kg / year. CPUE value and potential production indicate that exploitation rate in Malahayu Reservoir are in fully-exploited or perhaps over-exploited condition. Related to those conditions, not to increase the number of efforts (fishermen) as a management option towards sustainable fisheries

STATUS OF SMALL PELAGIC FISHERY IN THE MAKASSAR STRAIT BASED AT THE NORTHERN PART OF JAVA

The coastal of Makassar Strait is one of main fishing grounds for purse seine vessels from northern part of Java which based at the following landing sites, i.e. Pekalongan, Tegal and Juwana. The purse seine fishery predominantly targets small pelagic fish. This paper attempts to present the current condition of small pelagic fishery in the Makassar Strait. Catch and effort (trip) data between 2004 and 2011 from the three landing sites were used to estimate Maximum Sustainable Yield (MSY) using Schaefer & Fox models. The results showed a decreasing trend in the catch rate, from 30.83 tons/trip in 2004 to 12.27 tons/trip in 2011. The estimated MSY is at the range of 34,705- 37,930 tons with optimum efforts for 2,234-2,500 purse seine trips. Thus the level of purse seine fishing effort in 2011, i.e. 3,078 trips, was exceeding the optimum effort. The decreasing trend in the catch rate may indicate overfishing is occurring between 2004 and 2011. For management of the small pelagic fisheries in the waters of Makassar Strait, important action recommended is fishing effort restrictions. The effort allowed would be only in the range of 2,234-2,500 purse seine trips, and the fishing capacity needs to be controled

KARAKTERISTIK BIOLOGI CUMI-CUMI DI PERAIRAN LAUT JAWA

Cumi-cumi merupakan hasil tangkapan sampingan bagi sektor perikanan di Laut Jawa, namun memiliki nilai ekonomi cukup penting. Pengamatan ini bertujuan untuk mengetahui aspek biologi cumi-cumi mencakup komposisi jenis, morfometrik, rasio kelamin dan tingkat kematangan gonad yang tertangkap di perairan utara Jawa di sekitar periaran Rembang, Cirebon dan Belanakan Subang. Ada empat jenis cumi-cumi ditemukan dalam pengamatan ini yaitu Loligo duvauceli sebagai jenis dominan, disusul oleh L. edulis, L. chinensis dan L. singhalensis.  Hubungan panjang mantel dan berat jenis L. duvauceli menunjukkan nilai koefisien pertumbuhan b sebesar 2,003 untuk jantan dan 1,942 untuk betina. Hasil tangkapan individu jantan pada bulan Juni dan Oktober lebih tinggi.  Pengamatan tingkat kematangan gonad menunjukkan bahwa cumi-cumi memijah sepanjang tahun. Karakteristik biologi cumi-cumi di perairan Rembang tidak berbeda nyata dengan cumi-cumi di perairan Cirebon dan Subang, serta memiliki karakteristik yang sama dengan cumi-cumi yang tertangkap di Selat Alas dan perairan India, kecuali waktu puncak pemijahan yang lebih lambat di perairan Rembang dan Cirebon dibandingkan dengan di lokasi lainnya.Squid are not the main target of cath fiesheries in the Java Sea, but it has high economic value. The aim of this observation is to study the biological aspect of squid, such as species composition, morfometric, sex rasio and maturity which were caught in Rembang, Cirebon and Subang. There are four species of squid were recorded during sampling dominated by Loligo duvauceli while the others were L. edulis, L. chinensis and L. singhalensis. The Length-weight relatioship of L.duvauceli showed that the growth coeffiicient were 2,003 and 1,942 for male and female respectively. Male were found common in June and October compare to female. Squid were spawned all over the year. There were no significant differences among squid caught in the waters around Rembang, Cirebon and Subang, and it seems also the same biological characters with squid in Alas Strait Nusa Tenggara Barat (NTB) and Indian waters, but the peak of spawning season in Rembang and Cirebon was late than others

ASPEK BIOLOGI DAN MUSIM PENANGKAPAN LOBSTER (Panulirus spp) DI PERAIRAN KUPANG NUSA TENGGARA TIMUR

Lobster merupakan komoditas perikanan andalan yang banyak dieksploitasi di perairan Kupang untuk memenuhi permintaan pasar dalam dan luar negeri. Hal ini menyebabkan kegiatan penangkapan lobster berlangsung sangat intensif. Penelitian ini bertujuan untuk menganalisis aspek biologi dan musim penangkapan lobster. Data dan informasi yang dikumpulkan meliputi ukuran panjang karapas dan berat serta jenis kelamin tiap-tiap jenis lobster yang tertangkap serta hasil tangkapan dan upaya yang dilakukan secara bulanan. Data tangkapan lobster yang dianalisis dicatat selama periode Oktober 2015 - Desember 2016. Hasil penelitian menunjukkan bahwa  terdapat empat jenis lobster dari kelompok Palinuridae, yaitu lobster bambu (P. versicolor), lobster batu (P. penicillatus), lobster pasir (P. homarus) dan lobster mutiara (Panulirus ornatus). Berdasarkan jumlah individu, tangkapan lobster bambu mendominasi yaitu sekitar 60 % dari tangkapan total. Secara umum ukuran dari semua jenis lobster sesuai dengan ketentuan yang diatur dalam peraturan perundang undangan. Nisbah kelamin yang seimbang dan ukuran rata-rata pertama kali tertangkap lebih besar dari setengah panjang infinitif dan panjang pertama matang gonad menunjukkan bahwa sumber daya lobster masih layak untuk dieksploitasi. Musim penangkapan losbter di wilayah Kupang ini secara umum terjadi pada periode musim penghujan yang mulai dari September sampai Februari. Pembinaan kepada nelayan perlu ditingkatkan agar nelayan tetap patuh pada peraturan perundangan yang berlaku, bahkan dapat diikuti dengan nelayan di wilayah lainnya. Lobster fishery commodity in Kupang. Many lobsters are exploited in these waters to meet domestic and foreign market demand. This led to lobster fishing activities very intensive. The research on lobster resources was conducted to analyze the biology aspect and lobster fishing season. Data included, length of the carapace, individual weight, sex of lobsters and the monthly catches and efforts. The lobster catch data analyzed were recorded during the period of October 2015 - December 2016. The results show that there were four species of lobster from the Palinuridae group,i.e:the ornate spiny lobster (Panulirus ornatus), pronghorn spiny lobster (P. penicillatus), scalloped spiny lobster (P. homarus) and painted spiny lobster (P. versicolor). The catch was dominated by P. versicolor with 60% of the total catch. Generally the size of all lobster species with the regulation concerning the lobster fishing. The balance of sex ratio and the size of Lc of more than 0,5 of Land more than length at first maturity indicates that the lobster resource in Kupang and surrounding waters  is still exploited. The losbter fishing season is generally in the rainy season period from September to february. The increase of guidance to fishermen is needed to keep the fishermen the law and regulations, even can be followed by fishermen in other areas

HUBUNGAN IKAN PELAGIS DENGAN KONSENTRASI KLOROFIL-A DI LAUT JAWA

Klorofil-a banyak ditemukan pada fitoplankton dan menjadi indikator kesuburan perairan. Keberadaan fitoplankton ditandai dengan kandungan klorofil-a yang tinggi dan diikuti oleh keberadaan zooplankton yang akhirnya mempengaruhi keberadaan organisme perairan lainnya seperti ikan pelagis kecil maupun ikan pelagis besar sebagai suatu rantai makanan. Interaksi antara konsentrasi klorofil-a terhadap keberadaan dan konsentrasi ikan pelagis di Laut Jawa belum banyak diketahui. Penelitian ini dimaksudkan untuk mengetahui hubungan interaksi antara klorofil-a terhadap konsentrasi ikan pelagis. Penelitian dilakukan dengan mengumpulkan data runtun waktu hasil tangkapan beberapa jenis pelagis besar dan kecil yang didaratkan di PPI Pekalongan tahun 2007-2011 serta data runtun waktu konsentrasi klorofil-a dari perairan utara Jawa yang diperoleh dari informasi sekunder.Metode analisis korelasi linear sederhana (bivariate correlation) digunakan untukmengetahui ada atau tidaknya pengaruh antar variabel klorofil-a dan konsentrasi ikan pelagis. Hasil penelitian menunjukkan bahwa ikan layang (Decapterus russelli) paling nyata mendapat pengaruh dari konsentrasi klorofil-a (P<0,05) dan berkorelasi positif terhadap konsentrasi klorofil-a dengan nilai koefisien korelasi ( r ) sebesar 0,56, sedangkan ikan pelagis lainnya berkorelasi negatif. Ikan tongkol (Euthynnus affinis) posisinya menempati rantai makanan paling tinggi sebagai pemangsa, mempunyai korelasi positif (r = 0,5) terhadap Rastrelliger kanagurta dan r = 0,56 terhadap Amblygaster sirm.Chlorophyll-a is a light-absorbing pigment that can be found in photosynthetic organisms such as algae and phytoplankton. The evidence of phytoplankton that indicated by high contents of chlorophyll-a may followed the evidence of zooplankton and other micro aquatic organism as a food chain component. An overview of interrelationships between chlorophyll-a and pelagic fishes in the waters around Java Sea have not much investigated. The research was attempted to study the interaction between chlorophyll-a abundance and the abundance of small and large pelagic as well as relationship among small and large pelagic as prey-predators component. Research conducted by collecting time series catch data of small and large pelagic species landed at PPI Pekalongan during the period of 2006-2012, as well as the data of chlorophyll-a abundance through previous research studies. The results showed that layang (Decapterus russelli) was the most significant species that positively correlated to abundance of chlorophyll-a (P < 0.05) with value of r = 0.6. while others pelagic species have negative correlation. As a predator species, tongkol (Euthynnus affinis) was positively correlated ( r = 0.5) to the abundance of banyar (Rastrelliger kanagurta) as well as juwi (Amblygaster sirm) with r value 0.56

PENGARUH LAMA SETTING DAN JUMLAH PANCING TERHADAP HASIL TANGKAPAN RAWAI TUNA DI LAUT BANDA

Rawai tuna atau tuna longline merupakan salah satu alat tangkap yang sangat efektif untuk menangkap tuna dan merupakan alat tangkap yang selektif. Kegiatan observasi di atas kapal telah dilakukan selama Oktober 2002 – Februari 2003 pada 31 kapal dan pada Oktober-November 2011 pada 1 kapal yang beroperasi di Laut Banda. Data yang dicatat selama observasi berupa data trip kapal, setting, waktu setting (mulai dan selesai), jumlah pancing yang digunakan tiap setting dan hasil tangkapan berdasarkan jenis ikan. Tujuan dari penelitian ini adalah untuk mengetahui perbedaan lama setting dan jumlah pancing terhadap hasil tangkapan rawai tuna di perairan Laut Banda. Waktu setting selama penelitian berkisar antara 190-345 menit sedangkan untuk pancing berkisar antara 660-1600 pancing. Data waktu untuk setting kemudian dibedakan dalam enam kelompok dan untuk jumlah pancing dibedakan dalam empat kelompok. Hasil pengelompokan data ini kemudian dilakukan analisis ragam atau analysis of variance (ANOVA). Analisis digunakan untuk mengetahui pengaruh perbedaan antar kelompok. Hasil penelitian menunjukkan bahwa lama setting tidak berpengaruh nyata terhadap hook rate rawai tuna sehingga tidak berpengaruh juga terhadap hasil tangkapan. Sedangkan perbedaan jumlah pancing berpengaruh nyata terhadap nilai hook rate rawai tuna di Laut Banda. Jumlah pancing dengan nilai hook rate tinggi dan hasil tangkapan paling banyak adalah pada jumlah pancing 1201-1600 buah dengan didominasi ikan tuna mata besar. Tuna longline is an effective fishing gear to catch tuna. It is also a selective  fishing gear. Observation on the board had been conducted during October 2002 - February 2003 which 31 tuna longline vessels and October-November 2011 only 1 vessel. These vessels operated in the Banda Sea. Data of boat trips, setting, time setting (start and finish), the number of hooks used for each setting and catch were collected. The purpose of this paper is to determine differences in the setting time and the number of hooks for tuna longline catches. Range of the setting time for the study between 190-345 minutes and then divided into 6 groups. Range of hooks between 660-1600 hooks and then divided into 4 groups. Analysis of variance (ANOVA) performed to determine the effect of differences between groups. The results showed that the length of setting did not significantly affect hook rate while differences in the number of hooks are significantly affects the hook rate. The highest tuna longline hook rate and the most of the tuna longline catch on 1201-1600 hooks with begeye tuna dominated

NISBAH KELAMIN, UKURAN PERTAMA KALI TERTANGKAP DAN CATCH PER-UNIT EFFORT DUA JENIS LOBSTER KIPAS (SCYLLARIDAE) DI PERAIRAN KUPANG DAN SEKITARNYA

Pemanfaatan lobster kipas (Scyllaridae) yang tertangkap di Perairan Kupang terus meningkat, tetapi informasi mengenai kondisi stok dan aspek biologi nya belum banyak diketahui. Tulisan ini mengkaji nisbah kelamin, rata-rata ukuran pertama kali tertangkap dan catch per-unit of effort (CPUE) lobster kipas di perairan Kupang dan sekitarnya. Kedua spesies lobster kipas yang dianalisis merupakan hasil tangkapan sampingan jaring krendet yang dilakukan oleh nelayan setempat. Jenis data yang dianalisis meliputi data penangkapan dan biologi lobster yang dikumpulkan selama periode Oktober 2015 - Desember 2016. Hasil penelitian menunjukkan bahwa terdapat dua jenis lobster kipas hasil tangkapan sampingan di perairan Kupang, yaitu Scyllarides haanii dan Thenus indicus dengan komposisi hasil tangkapan T. indicus lebih banyak dari S. haanii. Rata-rata ukuran panjang pertama kali tertangkap (Lc) untuk lobster T. indicus betina berdasarkan panjang karapas adalah sekitar 93,79 dan 94,18 mm untuk jantan, sedangkan untuk lobster S. haanii betina adalah 101,40 mm dan 104,06 mm untuk jantan. Nisbah kelamin dari kedua jenis lobster ini masih dalam kondisi seimbang. Rata-rata nilai CPUE lobster jenis T. indicus 3,7 kg/trip lebih besar dibandingkan dengan nilai CPUE S. haanii sebesar 0,8 kg/trip. Nilai CPUE dari tiap-tiap lokasi penangkapan tidak berbeda nyata antar lokasi penangkapan.The utilization of slipper lobster (Scyllaridae) caught in around Kupang waters is increased continuously, however a little information on its stock and biological aspect is available. This paper describes sex ratio, length at first capture and the catch per-unit of effort (CPUE) of the slipper lobster population in the Kupang and surrounding waters. Both slpper lobsters analyzed are a by-catch of a gillnet operated by local fishermen. The data analysized included cacth and biology of lobster collected during the period of October 2015 to December 2016. Results show that there were two types of slipper lobster as by-catch in Kupang waters, namely Scyllarides haanii and Thenus indicus with the number of T. indicus higher than S. haanii. The first lengths of captured (Lc) for female T. indicus based on carapac lenght was 93.79 and 94.18 mm for male, while female S. haanii were 101.40 mm (female) and 104.06 mm for male. The sex ratio of both types of lobsters was still in a balanced condition. The average CPUE of T. indicus was 3.7 kg/trip, higher than that CPUE value of S. haanii of only 0.8 kg/trip. The CPUE value was significantly no different between the fishing location

ESTIMASI STATUS STOK SUMBER DAYA KEPITING BAKAU (Scylla serrata) DI ESTUARI MAHAKAM, KALIMANTAN TIMUR

Produksi nasional kepiting bakau yang terus menurun serta semakin sulitnya nelayan menangkap kepiting bakau di habitat aslinya, menjadi indikator terjadinya ancaman keberlanjutan sumberdaya di alam. Kepiting bakau (Scylla serrata) merupakan salah satu komoditas perikanan penting propinsi Kalimantan Timur, yang sebagian besar berasal dari hasil tangkapan nelayan di sekitar perairan Delta Mahakam. Informasi status stok kepiting bakau di Estuari Mahakam belum tersedia sehingga menjadi kendala dalam menyusun kebijakan pengelolaan sumberdaya kepiting bakau pada skala daerah dan nasional. Penelitian ini dimaksudkan untuk mengetahui status stok kepiting bakau di Estuari Mahakam dengan menggunakan metode rasio potensi pemijahan induk berbasis data panjang (Length-Based Spawning Potential ratio/SPR), dalam kurun waktu 5 bulan, yaitu November 2016-Maret 2017. Hasil analisis menunjukkan bahwa nilai SPR saat ini (actual estimate) diperoleh sebesar 0,43 atau sebesar 43% sehingga dikategorikan sebagai fully-moderate exploited karena masih berada di atas ambang batas yang telah ditetapkan sebesar 30%. Nilai SPR 43% mengindikasikan bahwa masih terdapat biomassa kepiting bakau dewasa sebesar 43% di alam, untuk menunjang keberlanjutan rekruitmen. Di samping itu, laju penangkapan (F) terhadap mortalitas alami (M) yang mencapai 0,86 menunjukan bahwa kematian alami lebih mendominasi dibandingkan tekanan penangkapan.The decreasing in national production of mangrove crab and the difficulties for fishermen to catch mangrove crab in its natural habitat, become an indicator of the threatened of those resources in nature. Mangrove Crab (Scylla serrata) is one of the important fishery commodities of East Kalimantan province, mostly caught around the waters of Mahakam Estuary. Meanwhile, information concerning the stock status of mangrove crab in Mahakam Estuary is not yet available so it becomes an obstacle in formulating policies related to the management of mangrove crab resources at the regional and national scale. This research is intended to know the stock status of mangrove crab (Scylla serrata) in Mahakam Estuary by using Length-Based Spawning Potential ratio (SPR). The result of analysis show that the value of the current SPR (actual estimate) is 0,43 or 43%, it is categorized as fully-moderate exploited because it is still above the predefined threshold of 30%. The SPR value indicates about 43% of mature crabs biomass are still available to support the sustainability of recruitment. Nevertheless, the rate of capture (F) on natural mortality (M) has reached 0,86 which is mean that fishing exploitation has contributed 86% to the mortality of mangrove crab in its habitat

PENINGKATAN KINERJA PELABUHAN PERIKANAN: STUDI KASUS PELABUHAN PERIKANAN NUSANTARA BRONDONG

Pengukuran waktu penyerahan ikan dan tingkat aktifitas dermaga, sebagai bagian dari usaha peningkatan kinerja di PPN Brondong, dilakukan dengan menggunakan simulasi antrian. Simulasi dilakukan dengan memanfaatkan data kedatangan dan hasil tangkapan kapal, data enumerator dan sampling di PPN Brondong periode Agustus-Desember 2012-Januari-Juli 2013. Hasil penelitian menunjukkan bahwa peningkatan kinerja dapat dilakukan melalui kesepakatan semua pihak yang berkepentingan untuk mengubah jam pelayanan armada dogol mingguan dan rawai dasar dari jam 05:00 menjadi jam 02:30 serta memindahkan kegiatan sortasi ikan dari dermaga ke Pusat Pendaratan dan Distribusi Ikan (PPDI). Langkah tersebut dapat menurunkan tingkat aktifitas dermaga pada musim ikan menjadi lebih ideal, 76-79%; menambah 29 unit kapal setara dogol mingguan per hari untuk sandar serta meningkatkan efektifitas tenaga kerja sortasi dan akan mempersingkat waktu penyerahan ikan sebesar 52%.The measurements of fish delivery time and berth occupancy ratio, as part of the efforts to improve the performance of Brondong Achipelagic Fishing Port, were done using quenching simulation. The data on number vessel arrival and their catches of August to December 2012-January-July 2013 and enumerator’s data as well as sampling data were used in the simulations. Results showed that the port performance improvement can be done through agreement of all parties concerned to change the start of port service for weekly Danish seiners and bottom long liner from 05:00 am to 02:30 am and to move on sorting activity from the pier to the fish landing and distribution centre (PPDI). Such actions would reduce the level of berth activity, during fishing season, to more ideal value of 76-79%; augment additional 29 units of weekly Danish seines per day to berth and increase the effectiveness of labor sorting. Finally, these measures would shorten fish delivery time by 52%