INTER-SPECIFIC COMPETITION AND FISHING EFFECT TO POPULATION DYNAMIC OF BALI SARDINE (SARDINELLA LEMURU)

Stock-recruitment relationship of Bali sardine was investigated based on Beverton-Holt model by assuming inter-specific competition. Model is modified to incorporate the effect of fishing pressure that is density-independent to population dynamic by developing scenario fishing on adult and/or juvenile population. The results show that harvested adult the dramatic decline of recruitment supply. However, harvested juvenile is led to the positive response to population size, as an increase in fishing mortality rate will reduce competition mortality rate. Precautionary approach required by considering bipartite life cycle.

INDIKATOR KELIMPAHAN SUMBERDAYA IKAN SIRO (AMBLYGASTER SIRM) DI LAUT JAWA

Pemanfaatan ikan siro (Amblygaster sirm) di Laut Jawa menunjukkan gejala overfishing. Beberapa aksi pengelolaan telah dilakukan untuk mengatasinya dan efektifitasnya dipertanyakan. Penelitian ini bertujuan untuk memperbaharui status populasi ikan siro di Laut Jawa dengan menggunakan beberapa indikator, yakni kelimpahan dan biologi. Pengumpulan data dilakukan di Pelabuhan Perikanan Nusantara (PPN) Pekalongan selama 6 bulan (Oktober 2013 - Maret 2014). TropFishR package digunakan untuk menganalisis beberapa parameter pada 830 individu. Hasil penelitian menunjukkan ukuran panjang berkisar antara 14,1-24.5 cmFL. Parameter pertumbuhan ikan siro (Linf, K dan t0) masing-masing sebesar 21.9 cmFL, 1,7/tahun dan 0,45. Perbandingan antara jumlah kelamin jantan dan  betina dalam kondisi seimbang. Pola pertumbuhan ikan siro bersifat alometrik negatif (2,259), dimana pertumbuhan panjang lebih cepat dari pertumbuhan beratnya. Ukuran panjang pertama kali matang gonad (Lm) dan ukuran panjang pertama kali tertangkap (Lc) masing-masing sebesar 16,8 cmFL dan 15,4 cmFL. Indikator kelimpahan menunjukkan kecenderungan penurunan. Selain itu, Lc lebih kecil dari Lm yang mengindikasikan terjadinya growth overfishing

STUDI DAYA DUKUNG SUMBER DAYA IKAN DI WADUK JATIBARANG SEMARANG

Waduk Jatibarang merupakan waduk yang belum lama beroperasi dan masih tergolong waduk baru. Kegiatan perikanan yang berkembang didominasi oleh perikanan pancing. Selain penangkapan, peningkatan produksi juga dilakukan dengan penebaran ikan, namun belum didukung kajian daya dukung yang memadai. Penelitian ini dilakukan untuk mengetahui nilai daya dukung sumber daya ikan di waduk Jatibarang. Kegiatan penelitian dilakukan pada Bulan Mei dan Juli 2018 yang meliputi 4 (empat stasiun yang mewakili inlet, tengah dan outlet waduk. Data primer yang dikumpulkan meliputi kualitas air (parameter fisika, kimia dan biologi). Data pendukung penelitian meliputi elevasi muka air, diperoleh dari Balai Besar Wilayah Sungai Pemali-Juana, dan data kedalaman, diperoleh dari akuisisi data GPS Sounder. Hasil penelitian menunjukkan bahwa nilai daya dukung sumber daya ikan di Waduk Jatibarang berkisar antara 3,57-6,3 ton/tahun. Kedalaman perairan sangat mempengaruhi nilai daya dukung. Nilai daya dukung lebih rendah pada kedalaman perairan lebih dari 20 m dan relatif tinggi pada kedalaman lebih dari 10 m. Selain pengaruh kedalaman juga terdapat pengaruh lain seperti fluktuasi muka air, kelimpahan plankton, kecerahan, dan unsur hara berupa nitrat. Diharapkan kajian terkait potensi produksi dapat dilakukan untuk optimalisasi pemanfaatan perikanan yang berkelanjutan.Jatibarang Reservoir is a new operating reservoir. Existing fishing activities are dominated by handline. Except fishing activities, many fish have been stocked to improve the production, but it has not been supported by adequate carrying capacity studies. The purpose of this research was to determine the value of carrying capacity of fish resources in the Jatibarang Reservoir. The study was conducted in May and July 2018 representing the inlet, center, and outlet of the reservoir. The collected data consisted of physical, chemical, and biological data obtained at 4 (four) research stations representing the inlet, center, and outlet of the reservoir. Supporting data include water level elevation obtained from the Pemali-Juana River Basin Authority and bathymetry data obtained from GPS Sounder data acquisition. The results showed that the value of carrying capacity of fish resources in the Jatibarang Reservoir is 3.57-6.3 tons/year. The depth of the waters greatly affects the value of carrying capacity. The value of smaller carrying capacity occurs at the water depths of more than 20 m, but is relatively high at the depths of more than 10 m. There are also other influences such as water level fluctuations, plankton abundance, water brightness, and nitrates. Furthermore, a study of production potential should be carried out to optimize the sustainable fisheries utilization

COST-EFFECTIVE APPROACH TO ESTIMATE UNREPORTED DATA: REBUILDING HISTORY OF LIFT-NET FISHING IN KWANDANG WATERS

This paper aims to develop cost-effective approach regarding the estimation unreported annual catch data of lift-net fishery using Google Earth imagery. Lift net fishery is one of the main fishing activities of coastal community in Kwandang Bay, it has been faced problem of uncertain fisheries status due to limited recorded data. Combination of a Monte Carlo procedure was applied by involving couple of assumptions on parameters such as estimate growth rate of the total number of lift-net per years (10%), day at sea per unit per month (21 days) and operated lift-net per month (50% and 80%). The results showed that 101 units of lift-nets were found around Kwandang waters based on Google Earth imagery recorded in October, 7th 2010, and this were used as a benchmark of calculation. This prediction was 28 units higher than official data from North Gorontalo District of Marine Affairs and Fisheries Services (DKP Gorontalo Utara). Compared with capture fisheries statistics issued by Kwandang CFP, the estimated lift-net catches based on two-scenarios represent additional catches of 46 % and 86 %. These results suggested and could be used as a correction index to improve the reliability of Kwandang District officially reported fisheries statistics as a baseline to develop a local common fisheries policy

“PANGLIMA DANAU” SEBAGAI MODEL PENGELOLAAN SUMBERDAYA PERIKANAN BERKELANJUTAN BERBASIS KEARIFAN LOKAL DI DANAU ANEUK LAOT

Perikanan di perairan daratan bersifat open access di mana setiap orang atau kelompok nelayan memanfaatkan sumberdaya ikan untuk memaksimalkan manfaat ekonomi, namun mengabaikan manfaat ekologi dan sosial. Pemanfaatan perikanan yang demikian dapat memperburuk stok sumberdaya ikan, menjadi tidak berkelanjutan dalam jangka panjang. Pemanfaatan perikanan di Danau Aneuk Laot bersifat rentan sehingga diperlukan model pengelolaan perikanan yang tepat. Kearifan lokal seperti “Panglima Danau” merupakan salah satu model pengelolaan perikanan berbasis komunitas yang dapat digunakan untuk mengatur upaya penangkapan ikan di Danau Aneuk Laot. Penulisan ini bertujuan untuk mengetahui peran Panglima Danau sebagai instrumen pengelolaan sumberdaya perikanan perairan daratan berbasis kearifan lokal di Danau Aneuk Laot Kota Sabang. Berdasarkan hasil wawancara dan literature review, kearifan lokal “Panglima Danau” yang berbasis komunitas menunjukkan performa yang baik menjaga keberlanjutan sumberdaya ikan nila di Danau Aneuk Laot dan mampu meningkatkan pendapatan nelayan lokal. Danau Aneuk Laot memiliki keanekaragaman jenis ikan yang rendah, dan didominasi spesies introduksi. Potensi tangkapan diperkirakan 315 kg/ha/tahun, dengan potensi hasil tangkapan maksimum lestari 33.49 ton/tahun. Upaya pemulihan stok ikan di Aneuk Laot dilakukan oleh nelayan dan pemerintah melalui kegiatan restocking secara regular. Kearifan lokal “Panglima Danau” dinilai berhasil karena dilengkapi dengan aturan pengelolaan yang cukup jelas dalam hal kapan dan bagaimana cara yang baik menangkap ikan, serta adanya denda yang diberikan kepada nelayan yang melanggar kesepakatan bersama. The inland fishery generally practices open access where an individual or a fisher group may extract the resources to maximize the economic rent but disobeying the ecological and social benefits. Extracting the Nile tilapia resources that exceed its Maximum Sustainable Yield may increase the fishers’ income in the short run, but it could also exacerbate those resources; end up in unsustainable stock in the long run. Since Aneuk Laot fishery is vulnerable, its management approach should consider a proper management model. The local wisdom “Panglima Danau” is a well-known local management approach that regulates fishing efforts with community right-based model. This research evaluates the role of the “Panglima Danau” local wisdom by collecting the related information through questionnaires interviews and reviewing the related previous studies and research projects. The results show that Panglima Danau performs well in maintaining the fish stock sustainability while leveraging the local income. We found that Aneuk Laot Lake has low fish species diversity, but abundance in introduced fishes. The potential catch is about 315 kg/ha/year, with a sustainable catch potential is about 33.49 tons/year. The government and fishers restored the fish stock in Lake Aneuk Laot by conducting regular fish stocking. It is concluded that this local wisdom seems to be useful since it is community-based fishery management approached, equipped with clear guidance on when and how to fish and the penalties that might be imposed on the fishers who break the responsibility.

CULTURE BASED FISHERIES (CBF) SEBAGAI UPAYA MENINGKATKAN PRODUKSI IKAN DI WADUK

Sistem pangan global semakin dituntut untuk memenuhi permintaan ikan seiring meningkatnya tingkat konsumsi ikan di masa depan. Tujuan penulisan makalah ini adalah untuk memberikan gambaran bahwa CBF sebagai solusi cepat dalam meningkatkan produksi ikan termasuk mengoptimalkan produktivitas di suatu perairan sehingga mempersempit kesenjangan antara permintaan akan sumber protein hewani dan pasokan sumberdaya ikan melalui peningkatan produksi. Melalui analisis deskriptif terhadap data statistik perikanan nasional tahun 2002-2017, kajian pustaka terkait dengan CBF dan hasil tangkapan yang didaratkan di Waduk Malahayu tahun 2008-2016, diperoleh gambaran bahwa upaya meningkatkan produksi ikan melalui CBF di Indonesia dengan mengikuti kaidah ilmiah merupakan opsi yang tepat untuk meningkatkan produksi perikanan tangkap. Penerapan CBF memerlukan penguatan kelembagaan, petunjuk teknis yang jelas dan tersosialisasi dengan baik serta penguatan peran lembaga penyedia benih. The global food system is increasingly being demanded to meet demand as the level of fish consumption increases in the future. The purpose of this paper is to provide an overview of CBF as a solution in narrowing the gap between the demand for sources of animal protein and the supply of fish resources through increased the production include maximizing the productivity. Through descriptive analysis of the national fisheries statistical data for 2002-2017, literature review related to CBF and catches landed in Malahayu reservoir in 2008-2016, an illustration is that efforts to increase fish production through CBF in Indonesia by following scientific rules are the right option to increase capture fisheries production respectively. Implementation of CBF requires institutional strengthening, clear technical guidance and well-socialized and strengthening the role of seed provider institutions

FISHERIES SANCTUARY PLANNING IN PRACTICE: LESSON LEARNT FROM ECOSYSTEM APPROACH TO FISHERIES MANAGEMENT IN NORTH KALIMANTAN PROVINCE

Governor Decree of North Kalimantan No. 26 in 2014 concerning Management of Bombay Duck in the North Kalimantan Province Waters was established in order to address over-exploitation of bombay duck (Harpadon nehereus) population. Fisheries sanctuary is the feasible solution that was agreed by comprehensive stakeholder discussion. This research aims to extract and elaborate our experiences on establishing fisheries sanctuary in the Bangkudulis waters which focus on science communication and in the fisheries sanctuary planning. The acoustic and larva survey conducted to support the consensus and to proof the traditional ecological knowledge of the communities. The results showed that the proposed conservation area of the Bangkudulis waters has significant ecological function to ensure the sustainability of bombay duck population. The distribution and abundance of larva and juveniles were found higher in that area. The approach and challenges to deal with ecological and socio-economic aspects as well as recommendations were discussed in this paper

THE DISTRIBUTION AND ABUNDANCE OF DECAPOD AND FISH COMMUNITIES IN CLEVELAND BAY, AUSTRALIA

Spatial and temporal variations in the fish and decapod communities were investigated at three stations in Cleveland Bay along with other zooplankton and phytoplankton communities. The linkage between biological assemblages and physical properties of the ocean was explained to develop better understanding of population dynamic of planktonic communities. Biological and physical properties data were gathered in 3 stations by 6 different trips. The results show that there is a significant association between daytime and tidal period to the abundance of planktonic communities (P < 0.05). Spatial distribution of fish and decapod communities are likely explained by “predator pit” and “match/mismatch” concepts to increase the survival probability along with physical properties of the ocean

KEPADATAN STOK, KOMPOSISI JENIS IKAN DEMERSAL DAN UDANG DI SELAT TIWORO, SULAWESI TENGGARA

Penelitian ini dilakukan dengan kapal pukat tarik di Selat Tiworo, pada bulan Desember 2015. Kapal yang digunakan berukuran 10 GT yang berbasis di Pangkalan Pendaratan Ikan, Bombana. Estimasi kepadatan stok dilakukan dengan menggunakan metode sapuan dengan pengambilan contoh acak bertingkat. Hasil penelitian diperoleh rata-rata laju tangkap ikan demersal 46,171 kg/jam dengan  kepadatan stok rata-rata sebesar 3,6 ton/km2, sedangkan udang 1,537 kg/jam dengan kepadatan stok 0,18 ton/km2. Kepadatan stok ikan demersal tertinggi 4.588,55 kg/km2 terdapat pada strata kedalaman 30-40 m dan terendah 2.925 kg/km2 pada strata kedalaman 20-30 m. Komoditas udang diperoleh kepadatan stok udang tertinggi pada kedalaman 10-20 m (380,91 kg/km2) dan terendah 1,85 kg/km2 pada kedalaman 30-40 m. Komposisi 10 (sepuluh) besar hasil tangkapan didominasi family Leiognathidae 17,78%, Nemipteridae 8,66 %, Serranidae 6,87%, Myxinidae 6,33%, Trichiuridae 5,66%, Psettodidae 5,21%, Tetraodontidae 4,54%, Scianidae 4,13% dan Apogonidae 3,77%. Sumberdaya udang didominasi dari jenis Trachipenaeus asver 35,59%, Metapenaeus ensis 22,73%, Penaeus semisulcatus 13,43%, Penaaeus longistilus 12,47%, Penaeus merguensis 4,27%, Penaeus monodon 1,71%, dan Penaeus indicus 0,07%

PARAMETER POPULASI DAN TINGKAT PEMANFAATAN IKAN KUNIRAN (Upeneus sulphureus, Cuvier 1829) DI PERAIRAN SELAT MALAKA

Sumberdaya ikan kuniran (Upeneus sulphureus) di Selat Malaka telah dieksploitasi sejak lama dengan alat tangkap pukat tarik, terutama sebelum adanya moratorium pelarangan alat tangkap trawl dan sejenisnya. Penelitian dilaksanakan pada bulan Januari - November 2014 di Perairan Selat Malaka. Pengukuran panjang cagak ikan kuniran diambil secara acak terhadap 2.694 sampel yang dilakukan di PPS Belawan. Tujuan penelitian ini adalah untuk menganalisis beberapa parameter pertumbuhan populasi ikan kuniran (Upeneus sulphureus) di Selat Malaka. Analisis data parameter populasi dianalisis menggunakan FAO-ICLARM Stock Assessement Tools (FISAT). Hasil analisis diperoleh beberapa parameter populasi ikan kuniran dengan koefisien pertumbuhan (K) sebesar 0,80 per tahun, (L∞) 21,0 cm, (M) 1,73 per tahun (F) 2,51 per tahun, dan E 0,59 per tahun. Penambahan baru individu ke dalam populasi berlangsung sepanjang tahun dan mencapai puncaknya terjadi pada akhir musim timur (Juni – Agustus) sampai musim peralihan II (September – Nopember). Pemanfaatan ikan kuniran di perairan Selat Malaka sebelum moratorium pelarangan pukat tarik dalam kondisi jenuh (Fully exploited)