<p>Masuknya jenis ikan asing berpotensi merubah keseimbangan pada perairan umum daratan, dan di Indonesia gejala ini sudah mulai terlihat. Makalah ini bertujuan untuk membahas lebih lanjut tentang perkembangan introduksi ikan asing, strategi pelaksanaan intoduksi dan berbagai dampaknya terhadap komunitas ikan asli perairan di Indonesia. Penelitian dilakukan melalui penelusuran dan studi pustaka tentang: sejarah kegiatan introduksi ikan yang dilakukan ke Indonesia, jenis-ikan introduksi ikan di Indonesia dan kegiatan introduksi ikan yang telah dan dilakukan di Indonesia beserta dampaknya. Verifikasi lapangan dilakukan pada tahun 2011 di beberapa danau dan waduk antara lain Danau Sentani, Danau Kerinci, Danau Matano dan Waduk Riam Kanan. Data yang terkumpul ditabulasi dan dianalisis secara deskriptif. Hasil penelitian menunjukkan bahwa introduksi ikan asing dilakukan di Indonesia sebelum tahun 1900. Introduksi ikan yang telah dilakukan selama ini, lebih banyak dilakukan tanpa melalui kajian ilmiah yang mendalam dan telah terbukti mengakibatkan hilang atau berkurangnya populasi ikan asli atau endemik serta menjadi agen pembawa penyakit.</p><p>The entry of alien fish species could potentially change the balance of the inland waters and in Indonesia this symptoms was shown. The paper aims are to discuss more about the development introduction of alien fish species, the introduction implementation strategy and its impact to indigenous fish species communities in Indonesian inland waters. The study was conducted through a literature research about: the history of fish introductions activities which carried out in Indonesia, the species of fish introduction in Indonesia and the activities of introduction fish that have been conducted in Indonesia and its impact. Field verification was conducted in 2011 at several lakes and reservoir such us: Sentani Lake, Kerinci Lake, Matano Lake and Riam Kanan Reservoir. The collected data were tabulated and analyzed descriptively. The results showed that alien fish introductions were conducted in Indonesia before 1900. Introductions of fish those have been conducted so far is mostly done without in-depth scientific study and it has been shown affected in lost or reduced populations of indigenous or endemic species of fish as well as being an agent of disease carrier.</p>

In relation to the achievement of the target SDG’s No. 14, the sustainable shark fisheries management need to implement. As a part of the tuna fisheries by-catch, a high number of shark resources have been caught in the Indian Ocean waters. One of the main vessels of tuna catchers in the Southern Indian Ocean of Java is the tuna longline from Cilacap. This paper aims to analyze the shark by-catch of tuna longline in the Indian Ocean in the south Java that landed in Cilacap. The research data was obtained from daily recording activities of fishing vessel loading activities by Cilacap Ocean Fisheries Port staff during the period of 2013-2017. The analysis was done through data tabulation, graphical approaches, and data trend analysis through the availability of time series data. The data analyzed include fleet development, fishing ground, catch composition and CPUE value. The results of the analysis show that there are about eight species of sharks that are by-catch of tuna longline from Cilacap. The highest shark by-catch occurred in April with CPUE averaging 9 kg/day/vessel. The blue shark (Prionace glauca) is the dominant shark catch which reaches 66% of the total sharks catch.

Degradasi kualitas perairan di danau dan waduk semakin meningkat menyebabkan terjadinya kasus kematian ikan secara massal. Untuk itu dilakukan kajian yang bertujuan untuk merumuskan upaya pencegahan dan penanganan kematian massal ikan di danau dan waduk, terutama bagi ikan-ikan budidaya, melalui telaah dan analisis berbagai literatur. Hasil kajian menunjukkan bahwa kasus kematian massal ikan dapat disebabkan oleh berbagai faktor, diantaranya: i) perairan kekurangan oksigen; ii) ikan mengalami keracunan akibat gas-gas beracun; iii) serangan penyakit pada ikan; iv) kelebihan daya dukung perairan; v) perubahan suhu perairan; serta vi) lokasi keramba jaring apung (KJA) berada di perairan waduk yang dangkal. Untuk meminimalkan kasus kematian massal ikan, upaya pencegahannya antara lain: (a) memahami penyebab kematian ikan; (b) fokus pada pencegahan; (c) perhatikan sanitasi ikan yang dibudidayakan; (d) pengecekan rutin kesehatan ikan; (e) memahami jenis parasit/pathogen, dan perlunya diagnosa dan perlakukan terhadap penyakit ikan yang diketahui; (f) pengurangan kepadatan ikan budidaya; (g) pemberian pakan ikan tidak berlebihan untuk meminimalkan buangan limbah organik ke perairan; (h) pemasangan sistem aerasi darurat; dan (i) pemindahan unit KJA ke perairan yang lebih dalam. Langkah-langkah penanganan jika terjadi kematian massal ikan diuraikan dalam tulisan ini. Diperlukan kolaborasi diantara pemangku kepentingan dalam upaya penanganan kematian ikan untuk mencegah terjadinya dampak yang lebih buruk pada ikan yang belum mengalami kematian massal.Water quality degradation which caused mass fish mortality has increased in lakes and reservoirs. This study aimed to provide information on efforts of prevention and to handle the fish mass mortality through reviewing and analyzing various literatures. Results showed that the mass mortality of fish was caused by several factors, including: i) oxygen-deficient waters; ii) fish poisoning due to toxic gases; iii) disease attack on fish; iv) excess waters carrying capacity; v) water temperature changes; and vi) the location of floating net cages (KJA) in shallow waters reservoir. To minimize the fish mass mortality, preventive measures that can be taken include: (a) understanding the causes of fish mass mortality; (b) focus on prevention; (c) paying attention on sanitation of cultivated fish; (d) routine checks on the fish health; (e) understanding the types of parasites or pathogens and the need for diagnosis and treatment of the typed fish diseases; (f) reduction in the abundance of cultivated fish; (g) reduction in fish feeding for minimizingorganic waste disposal; (h) installation of emergency aeration systems; and (i) transferring the cages net to other deeper water areas. Furthermore, handling efforts in the event of a mass mortality occurrence of fish are described in this paper. Collaboration and coordination among stakeholders are needed in efforts to deal with the mass mortality of fish in lakes and reservoirs, to prevent a worse impact for fish which are still alive in cages net.

<p>Sungai Serkap memiliki sumberdaya ikan yang unik dan beragam. Jumlah jenis ikan di Sungai Serkap pada tahun 2013 ditemukan sebanyak 54 jenis yang sebagian besar merupakan ikan perairan asam. Selain memiliki sumberdaya ikan yang melimpah, Sungai Serkap merupakan habitat ikan merah (<em>Pectenocypris</em> sp), ikan arwana kuning (<em>Scleropages aureus</em>) dan labi-labi (<em>Amyda cartilagynea</em>), dimana arwana kuning dan labi-labi termasuk biota yang dilindungi sedangkan ikan merah diduga ikan endemik dan merupakan spesies baru dari genus Pectenocypris. Walaupun ekosistem perairan Sungai Serkap masih alami namun aktifitas manusia disekitarnya dapat mengancam kualitas lingkungan dan kelestarian sumberdaya ikan di sungai tersebut. Beberapa faktor yang dapat mengancam kelestarian sumberdaya ikan antara lain: i) pembalakan liar, ii) kebakaran hutan, iii) penutupan kanal atau anak-anak sungai, iv) penangkapan pada musim pemijahan, v) eksploitasi jenis ikan tertentu dan vi) belum adanya reservat atau suaka perikanan. Untuk menjamin keberlanjutan sumberdaya perikanan di masa mendatang diperlukan langkah-langkah pengelolaan sebagai berikut: (1) penetapan suaka perikanan, (2) rehabilitasi hutan rawa, (3) penetapan waktu dan lokasi penangkapan ikan, (4) re-stocking ikan arwana kuning dan (5) pengembangan co-managemen.</p><p> </p><p>Serkap river has been unique and diverse of fish resources. In 2013, the number of fish that found in Serkap River were 54 species which mostly are acidic water fish. Besides of having abundant resources, the Serkap River is a habitat for red fish (<em>Pectenocypris</em> sp), arwana yellow fish (<em>Scleropages aureus</em>) and labilabi (<em>Amyda cartilagynea</em>), where arwan yellow fish and labi-labi including protected biota while the red fish suspected as an endemic fish and represent a new species from Pectenocypris genus. Although the ecosystems in Serkap River is still natural/clean/unspoiled but human activity around there could threaten the environmental quality and preservation of fish resources in the river. Some factors that could threaten the sustainability of fish resources are: i) illegal logging, ii) forest fire, iii) the closure of canals or creeks, iv) fishing on spawning season, v) exploitation of certain fish and vi) the absence of reservat or fish santuary. Special treatment of fisheries management is needed to ensure the sustainability of fisheries resources in the future as follows: (1) the determination of fish santuary, (2) the rehabilitation of swamp forest, (3) determination of time and location of fishing, (4) restocking of arwana yellow fish and (5) development of comanagement.</p>

Komodo National Park (KNP) is administratively located in the Komodo district, West Manggarai Regency, East Nusa Tenggara Province. The geographical position is connected to the coast of the Flores Sea and the Indian Ocean. Fishing is the main livelihood for approximately 13% of the district population. There are 60 reef fish species found in the area, and small scale fishers were mostly operated to support their livelihood. This study aims to determine the vulnerability of five high-value reef fish species to environmental exposure, i.e., Plectropomus leopardus (Lacepède, 1802); Variola louti (Forsskål, 1775); Epinephelus fuscogutattus (Forsskål, 1775); Lutjanus malabaricus (Bloch & Schneider, 1801); and Lutjanus gibbus (Forsskål, 1775). The observation was carried out during 2019. The analysis was performed by the method for assessing the vulnerability of marine fish and shellfish species to a changing climate. The approach consisted of sensitivity attribute and exposure factor based on reasonable time series data availability. The results indicated that the vulnerability indices of P. leopardus, V. louti, and E. fuscoguttatus to aquatic environment variabilities were high. This means that the three populations are strongly influenced by environmental conditions on the coral reef ecosystem. The vulnerability indices of L. malabaricus and L. gibbus to the aquatic environment variables were moderate or sufficiently affected by environmental conditions to the coral reef ecosystem. One should be considered that these findings with the data-quality scoring at a category 2 and 3 or limited data to adequate data. These indices showed that necessary to manage and protect the marine and coastal ecosystems of Komodo National Park and its surroundings from anthropogenic pressures and adapt to environmental exposure factors. This should be supported by the identification of grouper and snapper spawning aggregation areas in the National Park.