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Struktur trofik dan biologi populasi ikan di Perairan Pulau Semak Daun Kepulauan Seribu
No full textReef fishes is one of primary reef resource exploited by artisanal fishers in most Indonesian coastal areas and small islands. Sustainable management of reef fisheries should be founded upon scientific data set combining different types of indicators, some of which are biological and ecological indicators. The objective of the study were (1) to analyze trophic structure on reef fish communities in Semak Daun Island, (2) to examine population biology and exploitation on most favored reef fish, and (3) to review the inter-relation and response between reef fish resource with trophic level, population variables, and exploitation. The research was conducted in the patch reefs encircling Semak Daun Island, Kepulauan Seribu. There were seven (7) research sites representing the entire island system. Sampling for reef fish communities was conducted by underwater visual census and capture using gillnet and bamboo trap. Data analyses comprise of fish density, fish trophic level, and a set of population variables. Statistical test was performed to test the difference of fish abundance between sites and biomass of each trophic level, to analyze the influence of population variables to fish biomass, and the correlation between different trophic level. Research results revealed that fish communities in Semak Daun Island comprise of different trophic levels, from 2.10 to 4.00. The lowest fish density was presented at trophic level 2.51-3.00, dominated by Scarus ghobban (Scaridae). Growth coefficient (K) for dominant fish species ranged between 0.09-0.64 month-1, L∞ 49.13-190.05 mm. The range for mortality rate was 0.81-1.61 month-1, with natural mortality rate of 0.14-0.71 month-1. Exploitation rate in general was exceeding 0.5. The highest intensity of reef fish exploitation was performed using gill nets with dominant yields grouper (Serranidae, Epinephelus fuscoguttatus) and tusk fish (Labridae, Choerodon anchorago). Fish density featured to decrease its density in parallel to the elevation of fish trophic level. There also observed sharp decline in fish biomass at trophic level 2.51-3.00, followed by poor growth and low natural mortality, with excessing-optimum of fish exploitation rate. Such measures indicate that reef fish exploitation has put considerable pressure on reef fish resources in Semak Daun Island. Pattern of energy flow was constructed referring to fish diet and existing population dynamics, revealing that fish community at low trophic level (2.00-2.50) had significant contribution to support reef fish resources and greater impacted by the remaining trophic level, as well as contributed significantly to population variables. Fish biomass at this trophic level strongly correlated with higher trophic level (3.51-4.00). Therefore, the management of reef fisheries at high trophic level feature critical and significant in maintaining the stability of reef fish community at Semak Daun IslandSumberdaya ikan di Pulau Semak Daun mengalami tekanan akibat penangkapan berlebih (overfishing) dan tidak ramah lingkungan. Hal ini ditandai dengan penurunan kelimpahan, penurunan ukuran rata-rata individu hasil tangkapan, berkurangnya keragaman spesies hasil tangkapan, penurunan hasil tangkap per satuan upaya (CPUE) dan dominasi spesies berukuran relatif lebih kecil dengan nilai ekonomis yang lebih rendah. Penurunan ukuran dapat diakibatkan oleh selektivitas alat tangkap. Target penangkapan sering ditujukan pada individu berukuran lebih besar dan lebih tua sehingga menurunkan proporsi jumlah individu berukuran besar dan berumur lebih tua dalam populasi. Dengan demikian penangkapan mempengaruhi struktur umur dan struktur ukuran dalam populasi. Pada tingkat komunitas, pengaruh langsung penangkapan menyebabkan pergeseran pemangsa, mangsa, atau pesaing dari komunitas ikan tersebut. Pengaruh tersebut meliputi penurunan biomasa jenis yang semula melimpah dan peningkatan biomasa jenis lainnya yang selanjutnya mengakibatkan perubahan kelimpahan relatif spesies atau komposisi jenis dalam komunitas, dan selanjutnya merubah biomasa relatif pada berbagai trofik level. Untuk mengatasi permasalahan tersebut diperlukan upaya pengelolaan sumberdaya perikanan yang didasarkan pada suatu kajian ilmiah tentang struktur trofik pada komunitas ikan, dimulai dari tingkat trofik paling rendah hingga ikan. Tujuan penelitian ini adalah untuk mengkaji struktur trofik pada komunitas ikan, mengkaji parameter populasi dan eksploitasi pada ikan dominan, dan menganalisa hubungan dan respon dari sumberdaya sebagai akibat keterkaitan trofik level, dinamika populasi dan eksploitasi. Kegiatan penelitian difokuskan di perairan gosong karang sekitar Pulau Semak Daun yang dibatasi dengan tubir, dibagi dalam beberapa stasiun agar mewakili karakteristik seluruh lokasi penelitian. Jumlah stasiun pengambilan contoh ada tujuh stasiun, yaitu stasiun 1 sampai dengan 4 mewakili lokasi dengan karakteristik habitat terumbu karang, stasiun 5 lokasi di sekitar lamun, stasiun 6 lokasi pasir campur lamun dan stasiun 7 mewakili perairan dalam atau gobah. Pengambilan contoh di tiap stasiun dengan cara sensus visual bawah air (UVC) dan sampling menggunakan alat tangkap gill net dan bubu. Parameter yang diukur pada saat pengambilan contoh ikan adalah kepadatan, panjang total, berat, dan identifikasi jenis-jenis makanan. Selain itu dilakukan pengukuran kualitas air dan lingkungan di setiap stasiun. Analisis data dilakukan untuk mengetahui kelimpahan ikan, biomasa, trofik level, dan parameter populasi. Uji statistik dilakukan untuk mengetahui perbedaan kelimpahan dan trofik level antar stasiun
IMPLIKASI IUU FISHING DALAM PENGELOLAAN SUMBER DAYA IKAN DI INDONESIA
Full text linkPada tatanan dunia, regional, dan nasional, dewasa ini isu kegiatan yang berkaitan dengan IUU fishing adalah merupakan ancaman utama terhadap sediaan ikan. Telah banyak inisiatif international yang didukung oleh organisasi internasional seperti FAO telah menyiapkan International Plan of Action dari IUU Fishing. Walaupun jumlah negara yang mencoba mengembangkan National Plan of Action dari IUU Fishing terus bertambah, tetapi dalam beberapa hal, kegiatan IUU Fishing merupakan hal yang banyak terjadi dan merupakan ancaman nyata terhadap perikanan lokal. Adalah benar bahwa perhatian dunia terhadap IUU Fishing terus meningkat sebagai akibat yang nyata penurunan sediaan ikan dunia secara drastis. Perkiraan kasar secara keseluruhan menunjukkan bahwa paling tidak 30% dari hasil tangkapan perikanan dunia diperoleh dari kegiatan IUU Fishing. Ini memperlihatkan bahwa masalah IUU Fishing tersebut meningkat dengan kuat, terutama bila dilihat dari percepatan penurunan ketersediaan sumber daya perikanan. Tulisan ini menyajikan hal-hal yang berkaitan dengan pengkajian sediaan dan pengelolaan perikanan seperti juga halnya kegiatan IUU Fishing yang terjadi di Indonesia. Dampak IUU Fishing terhadap hasil pengkajiaan sediaan pada akhirnya digunakan sebagai informasi dasar untuk pengelolaan perikanan juga dibahas. Rekomandasi disampaikan dalam kaitannya untuk mengurangi kegiatan IUU Fishing dan meningkatkan pengkajian sediaan ikan dan pengelolaan perikanan.At global, regional, and national levels, issues associated with IUU fishing activities currently constitute a major world-wide threat to fisheries stocks. There have already been many international initiatives supported by international organizations such as the FAO which have been engaged in the International Plan of Action on IUU fishing. Although an increasing number of countries are trying to develop national plan of actions on IUU fishing, in many parts, IUU fishing practices are still common place and constitute a real threat to local fishers. Indeed, there is increasing global concern about IUU fishing practices due to the fact that global fish stocks are declining drastically. Approximate estimations suggest that overall at least 30% of world-wide fisheries catch is obtained from IUU fishing activities. This shows that the problem is increasingly severe, especially in view of the accelerating overall decline in available fisheries resources. This paper presents briefly regarding stock assessment and fisheries management as well as IUU fishing activities that undertake in Indonesian waters. The impact of IUU fishing to the result of stock assessment, that finally used as basic information for fisheries management is also discuss. Recommendation ismade in relation to eliminate IUU fishing activities and improvement of stock assessment and fisheries management
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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