Length-weight relationships of three freshwater eel species from the floodplain ecosystems of northeastern Bangladesh

This study reports the Length-weight relationships (LWRs) of three freshwater eel species from the northeastern wetlands of Bangladesh. A total of 2684 specimens of Mastacembelus armatus, Macrognathus aculeatus and Macrongathus pancalus were sampled between in the months of June and December 2019 using different nets and eel traps at every 4 days working schedule per month. The calculated a values of the LWRs ranged from 0.008 to 0.020; b values ranged from 2.35 to 2.70, and r2 from 0.907 to 0.944. The lowest values of regression coefficient found for M. aculeatus and the highest for M. pancalus. All the regression parameters for LWRs found highly significant (p ˂ 0.001). These results will provide baseline information for sustainable management and conservation of the fisheries resources in the northeastern floodplain region of Bangladesh.

The Toxic Effect of Ametryn on Behaviour and Histopathological Changes of Freshwater Eel (Monopterus Albus) [Pengaruh Toksik Ametryn terhadap Perilaku dan Perubahan Histopatologis Belut AirTawar (Monopterus Albus)]

A study on the toxicity of herbicides was investigated with emphasis on behaviour and histopathological effects. Ametryn commonly used to control weeds in the paddy field. The effect of ametryn on fish especially Monopterus albus was unknown. This study aims to determine the acute toxicity of ametryn and its effects on the behaviour of the eels. The adult M. albus were exposed to 0, 0.75, 1.5 and 3.0mg/L of ametryn for 96 hours under laboratory conditions. The eels showed symptoms of abnormal behaviour responses during the exposure which are agitated behaviour, respiratory distress, and abnormal nervous behaviour. Mortality was increased by increasing the concentration of ametryn. This present study showed the effect of ametryn on kidney tissue changes. Hemorrhage and distribution of hemosiderin, hydropic degeneration, granular degeneration, tubular necrosis, narrowing tubular lumen and necrosis were major histopathological effects that occurred during the exposure to ametryn. In conclusion, ametryn is very sensitive to Monopterus albus. In lower concentration, they showed changes in behaviour and effect their organs. AbstrakStudi tentang toksisitas herbisida yang diamati dengan penekanan pada perilaku dan dampak histopatologis. Ametryn biasanya digunakan untuk mengawal rumpai di sawah padi. Kesan ametryn pada ikan terutama belut tidak diketahui. Penelitian ini bertujuan untuk menentukan toksisitas akut ametryn dan dampaknya terhadap perilaku belut. M. albus dewasa terpapar pada 0, 0.75, 1,5 dan 3,0mg / L ametryn selama 96 jam pada kondisi laboratorium. Belut menunjukkan gejala respons perilaku abnormal selama paparan yaitu gelisah, gangguan pernapasan, dan perilaku saraf abnormal. Kematian meningkat seiring meningkatnya konsentrasi ametryn. Penelitian ini menunjukkan dampak ametryn pada perubahan jaringan ginjal. Perdarahan dan distribusi hemosiderin, degenerasi hidropik, degenerasi granular, nekrosis tubular, penyempitan lumen tubular dan nekrosis adalah dampak histopatologis utama yang terjadi selama paparan ametryn. Kesimpulannya, ametryn sangat sensitif terhadap Monopterus albus. Dalam konsentrasi rendah, belut menunjukkan perubahan perilaku dan kesan pada organ.

The effect of temperature on the physiological condition and growth performance of freshwater eel elver Anguilla bicolor bicolor McClelland, 1844

<p align="center"><strong>ABSTRACT</strong></p><p align="center"> </p><p>This study aimed to analyze the effect of water temperature on the physiological condition and growth performance of freshwater eel elver<em> Anguilla bicolor bicolor </em>(McClelland, 1844). This study was conducted in March 2017 at the Physiology Laboratory of Aquatic Animal, Faculty of Fisheries and Marine Sciences, Bogor Agricultural University. The study used a completely randomized design with five different levels of temperature (22^°C, 24^°C, 26^°C, 28^°C, and 30^°C) as treatments with two replications. The size of elver was 2‒3 g. Fish were fed with 1 mm pellet containing 45% of protein. The feeding level was 7 % of fish biomass and the feeding frequency was two times a day. The results showed that temperatures range from 24‒30^°C could be used for freshwater eel elver rearing and 28‒30^°Cwere the best temperatures to support survival and growth performance of eel elver. A temperature of 24^°C was the best temperature that could reduce the metabolism rate and did not cause stress on the elver.</p><p> </p><p>Keywords: elver, physiological conditions, growth performance, metabolism, temperature</p><p> </p><p> </p><p align="center"><strong>ABSTRAK</strong></p><p align="center"><strong> </strong></p><p>Penelitian dengan tujuan menganalisis pengaruh suhu terhadap kondisi fisiologis dan kinerja pertumbuhan <em>elver</em> ikan sidat (<em>Anguilla bicolor bicolor</em> McClelland, 1844) telah dilakukan pada bulan Maret 2017 di Laboratorium Fisiologi Hewan Air FPIK IPB. Penelitian menggunakan rancangan acak lengkap dengan lima perlakuan suhu berbeda (22^°C, 24^°C, 26^°C, 28^°C, dan 30^°C) dengan masing-masing dua ulangan. Ukuran benih yang digunakan 2‒3 g. Pakan yang diberikan berupa pellet berukuran 1 mm dengan kadar protein 45%. Jumlah pakan yang diberikan (FR) adalah 7% dari biomassa ikan dan diberikan dua kali sehari. Hasil penelitian menunjukkan bahwa kisaran suhu 24‒30^°C dapat digunakan dalam pemeliharaan <em>elver</em> ikan sidat, dan suhu 28‒30^°C merupakan suhu yang sangat baik untuk mendukung kelangsungan hidup dan pertumbuhan <em>elver</em> ikan sidat. Suhu media 24^°C adalah suhu terbaik yang dapat menekan laju metabolisme dengan tidak menyebabkan stres pada <em>elver </em>ikan sidat.</p><p> </p><p>Kata kunci: <em>elver</em>, kondisi fisiologis, kinerja pertumbuhan, metabolisme, suhu</p><p> </p><p> </p>

SPECIES COMPOSITION OF FRESHWATER EELS (Anguilla spp.) IN EIGHT RIVERS FLOWING TO PALABUHANRATU BAY, SUKABUMI, INDONESIA

Freshwater eel (Anguilla spp.) is a catadromus fish that migrates from freshwater into seawater for spawning and return to freshwater during larvae stage to grow. The objective of this study was to determine species composition of tropical freshwater eels based on morphology collected from several rivers flowing in to the Palabuhan Ratu Bay. Young, adult, and glass eels were caught in August 2014 until Desember 2014. Glass eels were only caught in Cimandiri River. Freshwater eels were classified by ano-dorsal length (AD) divided by total length (TL), cluster analysis, and discriminant analysis based on morphometric data. The results showed different AD/TL of young and adult, i.e., 1.93±0.51 for A. bicolor bicolor, and 16.99±0.65 for A. marmorata, and three different AD/TL of glass eels i.e.,1.72±1.05 for A. bicolor bicolor6.60±1.79 for A. nebulosa nebulosa, and 15.07±1.04 for A. marmorata. Cluster analysis showed three groups of population characters of young and adult eels i.e. A. bicolor bicolor (2 groups) and A. marmorata (1 group). Discriminant analysis showed three groups of glass eels population i.e., A. bicolor bicolor, A. nebulosa nebulosa, and A. marmorata. Morphological identification showed that young and adult eels in Cibareno and Citepus rivers had two species i.e., A. bicolor bicolor and A. marmorata. Glass eels from Cimandiri river had three species i.e., A. bicolorbicolor, A. nebulosanebulosa, and A. marmorata. A. bicolor bicolor was found in each rivers and as a dominant species in Palabuhan Ratu Bay.Keywords: A. bicolor bicolor, A. marmorata, A. nebulosa nebulosa, species composition

Feeding rate of freshwater eel Anguilla bicolor bicolor: at the body weight of 1–2 g

<p class="BasicParagraph" align="center"><strong>ABSTRACT</strong></p><p class="BasicParagraph" align="center"><strong> </strong></p><p class="Pa3">The aim of the research was to determine feed requirement for the maintenance, optimum, and maximum growth of freshwater eel (<em>Anguilla bicolor bicolor</em>) seed (1–2 g body weight). Feed used in this research was KRA feed with 46% protein content, with different feeding level (FR) at 0%, 5%, 10%, and 15% of fish biomass. The experiment was conducted in 30 days. Parameters measured were survival and <em>s</em>pecific growth (SGR). The results showed that survival of fish in all treatments were 100%, except in fish fed on 15% of biomass (only 96). Fish growth with feeding of 0%, 5%,10%, and 15%, were -1.06%; 0.42%; 0.73%; and 0.19%, respectively. Based on the analysis of the relationship between feeding level and growth, the feed requirement for maintenance, optimum, and maximum growth in 1–2 g freshwater eel seed were 3.3%; 7.0%; and 9.5% of the biomass, respectively.</p><p class="Default"> </p><p>Keywords: eel seed, feed requirement, growth</p><br /><p class="BasicParagraph"> </p><p class="BasicParagraph" align="center"><strong>ABSTRAK</strong></p><p class="BasicParagraph"><strong> </strong></p><p class="Pa3">Penelitian dilakukan dengan tujuan untuk mendapatkan kebutuhan pakan untuk <em>maintenanc</em>e, dan untuk pertumbuhan optimum serta maksimum benih ikan sidat (<em>Anguilla bicolor bicolor</em>) (bobot tubuh 1–2 g). Pakan yang digunakan pada penelitian ini adalah pakan KRA dengan kadar protein 46%, dengan tingkat pemberian pakan 0%, 5%, 10%, dan 15% dari bobot biomassa ikan. Pemeliharaan berlangsung selama 30 hari. Parameter yang diukur meliputi sintasan (STS) dan laju pertumbuhan spesifik (LPS). Hasil penelitian menunjukkan bahwa STS benih ikan sidat selama pemeliharaan, memiliki nilai yang baik (100%) kecuali pada pemberian pakan 15% (hanya 96%). Laju pertumbuhan benih ikan sidat selama pemeliharaan dengan pemberian pakan 0%, 5%, 10%, dan 15% berturut-turut adalah -1,06%; 0,42%; 0,73%; dan 0,19%. Berdasarkan analisis hubungan antara tingkat pemberian pakan dan laju pertumbuhan spesifik, maka kebutuhan pakan <em>maintenance</em>, pertumbuhan optimum dan maksimum benih ikan sidat berukuran 1–2 g berturut-turut adalah 3,3%; 7%; dan 9,5% dari biomassa.</p><p class="Default"> </p><p class="Pa3">Kata kunci: benih ikan sidat, kebutuhan pakan, pertumbuhan</p>