scholarly journals The commercial push net fisheries for glass eels in France and its handling mortality

2021 ◽  
Author(s):  
Janek Simon ◽  
Fabien Charrier ◽  
Willem Dekker ◽  
Nicolas Belhamiti
Keyword(s):  
Glass Eels

Challenges to quantifying glass eel abundance from large and dynamic estuaries

2017 ◽  
Vol 75 (2) ◽  
pp. 727-737 ◽  
Author(s):  
Sarah Walmsley ◽  
Julie Bremner ◽  
Alan Walker ◽  
Jon Barry ◽  
David Maxwell
Keyword(s):  
Large Scale ◽  
Anguilla Anguilla ◽  
Commercial Fishing ◽  
European Eel ◽  
Estuarine System ◽  
Glass Eel ◽  
The North ◽  
Adequate Sampling ◽  
South Shore ◽  
Glass Eels

Abstract European eel Anguilla anguilla recruitment into the rivers of the northeastern Atlantic has declined substantially since the 1980s. Monitoring of recruiting juveniles, or glass eels, is usually undertaken in small estuaries and rivers. Sampling of large-scale estuaries is rare, due to the size of the sampling area and the resources needed to provide adequate sampling levels. Here we describe surveys for glass eels in the UK’s largest estuarine system, the Severn Estuary/Bristol Channel. We sampled across a 20 km-wide stretch of the estuary in 2012 and 2013, using a small-meshed net deployed from a commercial fishing trawler, and the surveys yielded over 2500 glass eels. Eels were more abundant in the surface layer (0–1.4 m depth) than at depth (down to 8.4 m depth), were more abundant close to the south shore than along the north shore or middle of the estuary, and were more abundant in lower salinity water. Numbers were higher in the second year than in the first and eels were more abundant in February than April. The difficulties and logistics of sampling in such a large estuary are discussed, along with the level of resources required to provide robust estimates of glass eel abundance.

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

2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Agus Alim Hakim ◽  
M Mukhlis Kamal ◽  
Nurlisa A Butet ◽  
Ridwan Affandi
Keyword(s):  
Cluster Analysis ◽  
Discriminant Analysis ◽  
Species Composition ◽  
Dominant Species ◽  
Morphological Identification ◽  
Morphometric Data ◽  
Freshwater Eel ◽  
Glass Eels ◽  
Freshwater Eels ◽  
Tropical Freshwater

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

scholarly journals Recruitment and abundance estimation of glass eel genus Anguilla in three large estuaries on the coast of Sukabumi West Java

2021 ◽  
Vol 322 ◽  
pp. 01037
Author(s):  
Triyanto ◽  
Gadis Sri Haryani ◽  
Mohammad Mukhlis Kamal ◽  
Iwan Ridwansyah ◽  
Fauzan Ali ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Rainy Season ◽  
Dominant Species ◽  
Water Discharge ◽  
Abundance Estimation ◽  
West Java ◽  
Glass Eel ◽  
The Indian Ocean ◽  
Glass Eels

The rivers on the Sukabumi Coast flow into the Indian Ocean. Three major rivers, namely the Cimandiri River, Cikaso River, and Cibuni River, are sources of glass eel fishing. This study aims to determine the recruitment and estimate of glass eel abundance for future glass eel management. The study was conducted from November 2020-April 2021. Estimation of glass eel abundance was carried out using a fyke net. The glass eel calculation is determined based on the number of glass eels caught, the water discharge entering the fyke net, the water discharge in the estuary, and other variables. The results showed that glass eel recruitment began at the beginning of the rainy season in November 2020 and lasted at the end of the study in April 2021. Anguilla bicolor bicolor is a dominant species of glass eel found in the three river estuaries. The estimated abundance of glass eel was approximately 2,583,438-13,556,650 ind./year or 326,24-1,812 kg/year. The abundance of glass eels at the estuary of Cimandiri River was higher than that of the estuary of Cibuni River and the estuary of Cikaso River.

scholarly journals Analisis Orde Sungai Dan Distribusi Stadia Sebagai Dasar Penentuan Daerah Perlindungan Ikan Sidat (Anguilla spp.) Di DAS Cimandiri, Jawa Barat

2020 ◽  
Vol 3 (1) ◽  
pp. 1-9
Author(s):  
Agus Alim Hakim ◽  
Mohammad Mukhlis Kamal ◽  
Nurlisa Alias Butet ◽  
Ridwan Affandi
Keyword(s):  
Glass Eels

Sungai merupakan habitat makhluk hidup dimana terjadi hubungan timbal balik antara makhluk hidup dengan lingkungannya. Sungai yang merupakan habitat ikan sidat (Anguilla spp.) harus tetap terjaga agar pertumbuhan dan perkembangan tidak terganggu serta keberadaannya tetap lestari. Ikan sidat pada stadia larva akan bermigrasi dari laut ke perairan sungai hingga hulu dan setelah dewasa akan kembali ke laut untuk memijah. Penelitian ini bertujuan untuk menganalisis orde sungai dan mengkaji distribusi stadia ikan sebagai dasar penentuan daerah perlindungan ikan sidat (Anguilla spp.) di DAS Cimandiri, Jawa Barat. Penelitian ini dilakukan pada bulan Desember 2014 dan April 2015 meliputi tracking sungai (pengamatan habitat sungai, pengamatan aktivitas penangkapan, dan wawancara), analisis orde sungai, dan penentuan distribusi tiap stadia ikan sidat. DAS Cimandiri memiliki panjang sebesar 69,5 km dengan komposisi sungai permanen (permanent) dan sungai periodik (intermittent) memiliki orde sungai dari 1 hingga 7. Terdapat 56 sungai permanen bagian DAS Cimandiri yang merupakan sungai dengan orde sungai 1. Sungai dengan orde sungai 1 merupakan bagian hulu yang kondisi habitat dan perairannya masih baik. Beberapa dari bagian sungai yang memiliki orde sungai 1 dapat ditetapkan sebagai daerah perlindungan ikan sidat (Anguilla spp.). Distribusi berdasarkan stadia menunjukkan bahwa ikan sidat memiliki komposisi stadia yang tercampur, tetapi glass eels terdistibusi hanya pada 5 km dari arah laut. Adanya perbedaan stadia dari setiap bagian sungai maka diperlukan pengelolaan yang berbeda pula pada masing-masing bagian sungai tersebut.

scholarly journals Isolation and identification of bacteria and parasites in glass eel (Anguilla spp.)

2021 ◽  
Vol 322 ◽  
pp. 02012
Author(s):  
Septyan Andriyanto ◽  
Hessy Novita ◽  
Tuti Sumiati ◽  
Taukhid
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Prevalence Rate ◽  
Bacterial Species ◽  
Bacterial Identification ◽  
Biochemical Method ◽  
Isolation And Identification ◽  
Glass Eel ◽  
Pathogenic Agent ◽  
Identification Of Bacteria ◽  
Glass Eels

The disease is the main agent that causes mortality of fish, especially during seed stages. The research aimed to find out bacteria and parasitic speciesin glass eel, Anguilla spp. Bacterial identification was carried out by a biochemical method. The prevalence of bacterial species was calculated using the El-Gohary et al. (2020) formula, while the results of bacterial identification from glass eel were Aeromonas spp., Vibrio spp., Enterococcus spp., Staphylococcus spp., Planococcus spp., Lactobacillus spp., Listeria spp., Citrbacterfreundii, Neisseria spp., Pseudomonas aeruginosa, Kurthia spp., Streptococcus spp., and Corynebacterium spp. It was found that the five highest prevalence rate was for Listeria spp. (39.64%), followed by Aeromonas spp. (26.13%), Staphylococcus spp. (16.22%), Corynebacterium spp. (5.41%), Lactobacillus spp. (2.70%), and the lowest prevalence rate was Streptococcus spp. (0.90%). The type of parasitic pathogen obtained was Trichodina spp. (2,70%), Dactylogyrus spp. (2,70%) and Gyrodactylus spp. (2,70%). Bacterial and parasites identified in glass eels need further verification on the epizootiology characteristic of each pathogenic agent.

scholarly journals Species composition of glass eels (Anguilla spp.) recruiting to the Palu River, Central Sulawesi

2018 ◽  
Author(s):  
Novalina Serdiati ◽  
Samliok Ndobe ◽  
Abigail Moore ◽  
Deddy Wahyudi
Keyword(s):  
Species Composition ◽  
Dna Analysis ◽  
Temporal Patterns ◽  
Clove Oil ◽  
Analysis Method ◽  
Substantial Variation ◽  
Anguilla Marmorata ◽  
Glass Eels ◽  
Central Sulawesi ◽  
Tropical Eel

Demand for tropical eel seed has been increased and many tropical eel populations are under pressure. To conserve eel biodiversity and manage eel populations sustainably, it is necessary to identify eel species and their recruitment patterns at regional and watershed scales. The research objective was to determine the species composition and temporal recruit-ment patterns of glass eels recruiting to Palu River in Central Sulawesi. Glass eels sampling were conducted in January-April 2009, May-November 2010 and April-December 2011. Identification under anaesthetic (15-17.5 ppm clove oil solution) was based mainly on the number of ano-dorsal vertebrae (ADV). Species composition was dominated by two commercially species, Anguilla marmorata and A. bicolor pacifica with substantial variation and no clear temporal patterns. Specimens of other species that important from conservation and biodiversity aspects were present at each month but cannot be accurately identified using the ADV method. DNA analysis method is required to identify these specimens.

Eels at the Edge: Science, Status, and Conservation Concerns

2009 ◽  
Keyword(s):  
East Asia ◽  
Early Life History ◽  
Kuroshio Current ◽  
Japanese Eel ◽  
North Equatorial Current ◽  
Mariana Islands ◽  
The North ◽  
Management Plans ◽  
Equatorial Current ◽  
Glass Eels

Abstract.—The Japanese eel, Anguilla japonica, is an important food fish in East Asia, and catches of glass eels and of eels in freshwater appear to have declined dramatically in recent decades, causing increasing concern for the health of wild stocks. During that time, research efforts to understand its biology have progressed considerably. The spawning area was successfully outlined to the west of the Mariana Islands in 1991, and other research suggests that their recruitment success may be related to El Niño events, which appear to affect the transfer of leptocephali from the north equatorial current into the Kuroshio Current. Otolith microstructure and microchemistry studies have revealed various aspects of their early life history that relate to their oceanic larval migration. The discovery of sea eels that live in marine habitats without entering freshwater may change the common understanding of freshwater eel ecology and affect management plans. Most genetic studies suggest that the Japanese eel is composed of a single panmictic population throughout East Asia. Therefore, international management is needed among the countries of China, Taiwan, Korea, and Japan, where glass eels recruit from a common stock and are used extensively for aquaculture.

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