Assessing the freshwater distribution of yellow eel

Abstract

In the global context of the decline in wild species, modeling the distribution of populations is a crucial aspect of ecological management. This can be a major challenge, especially for species, such as the European eel, that have complex life cycles, exhibit cryptic behavior, or migrate over long distances. A review of the literature suggests that eel size data could be used to assess and analyze freshwater distribution of eel. We argue that analyses based on small yellow eels (≤ 300 mm) along the longitudinal course of rivers could provide a valuable tool for population monitoring. We propose a standardized catchment recruitment index and a colonization index based on the probability of occurrence (presence/absence data) using logistic models for different size classes. The model developed here provides a convenient guide for assessing yellow eel stages in freshwater areas, and should have concrete applications for management of the species. RÉSUMÉ Évaluation de la distribution des anguilles jaunes en eau douceDans le contexte actuel de déclin des espèces, la modélisation de la distribution des populations est une étape importante pour la gestion de la biodiversité. Cependant, cette modélisation peut s'avérer difficile, particulièrement pour les espèces qui, comme l'anguille européenne, possèdent des cycles de vie complexes, ont un mode de vie cryptique ou effectuent de grandes migrations. Un examen de la littérature suggère que la taille des anguilles peut être utilisée comme critère pour évaluer et analyser la distribution des anguille en eau douce. Nous suggérons que l'examen des patrons de distribution des petites anguilles (≤ 300 mm) le long des réseaux hydrographiques peut fournir des informations précieuses pour le suivi des populations. Nous proposons un indice standardisé de recrutement et de colonisation des bassins versants sur la

Efficient Fishing Method to Control the Population of Rice Eel, Monopterus albus (Synbranchidae) in Rice Fields in Cagayan Valley, Philippines

“…This means that the longer time EF will be used, the higher the catch. Studies by Laffaille et al (2005), Laffaille (2008), andScott (2011) support the findings of this study, especially on quantitative assessments of population size. However, there are limitations to using EF as a fishing gear for this fish.…”

Comparison of point and transect-based electrofishing to sample American eel (Anguilla rostrata) in wadeable riverine habitats

“…Electrofishing is recognized as an efficient method to characterize eel distribution patterns, sample various sizes of eel, and obtain quantitative assessments of population size (Naismith and Knights 1993;Lobon-Cervia et al 1995;Laffaille et al 2005;Lasne and Laffaille 2008). Currently, transect-based boat-electrofishing surveys are used to monitor a Corresponding author: reid.scott@ontario.ca eels stocked into Lake Ontario (Bay of Quinte) and the upper St. Lawrence River.…”

“…However, the use of block-nets is impractical for larger watercourses. Point-sampling (PASE: point abundance sampling by electrofishing, Nelva et al 1979) is an alternate strategy to characterize eel populations and is applicable to a wider range of watercourse sizes (Lafaille et al 2005;Lasne et al 2008). …”

Hard times for catadromous fish: the case of the European eel (Anguilla anguilla, L. 1758)

“…The European eel A. anguilla is a panmictic species (Palm et al, 2009;Enbody et al, 2021) distributed across most of the coastal countries in Europe and North Africa and spanning the entire Mediterranean basin (ICES, 2018). Because the complex life cycle, the cryptic behavior, and body shape features of eels, results hard to find appropriate and standardized sampling technique for the monitoring of the European eel in several aquatic environments (Naismith and Knight, 1990;Lasne and Laffaille, 2009). Furthermore, many aspects of the resident stage of eels in freshwaters during their growth phase are still insufficiently understood such as ecology in terms of space and time use (Feunteun et al, 2003;Imbert et al, 2010).…”