Abstract

European eels (Anguilla anguilla L.) has a great dispersion from Sargasso Sea to across the Europe and North Africa. Their population have decreased dramatically over the years and listed in IUCN as critically endangered. Stock estimation is one of the important issues in order to sustainable management of this species. Last decades, researchers have focused various studies which based on monitoring of various life stages of eels. Manual counting methods with ladder traps is commonly used based on collection of glass and elver stages of eels from the natural habitats while their migration to upward of streams. During their special migration pattern, a counting device on the eel ladders can be designed so that the eels may be counted while passing through this device. The offered prototype was designed for eel ladders which was briefly, powered by an open-source electronics platform, Light Dependent Resistor (LDR) and 650 nm Laser light were used to count elver eels. Several trials were conducted to test this prototype and results were promising. This study aimed to explain features of prototype and working principle of elver counter. Designed prototype has several advantages such as usable with eel ladders, easy to customisation and affordable characteristics. However, this device needs some improvements in order to effective usages in the field.