The purpose of this project is to understand why the European eel population is declining. It will determine the capacity for endurance swimming and maturation of silver eels from different locations. Furthermore, the capability of yellow eels to transform into silver eels downstream will be investigated. Together with genetic characterisation, this information will provide knowledge on the reproduction capacity of silver eels in certain locations, an important parameter for the recruitment of the species. The knowledge gained here could be used in the future for eel fishery management and development procedures for artificial reproduction.
The objectives of the project are:
1) to study the capacity of the silver eel to swim to the spawning grounds. Swimming performance, high-pressure resistance and the effect of swimming on maturation are central themes
2) to develop a silvering index. This will allow the formulation of reliable decisions for eel ecosystems and eel fisheries management, for example when, and under what, conditions silver eels migrate.
3) to develop a maturation index. Silver eels are still in a pre-pubertal stage, the gonad development being heavily depressed. This is likely to be related to the 6 000 km they have to swim before reaching the spawning sites. Selection criteria for simulated maturation, and for new procedures, will be developed, either by long-term swimming, or by hormonal treatments.
Progress to Date
The project is progressing well. All the crucial milestones and deliverables were reached. The consortium convened twice and the collaborations have been very productive
The developed swimming fitness test has already been used as a tool to select good and poor swimmers for long-term simulated migration. The protocol was applied to determine the correlation between swimming fitness and hormone sensitivity. Tests with artificial maturation were carried out, and good quality eggs and sperm were obtained. In addition, some series showed good embryonic development after fertilisation.
FISHERIES AND AQUACULTURE
Scientist responsible for the project
Dr. GUIDO van den Thillart
Kaiserstraat 63 Box 9516
2300 RA Leiden
Netherlands (The) - NL
Phone: +31 715274248
Fax: +31 715274900
||01 November 2001
||1 896 040 €
|Total EC contribution
||1 498 661 €
|Web address of the project