July 10, 2010

Denmark university focuses on self-sustainable aquaculture

In a EUR5 million (US$6.3 million) research project called PRO-EEL, the Technical University of Denmark (DTU) is working to reproduce the European eel in captivity.

The European Commission (EC) is funding this project to establish a self-sustained aquaculture of eels in the continent in response to dramatically dwindling wild European eel inventories.

Eels in the PRO-EEL project receive hormonal treatment to develop gametes and fertilisation is made in vitro, as eels do not reproduce in captivity due to a hormonal inhibition of maturation.

The PRO-EEL project aims to broaden the knowledge on European eel (Anguilla anguilla) reproduction and enable successful maturation and offspring production. This includes choosing appropriate broodstocks, enhancing eggs and sperm quality and fertilisation methods and culture conditions favourable for the production of viable eggs and larvae.

Determining suitable feed for the eels and establishing feeding cultures of larvae will be particularly challenging, as scientists do not know what to feed these larvae. Findings show that eel larvae feed on extremely diverse marine organisms.

"The primary bottleneck in a controlled reproduction of eels concerns deficiencies in knowledge about their reproductive physiology and methods applied to induce and finalise gamete development," said the coordinator of the project, Jonna Tomkiewicz from DTU Aqua.

Gene technology and molecular methods will help obtain a regular and predictable production of viable eggs and larvae from broodstock eels fed enhanced diets.

Other challenges are the identification of suitable larval rearing conditions and initial feed for the larvae.

Japanese researchers recently produced offspring from captive-bred Japanese eel, thereby successfully finalising the life cycle of eel in captivity. As the Japanese eel is closely related to the European one, these results are promising for the success of the PRO-EEL project.

PRO-EEL will replace the use of wild glass eels as stocking material for aquaculture with fry raised under controlled conditions.