Nofima reports

Rapport/Report 12/2016 - English summary

Lein, Ingrid

Publication details

Publisher: Nofima AS

Issue: 12/2016

Number of pages: 7

International Standard Numbers:
Printed: 978-82-8296-368-8

Open Access: green


This project was a continuation of some of the activities on egg production in Ballan wrasse initiated in the FHF-project LeppeProd (2011-2013). The goal of the present project was to contribute to an efficient and predictable production of high quality Ballan wrasse eggs. We wanted to develop a method for induction and synchronization of spawning in Ballan wrasse using hormone injections (GnRH). The plan was also to finalize a method for elimination of the sticky layer developing on the egg surface in contact with seawater. Elimination of the sticky layer gives more flexibility with regard to incubation methods and, more efficient egg disinfection. The last task was to clarify how many sperms/egg are needed to obtain high fertilization rates in Ballan wrasse, how long can sperm be stored cold (3-4°C) without reduction in fertilization and, investigate if Ballan wrasse milt is suited for cryopreservation. Unfortunately, the brood stock caught in 2011 gave poor quality eggs when the project started in 2014. Therefore, the brood stock was slaughtered during autumn 2011, and new brood stock was brought in June 2015. The new stock was caught at the same location and time as in 2011 and, transport and treatment after arrival to Nofima was similar to what was done in 2011. However, during June 2015, only a few, or none, females spawned naturally and the males produced small volumes of milt with very low sperm densities. We assume this happened because the brood stock matured late due to extraordinary low seawater temperatures in 2015. From others we know that the maturation in wild caught brood stock can stop due to stress if the fish is caught too early. Due to these problems, we were not able to carry out the planned activities. Thus, in agreement with FHF we terminated the project at the end of 2015.