Possible salmon breeding breakthorugh – Fishfarmer Magazine

Possible salmon breeding breakthorugh08 June, 2011 –

RESEARCHERS in Norway are working on possible measures which could  improve the lives of farmed salmon and simultaneously increase production.

The country’s Institute of Marine Research believes that by releasing feed below the surface and using underwater lights, it is possible to lure the fish away from the sea lice larvae on the surface, while greater monitoring could make it possible to optimise the environment. If simple procedures are also developed to spot abnormal behaviour, fish farmers will be able to discover signs of disease at an earlier stage.

These proposals for possible measures are based on the results of many years’ work. The scientists have described in detail how salmon behave and respond to the cage environment, and how fish farmers can best use that knowledge to increase production.

Frode Oppedal, researcher and project manager at the Institute of Marine Research said: “With  more than 20 years of data and observations, we now have a better overall understanding of how cage environments vary and how salmon react to them. If fish farmers make use of this knowledge, it will allow them to break new ground in terms of cage environments, feeding regimes, the use of light, production efficiency, delousing and salmon welfare.”

The Institute says that it is normal for the environment inside a cage to vary considerably over time and depending on the water depth. The depth at which salmon swim and the fish density depend on a number of factors including  temperature, oxygen levels, salinity, currents, light, feeding regimes, and chemicals. These behavioural choices mean that the full volume of the cage is not used, and that fish density is greater at some depths than at others.

Based on this work, two new projects have been granted funding by The Research Council of Norway this year. They will focus on areas such as how individual fish experience the cage environment and the consequences of this, as well as tolerance levels of salmon of different sizes to variations in oxygen concentration and water currents