News

Knowledge for sustainable aquaculture

"If we acquire knowledge early enough about undesired effects of aquaculture, then measures can be implemented in time," says Sigve Nordrum, chair of the HAVBRUK programme board. Sustainability is the main topic of the programme's latest newsletter.

Illustration Nytt fra HAVBRUK no. 2/2009 The newsletter ("Nytt fra HAVBRUK" no. 2/2009) profiles projects that are yielding knowledge to ensure the sustainable development of the aquaculture industry.

"Many of the projects funded under the HAVBRUK programme address various aspects of sustainability. This is essential to providing a knowledge base for debate, for measures to be implemented within the industry, and for management-related decisions," points out Dr Nordrum. "Early knowledge about undesired effects of aquaculture will enable us to take measures in time." He encourages project managers and participants to share their knowledge and join the debate.

Although the cod farming industry is currently facing a number of problems, Dr Nordrum remains optimistic, and is convinced that new knowledge will be the key to meeting many of these challenges. One such example is the problem of potential spawning in cod cages and subsequent interbreeding between production cod and wild cod - one of the topics highlighted in the latest newsletter.

Spawning in the cage

"Interbreeding between production cod and wild cod could represent a serious threat to the wild cod stock. At the same time, it could threaten the aquaculture industry, since biological diversity is required in order to selectively breed new generations of hardy, healthy production cod," warns researcher Knut E. Jørstad of the Institute of Marine Research, who is leading a project on this topic. His researchers have confirmed that cod do indeed spawn in their cages, that their eggs survive, and that the larvae journey far from the production sites.

Fish and pain

Photo cod The researchers are studying the cod's brain. (Photo: Nofima Marin) Sustainability also encompasses fish welfare, and the newsletter delves into the question of whether cod and other fish can feel pain. An international team of researchers is using MRI scanning to ascertain which part of the cod brain reacts to unpleasant stimuli.

The project manager, researcher Øyvind Aas-Hansen of Nofima Marin, says, "Our experiments will answer the question of whether fish actually feel pain, providing a better knowledge base for legislation. As a major fisheries and aquaculture nation, Norway needs to know how to treat fish as humanely as possible."

Another article deals with effective methods of pre-slaughter anaesthesia once the ban on CO2 use takes effect on 1 January 2010. Both electrical stunning and mechanical blow are better than the CO2 method, according to Bjørn Roth of Nofima, who has studied these methods' advantages and disadvantages. "With both of these methods, it is essential to treat the fish with care," he emphasises, citing the clear correlation between the pre-slaughter handling of live fish and their product quality.

In deep waters

Aquaculture facilities have become both larger and more environmentally sound in recent years. Proper placement of production facilities will also make them more sustainable, according to the Institute of Marine Research's Arne Ervik, who heads the major cooperative project Ecosystem Responses to Aquaculture Induced Stress (ECORAIS).

The project, now in its start-up phase, currently has more questions than answers. The overall objective is to generate a knowledge base for sustainable management along the Norwegian coast. "Based on knowledge of how aquaculture sites affect the ecosystem," explains Dr Ervik, "we will be able to make calculations on how much environmental stress a given area can withstand - and where the facilities should be placed."

Wild salmon are surviving

Ole Kristian Berg observes differences between stocks of wild salmon. (Photo: Per Harald Olsen) There have long been concerns that production salmon could diminish biological diversity among wild salmon. The newsletter features an interview with Ole Kristian Berg of the Norwegian University of Science and Technology (NTNU), who is studying the differences between salmon from Norway's northern and southern waters.

Professor Berg makes no attempt to downplay the problems posed by escaped production salmon and he advises continued caution. Nevertheless, he has found that major differences still exist between the wild salmon stocks of Norwegian waters after 30 years of aquaculture activities.

"A natural selection appears to occur that mitigates the impact of escapes," he says. Findings are currently based on morphological studies of expressed physical characteristics. In the project's next phase genetic studies will be conducted to examine more closely the variations between the various salmon stocks.

Looking for offspring from genetically marked cod. (Photo: Skjalg Ekeland)