Back to search

HAVBRUK2-Stort program for havbruksforskning

Environmental requirements and welfare indicators for new cage farming locations and systems

Alternative title: Miljøbehov og velferdsindikatorer for nye lokaliteter og systemer

Awarded: NOK 8.0 mill.

Project Number:

267800

Application Type:

Project Period:

2017 - 2020

Partner countries:

The Future Welfare project addresses key knowledge gaps related to the behaviour and welfare of farmed salmon introduced by the rapid and recent development of an array of new farming systems and locations. These new farming systems attempt to reduce long-standing and intractable environmental problems such as salmon lice infestations and the escape of farmed fish. However, new knowledge is required to assess how these new farm types impact the behaviour and welfare of salmon. Future Welfare has first focused on developing fundamental knowledge on production environments, fish behaviour and welfare in new farming systems and locations using three case studies of existing and planned technologies (exposed traditional cages, lice-barrier skirt and snorkel cages, and submerged cages). It has then generated knowledge of the adaptive capacity of fish within these new farming systems, and also how this can be facilitated or encouraged for production and welfare benefit. Measurements of production efficiencies, lice levels, welfare and environment have been conducted in multiple cages with lice barrier technologies like skirt, snorkel and submerged cages. Thresholds for salmon and cleaner fish ability to tolerate water currents occurring more often in offshore farming have been extensively hammered out and is reviewed in a welfare perspective and used in up-to-date welfare guidelines. Maximum neutral buoyancy depth for salmon is revealed. In tanks and small-scale cages, the ability of salmon to be trained to cope better later in life shown. Salinity is a significant environmental factor that alters the lice-reducing efficacy of depth-based technologies such as snorkels. Generally, the new technologies do not reduce welfare of the salmon, when applied optimal and environment (e.g. oxygen) is kept within normal levels. However, even though submergence with air domes looks promising with normal behaviours, poorer performance has been noted due to the colder and hypoxic environment in depth at the test site. Submergence therefore still needs to be tested again for the full production cycle in both medium and commercial scale. Swimming behaviour (swim speed, surface activity, tilt angle) and total echo strength over time seem to be good candidates for future welfare indicator in some of the new cage technologies, on top of present operational welfare indicators (OWIs).

In exposed farming, salmon are well able to cope with both waves and currents. However, their ability depends on stocking density with higher biomass potentially leading to more difficulty in avoiding collisions in large waves, and if currents are also strong. Lice Barrier technology: salmon were mostly observed with their normal diurnal behaviour in cage. With the use of artificial light deep in the cage, combined with preferred sea temperature gradients, the salmon gather mainly to the same depths during day and night. Welfare was seen within normal ranges and vary with the seasons. Underwater farming: Some observed slower growth and poorer welfare of submerged fish due to periods of colder temperatures and low DO below 15 m deep, highlights further work is still required on better regulating the submerged farming cage environment. A numerical model simulating fish behaviour have been developed and tested successfully with field measurements data and observations.

The Future Welfare project will address key knowledge gaps related to the behaviour and welfare of farmed salmon introduced by the rapid and recent development of an array of new farming systems and locations. These new farming systems attempt to reduce long-standing and intractable environmental problems such as salmon lice infestations and the escape of farmed fish. However, new knowledge is required to assess how these new farm types impact the behaviour and welfare of salmon. Future Welfare will first develop fundamental knowledge on production environments, fish behaviour and welfare in new farming systems and locations using three case studies of existing and planned technologies (exposed traditional cages, lice-barrier skirt and snorkel cages, and submerged cages). We will generate knowledge of the adaptive capacity of fish within these new farming systems, and how this can be facilitated or encouraged for production and welfare benefit. Using results from each case study, we will adapt an existing standardized welfare assessment method to incorporate new welfare indicators and create a welfare assessment method suited for new farming systems. Finally, we will build a predictive biophysical model that integrates cage environments and fish behaviours to predict how new faming systems will affect fish behaviours and welfare. The predictive model will be made freely available to cage developers so that outcomes for fish can become central to technological design processes.

Publications from Cristin

No publications found

No publications found

Funding scheme:

HAVBRUK2-Stort program for havbruksforskning