Here's the last report in The Aquaculturists Trout Focus from International Aquafeed magazine.
I hope you've enjoyed the articles this week and got a good insight into this fascinating species.
There are a few more trout pieces which didn't make it onto the blog - you can read them here.
For the final feature, I've chosen the UK perspective, written by David Bassett of the British Trout Association.
|English: Extruded feed pellets (Photo credit: Wikipedia)|
Perspectives on UK trout farming and aspects relating to fish feed
by David Bassett, British Trout Association
UK trout farming differs to some other countries in that the UK employs a number of different production methods. Trout are farmed in freshwater open net pens, earth ponds and concrete raceways and are also farmed in open net pens in marine water off the west coast of Scotland. UK trout farmers also employ recirculation technology – most commonly as partial recirculation in hatchery facilities rather than the entirely closed recirculation sites as may be seen elsewhere.
The UK primarily produces rainbow trout, although brown trout are farmed too. Both species may be farmed to organic standards, and consequently use organic feeds, although this market remains small, producing only in the hundreds of tonnes. Both brown and rainbow trout are farmed for the restocking market (i.e. sale of live fish for stocking to fisheries) although the majority of fish that are farmed are for the table market.
Production tonnages vary annually, but current official statistics suggest that circa 11,000 tonnes of table trout are farmed each year, with a further circa 3,500 tonnes for restocking. Large trout production, those fish farmed in marine water, is increasing, with 2011 production being estimated at 2,000 tonnes, up from circa 1,600 tonnes in 2010.
Fish feed accounts for approximately 50 percent of production costs, and so is of paramount importance to UK producers. Through both European Union and UK domestic legislation, fish feeds, their composition and their use, are tightly regulated. The vast majority of trout farms source feed from the major commercial suppliers. Skretting has the largest market share, although other suppliers include EWOS, Biomar, Le Gouessant and Aller Aqua. However, whilst costs are high, trout farmers seek value for money and a return in terms of performance and as such would prefer to pay for a top quality feed in that this is a better investment in the long term resulting in a better yield and healthier fish.
Feed compositions vary between manufactures and specific formulations / diets. The major source of protein continues to be fish meal. Increasingly, producers seek to be able to vary the inclusion rates in diets of such ingredients as fish and vegetable oils. With the global commodity index affecting the price of key ingredients, trout farmers support feed manufactures in their attempts to operate using as wide a basket of ingredients as possible, to optimise variations in the commodity market.
With the exception of fish farmed to organic standards, the UK market prefers fish that is “pink” fleshed. As such, astaxanthin on canthaxanthin are included in the formulation of diets.
Most UK feeds for the table market avoid using land animal protein. Although permitted to do so by law, retail buyers seem reluctant to purchase fish fed using such diets. However, research undertaken by industry and other third parties suggests that there is little to no opposition to the inclusion of such protein sources on the part of the consumer / general public, who remain generally unconcerned about the diets fed to farmed fish.
In common with other sectors, 'sustainability' is a term that is used increasingly often with regard to fish farming and fish feeds. Whilst a definition of sustainability is always hard to achieve, it would be fair to suggest that much greater emphasis is now being placed upon such issues as Fish In Fish Out (FIFO). As a trade association representing the UK farming industry, the British Trout Association is increasingly liaising with feed companies and NGO organisations over issues relating to the inclusion percentages of fish meal and fish oil in diets, and the origin of the fish meal and fish oil that is used. It is predicted that greater emphasis will be placed upon such issues in the future, with certain certification schemes placing greater emphasis on the sustainability imprint of all aspects of production. How much importance consumers attach to this has yet to be demonstrated.
UK fish farming is strictly regulated in relation to discharges into the aquatic environment. As such, farmers pay close attention to feed conversions ratios and associated nutrient discharge and suspended solids. Whilst feed conversion ratios vary across the UK, given the wide range in production systems, water temperatures and other variables, feed conversion and feeding protocols have continued to improve in sophistication and understanding with reported ratios varying from under 1:1 (typically 0.95) to 1.2 :1.
UK trout farmers enjoy a close and mutually beneficial working relationship with commercial fish feed manufacturers and as an industry we continue to work together to be at the forefront of trout production.