When does a Sea Pen become an Aquarium?
Multi-species feeding strategies from the aquarium experts
World Feeds Ltd has been making huge strides improving cleaner fish health, welfare and efficacy against sea lice. Their unique VAF Feed Blocks have been embraced by 6 of the 7 largest salmon producers in Scotland, with major farms in Norway also on board to reap the multitude of benefits their feeding strategies offer for what are essentially multi-species enclosures. Acknowledging concerns about the welfare of cleaner fish in commercial salmon pens, World Feeds introduced the VAF Feed Block as a hugely innovative, strategic and effective solution.
The company operates on the simple premise of “improving the way fish are fed” and carry a storied history developing pioneering, practical methods of feed delivery for vast multi-species exhibits in the public aquarium industry. They maintain that providing fish with the optimum means of obtaining the feed is of equal importance to the quality of the nutritional content itself. Their specialist aquatic feeds and strategies are trusted by many of the largest public aquariums worldwide. Dubai Mall Aquarium & Underwater Zoo, which houses an 11-million-litre multi-species ocean reef tank, have exclusively used World Feeds products since inauguration in 2008. They now feed over 30,000 fish of 200+ species with a carefully selected mix of World Feeds’ range of diets – recognizing the nutritional and welfare benefits to their fish, as well as the logistical and financial advantages for the business.
World Feeds designs and develops efficient solutions to overcome the challenges of feeding multi-species enclosures. They produce highly digestible feeds, from flakes, pellets and micronized flake particles for filter feeders to grazers and feed blocks, even including a unique and innovative technique for feeding sharks. Most pertinent to the aquaculture industry are the company’s distinctive grazing diets – an original concept that informed development of the VAF Feed Block.
In aquariums, grazing diets are strategically suspended in key locations to facilitate natural grazing behaviour and create observation opportunities. In aquaculture, this principle is applied as a means of dispersing the cleaner fish around the pen, maximising their exposure to sea lice. The water-stable blocks maintain integrity when in the water – so pieces do not crumble or break away without being bitten off. This method of presentation is targeted specifically at the natural feeding habits of cleaner fish. Unlike salmon, these demersal species feed by gravitating around the feed block and graze by taking small bites. The grooved texture of the block is explicitly designed to allow the distinct mouth parts of cleaner species to gain better purchase on the feed, providing optimum grazing potential. Salmon, being pelagic feeders, ignore the blocks, feeding in the mid-water column on food that appears in front of their faces.
World Feeds Managing Director, Peter Kersh, asserts “The fact there has never been a dedicated diet like the VAF Feed Block on the market is likely why there have been so many concerns surrounding cleaner fish welfare in the first place.” Studies and trials using the blocks have recorded stable, controlled growth rates, significantly reduced mortality and less aggression during feeding. All results indicative of a marked improvement to cleaner fish general health and welfare – in turn improving their efficacy as sea lice hunters.
World Feeds is now bolstering the effectiveness of the range by trialling the feed blocks at the hatchery stage. Several operations, including Ocean Matters and Otter Ferry, noted that this early-stage exposure helped to acclimate the fish to grazing on blocks, leading them to habitually gather at depth in selected locations for feeding. This behavioural practice becoming ingrained at the hatchery stage enables even greater effectiveness of VAF’s feeding strategies once the adult cleaner fish reach the sea pen.
Improving the way fish are fed