E! 6923 Preserved zooplankton as a diet for marine aquaculture species (MARAQUAFEED)

In marine larviculture, the highest success factor is to offer the fish larvae a diet of high and appropriate nutritional quality. Live feeds are commonly used at hatcheries today, but it is not possible to copy the nutritional status of the natural prey for fish larvae, which are marine copepods. Planktonic is harvesting marine copepods from natural waters and has managed to preserve the nutritional quality of the copepods as if they were fresh. Results so far in the project display an improved stress-tolerance of fish larvae when offered the Planktonic diet. The main challenge is to keep the preserved copepods suspended for a long enough time to be grazed upon by the fish larvae, and this is identified as our biggest challenge in the project. The water dynamics in the fish tank is of high relevance for keeping our particles suspended, and an appropriate water current system in the tank results often in increased feeding incidences of the fish larvae. In the experimental trials where high appetite has been observed (probably as a cause of appropriate water dynamics in the fish tank), the performances of the fish larvae has always been very positive (increased growth, survival and stress-tolerance) compared to the control of 100% live enriched rotifers and Artemia nauplii. One of the work packages in the Maraquafeed project that has a focus of an improved water circulation that potentially can increase the time our particles can stay suspended in the water column display so far very promising results. The methods for improved water circulation has until now not been implemented in fish start feeding trials. Experimental studies of how to include our raw material of copepods into a formulated dry feed particle has shown promising results. Some technical challenges have been experienced to include our raw material, but seem now to be solved. A major breakthrough has occurred in 2014 and 2015, and we have developed a new preservation method that has contributed to increased appetite from fish larvae, and in addition, the particles are kept for a longer period in the upper water column before sedimentation. Several trials in in a commercial aquaculture plant that produces ballan wrasse has resulted in 100% higher growth compared to the control, and also a considerable decrease in mortality. In commercial trials with lump fish larvae also very good results have been obtained. The good results will probably initiate sales within the cleaner fish segment.

In the marine aquaculture industry, first feeding of early stages of fish are characterized by high mortality, deformations and sub-optimal growth which limit the overall production. One of the major reasons is inadequate nutritional value of live feed or ganisms and commercial diets, and low feeding incidence of weaning diets. Feeding trials with fish larvae using the diet from Planktonic documents up to 100 % higher growth and survival, 3.5 times higher stress-tolerance and 50 % reduction in mal-pigment ation compared to standard live feed diets. This projects primary objective is to establish a feeding protocol for optimal use of the novel diet at marine hatcheries, and involves well established and more challenging marine aquaculture species. Plankto nic has methods for harvesting and preserving the natural diet most marine larval species is evolutionary adapted to, which are marine planktonic copepods (marine zooplankton). The patent pending method involved, ensure the original nutrient profile of co pepods. Copepods represent a huge bio-resource and display the highest biomass of metazoans on earth. Following the live feed period, the marine larvae are weaned onto dry feed. The novel diet is different than other microdiets, which applies to charact eristics such as high nutritional quality, low leakage of nutrients and low sinking velocity. The new diet is a soft feed in comparison to competing products that normally is dry. This is advantageous because it might not dehydrate parts of the sensitive gut of the marine larvae. If the project does succeed, it will lead to a giant step for the aquaculture industry, because the bottle-neck of first feeding will be solved, and the production potential of the marine species can be fully exploited.