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Presentation of EcoFish

Published by CLR on 2009/10/3 (45613 reads)

Ecofish is an exciting international project to promote the commercial rearing of ballan wrasse, Labrus bergylta and to develop methods for the successful use of ballan in salmon and cod cages to control sea lice. The project involves partners in Norway, Scotland and Ireland and is supported by the EU programme called the Northern Periphery Programme, Nordland Fylkeskommune (Norway), Highlands and Islands Enterprises Ltd. (Scotland) and the Fish Farming member associations, Bord Iascaigh Mhara (Ireland). Fulfilling the projects objectives, the projects intension is in line with the NPP's statement "Innovatively investing in Europe’s Northern Periphery for a sustainable and prosperous future”.

The strategic partnership includes participants from the private sector such as Daithi O'Muruchu Marine Research Station (Ireland) and associated private partners; Fjord Research Station Ltd, (Norway) Kvarøy Fish Farm Ltd (Norway) the Ardtoe Marine Laboratory (Scotland), Lighthouse Caledonia and, the Scottish Salmon Producers' Organisation. The university sectors are represented by the Faculty of Aquaculture and Bioscience, Bodø University College (Norway) and National University of Ireland, Martin Ryan Institute (Ireland) and the Norwegian Institute for Agriculture and Environmental Research -Bioforsk- (Norway).

The rapid expansion of finfish farming in Northern Europe has focussed attention on problems caused by a variety of pest organisms and one of the most serious of these is sea lice (Caligidae), both Lepeophtheirus salmonis and Caligus elongatus.
Originally lice were treated with organophosphate pesticides and more recently with hydrogen peroxide, but these are no longer used, leaving only one effective treatment, emamectin benzoate (SLICE, Schering Plough). However, there is growing concern that lice are becoming resistant to this last effective treatment, so an alternative method of controlling the parasite is urgently needed. One solution that has been tried in recent years is biological control through the use of wrasse which can clean the lice off salmon, thus avoiding the need for any medicinal treatments.
Experiences from Norway, Scotland, and Ireland indicate that the use of wrasse is effective in controlling sea lice infestation in larger salmon. The number of lice in trials with salmon of 3 to 7 kg were reduced from 60 to 1 per fish over 4 weeks. These data were obtained by lice counts and stomach analyses. Nevertheless, different sizes and species of wrasse are used at different times of the salmon farming production cycle. Therefore good husbandry and welfare issues of wrasse in salmon pens have to be defined and promoted.
Whilst this is ostensibly an ideal solution to the problem, a large number of wrasse is required by the salmon farming industry. In contrast, there have been reservations from environmentalists about fishing the wrasse from wild stocks with possible erosion of local stocks and changes in population structure, whilst farmers and regulators remain concerned about other diseases being transferred from the wild wrasse to the salmon. Finally, there has been no report of rearing success in a commercial scale with ballan wrasse even though other species of wrasse, such as corkwing and goldsinny, have been reared previously. Ballan wrasse has been selected in this study because it has been shown to be a successful cleaner of sea lice in preliminary trials and could be more suitable than smaller wrasse with larger salmon in their second year of production.

The organic farmed salmon and cod market has been identified as an important niche for the industry and the use of medicated treated feed for the control of sea lice may not be acceptable in the future to achieve organic certification. Thus, a cost-effective and sustainable solution to sea lice infection is clearly an urgent priority for the aquaculture industry. Following recent initiatives by farms and some organic certification bodies, the use of Ballan wrasse is becoming of increasing interest. This ecologically friendly approach will also add value to the final product and therefore will command a higher price, particularly if organic status is also achieved. It should also be noted that cod aquaculture is expanding but the use of cleaner fish to remove lice form cod has not been previously examined.

The objectives of the project
This project has the objective of providing the marine finfish aquaculture industry in Europe with a practical solution to control lice in an environmentally friendly way by using ballan wrasse (a lice eating fish) as part of an integrated approach to control lice in sea cages.
This project seeks to resolve all of the above issues by developing the technology for spawning and rearing the most promising cleaner fish, ballan wrasse. This will allow large numbers of disease free fish to be produced both economically and sustainably. It will also examine the management of wrasse in salmon cages to achieve the effective removal of lice whilst at the same time safeguarding the health and welfare of the wrasse themselves.
The project intends to develop the methods and technology required to rear cleaner fish for use by the cod and salmon farming industry in the partner countries. The physical outcome of the project will be a substantial number of wrasse for field application for farm testing the technique on cod and salmon farms in partner countries. Dedicated marine hatchery areas to rear wrasse will be established in Ireland, Norway and in Scotland with the focus on developing successful rearing techniques and production through close collaboration and exchange of information. The part of the project to examine the management of wrasse in salmon and cod cages will focus on the welfare of the wrasse.

The work objectives of the project are:
• Establishment of productive broodstock (parent) ballan wrasse in regional hatcheries.
• Determination of broodstock management practices for optimal egg production
• Establishment of a constant and reliable supply of wrasse eggs for larval rearing
• Establishment of protocols for optimum survival and growth of wrasse larvae
• Development of procedures for rearing wrasse in the hatchery to ensure maximum survival and rapid growth to enable wrasse to be stocked in a short period
• Stocking density of wrasse used to control sea lice in salmon will be recommended
• Give recommendations to the salmon farming industry on proven lice control systems using wrasse

First results from the project
In Scotland Ballan wrasse as broodstock for the project were sourced from the wild fishery and were captured locally and some were also obtained from fishermen. No diseases were detected following 3 months of fish being held in quarantine. Three tanks of broodstock were established under ambient light and thermal conditions and later one of these stocks was transferred to a delayed photoperiod regime to provide out of season eggs. Wrasse were successfully domesticated and a variety of diets was examined. Sex determination of the fish has been difficult and obtaining breeding males in particular. A trial was carried out using different spawning substrates. A batch of 9000 ballan wrasse eggs was collected by scraping the eggs from pipes in a tank. The eggs were incubated in 10 litre tanks with water supplied at 200 mls per minute and mild aeration. The development of larvae was investigated and larval rearing regimes including live feeding were developed.
In Ireland the acquisition, maintenance and treatment of potential broodstocks is described and the findings of a long-term trial to establish standard and out-of-season spawning groups are reported. An allied experiment, examining compensatory feeding behaviour in undernourished adult fish as compared to healthy stocks, similarly, gave positive initial results with significantly higher feeding levels being reported for the undernourished fish. A large number of wild fish of several year classes has been captured in autumn 2008 and a significant experiment to determine feeding behaviour of juvenile fish is being embarked on at present while groups of potential broodstock fish have been established for breeding in the 2009 season.
In Norway Ballan wrasse broodstock were caught in the southern part of country. The capture operation for wild fish, transport and stocking of broodstock tanks had to be repeated three times, because of outbreak of the disease furunculosis and subsequent mortality. In the third transport all fish were vaccinated against atypical furunculosis before transport. There was no mortality in this group during transport, or during culture in the following months, thus it was concluded that the vaccine was very effective. Initially different feed for the broodstock were tested. Commercial pelleted feed were not very attractive, whereas a mixture of shrimps and a commercial feed mixture for marine fish were found be the most attractive feed. Spawning behaviour and spawned eggs were not observed in any of the broodstock tanks. A production and experimental set-up is being established for trials and production of ballan wrasse larvae. These facilities include new equipment, including a reactor for rotifer production, and rooms for live feed such as rotifers, Artemia and algae.
The expertise obtained during the first year of EcoFish in broodstock establishment and management, hatchery technology and startfeeding is a good basis for progress and are important first steps in producing a manual of Ballan wrasse juvenile production, and thereby a contribution to an sustainable and eco-friendly production of salmon using reared cleaner fish.
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