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Offshore in America
DESPITE regulatory issues, offshore fish farming is likely to play an ‘exciting’ part in the future development of American aquaculture, leading researchers in the States have said. Dr Richard Langan, director of the University of New Hampshire’s Open Ocean Aquaculture (OOA) project, said that with new cage and farm designs in development, this is a ‘very exciting time’ for offshore aquaculture.
However, Dr Langan said the industry will continue to be reluctant to invest in offshore aquaculture until a regulatory structure is introduced in the United States.
The OOA was established in 1998 to demonstrate the commercial potential for fish and shellfish culture in open water environments in the Gulf of Maine. In 2004, it harvested halibut grown in offshore cages and this year it has harvested offshore farmed cod and haddock for the first time.
An interdisciplinary approach means that while researchers have been testing the suitability of these species for offshore farming, engineers have been engaged in the design and development of offshore technology.
Speaking to Fish Farmer, Dr Langan said that of the three species trialled, halibut has shown the most potential as a commercially viable species, mainly due to its resistance to disease. Haddock has been problematic as the fish’s growth rate slows dramatically when it reaches sexual maturity, and cod has been difficult to harvest as the fish can’t adjust their swim bladders readily and are therefore susceptible to decompression problems.
‘We’re looking at several different strategies for halibut and are also looking at what the Norwegians are doing,’ Dr Langan said. ‘This fall we’re going to try stocking out a larger fish, one that’s nearly a kilogram, and we’re going to try growing it to a larger size of 5-6kg. The first time we bought fish that were 30g, put them out to the cages at 100g and grew them out to 4kg but that took three years. So we’re looking at getting them from a land based facility at a larger size and seeing if we can’t capture that faster growth rate.
Dr Langan said that while the duration of the growth period carries with it a tremendous amount of economic risk, halibut do very well in these conditions with few to no mortalities occurring during the last production cycle. In fact, there were few to no mortalities in any of the species raised, he said.
When it comes to fish escapes, the project has a clean record, a factor Dr Langan attributes to careful handling during transfers and offshore-specific engineering. New cage designs are currently being trialled, including a 5,000 cubic metre geodesic dome-shaped cage, a scaled down prototype of which was launched recently. Load cells will be fitted to the lines that attach the cage to the mooring system in a bid to understand more fully the
motion of the cage and the stress and strain placed upon it. This will help determine the most suitable type of materials and mooring system for use in a full-scale version.
The project has also been focusing on improving automation and communication, and advancements in wireless technology have resulted in higher quality video feeds.
‘One of the keys to successful offshore farming is being able to communicate and being able to see what’s going on underwater from shore because sometimes you just can’t get out there to see what’s happening,’ Dr Langan said.
The project aims to help develop ‘clean and sustainable’ fish farming in the deep ocean. Implicit in this is the importance of creating an operation that weighs lightly on the environment, and provides a humane habitat for fish. While researchers say the project has so far had no measurable environmental impact – a factor they put down to the high energy environment of the Gulf of Maine where prevailing currents move huge volumes of water through the fish cages on a regular basis – it is difficult to predict the environmental impact of a commercial size farm. However, researchers will continue watching the environment very carefully as they scale up the operation to raise commercial-size populations of fish.
‘We’re certainly recognising that, in order for aquaculture to be successful, it’s got to be compatible with the goals in this country for integrated coastal management, and what is referred to as ecosystem based management,’ Dr Langan said.
This includes understanding how well aquaculture fits in with other activities such as fisheries, navigation and energy development in offshore areas.
The researchers want to ensure that offshore aquaculture is environmentally sustainable. With this in mind they are looking at issues such as the long-term supply of protein to feed fish. Alternatives are being considered, such as the use of marine invertebrates rather than fishmeal to provide this protein. Energy issues, such as ways to power the farms, are also being considered.
‘It’s a ten-year schedule to look at some of these possibilities,’ said Dr Langan. ‘Not that someone couldn’t start farming fish right now and be economically viable but I think in the long-term we have to be looking at all of these issues to say what the farm of the future is going to be like. There are some very interesting new cage and farm designs coming around so I think it’s a very exciting time for offshore aquaculture.’
Dr Langan does have some concerns about the future development of the sector. The introduction of the National Offshore Aquaculture Act is set to give the National Oceanic and Atmospheric Administration the authority to license fish farms in almost 4.5 million square miles of federal waters. This act was introduced to Congress in June and amendments have been offered but it has yet to be put to serious debate.
‘I’m hoping that they deal with it in this congressional session,’ said Dr Langan. ‘The stability of a regulatory structure is really needed before we’re going to see some investment. If there’s uncertainty in how long their tenures would be in a particular situation and what the fees they would be paying for leasing space would be, then you’re going to find a tremendous amount of reluctance on the part of the industry to invest.’
Despite these concerns, Dr Langan remains optimistic that offshore fish farming offers a way forward for aquaculture.
‘I think it is part of the future for aquaculture. I think we have lots of other opportunities, perhaps not in finfish culture but in shellfish culture in the near shore environments. We certainly have not reached the potential for that.’
Dr Langan said he believes an opportunity also exists for cultivation of seaweeds and sea vegetables. He said this has yet to be explored, mainly due to low consumption rates of seaweeds in the US.
‘There are also export markets and the US certainly has a trade imbalance that it could start offsetting with some exports,’ he concluded.