The most advanced projects in offshore mariculture
As the global population is expected to reach 9 billion by 2050, demand for food and feed will substantially increase, and meeting the demand of the world’s growing population is becoming a major challenge. Inland aquaculture may be a better alternative but it could involve clearing more rainforest and draining more aquifers or using more fertilizers and pesticides as agriculture spreads to marginal lands. For these reasons, offshore mariculture offers significant potential for increasing world food production in an environmentally sustainable way without compromising land use. Offshore mariculture may help mitigate some of the negative consequences associated with more near-shore and land-based farms. Less freshwater need, greater distance, and depth from shore, and/or faster currents could help reduce impacts such as pollution, disease occurrence, and area use conflicts. While they may not be as numerous as land-based operations, offshore fish farms are leading the charge when it comes to advanced mariculture technology, technique, and design.
One of the advanced mariculture technology already underway neutralizing some of the problems associated with near-shore fish farming is Aquapod. Invented by Ocean Farm Technologies – which has since merged with OceanSpar to create InnovaSea Systems – these Aquapod cages were inputted into Earth Ocean Farms’ operations back in 2011. They are constructed with a series of triangle net panels fashioned into a sphere. The geodesic sphere form of Aquapods holds a maximum amount of volume with a minimum amount of surface area, giving them a better chance at surviving the harsh weather and storms that can occur offshore. A dive team and biologists monitor the cages, which are suited for open ocean conditions and a diversity of species. Several Aquapods are already being tested and researched in La Paz, Mexico where a single installation can raise nearly 100,000 large ocean food fish.
Another InnovaSea Systems technology is SeaStation, which is a fully submersible pen with a volume that ranges from 6,400m3 to 14,500m3. The system uses a central spar to provide buoyancy. This is fully adjustable, so the pen can be lowered or lifted as needed. A central rim provides stability, specifically for when the system is surfaced. These pens are ideally installed in water of 60m to 100m depth. The system is normally kept fully submerged and is ideally suited to deployment in areas with year-round strong wave activity and storms. Fish can be bathed using a tarpaulin system, but the pen seems initially more difficult to work with and pricier compared to standard floating cages. However, the company argues that its enhanced efficiency should, over time, reduce repair and manpower requirements. Moreover, they point out that their SeaStations have survived numerous Category 3 and 4 hurricanes and typhoons over the last two decades and are engineered and constructed to handle the daily pounding of relentless choppy seas, the kind of wear and tear that over time will destroy a traditional surface pen.
The company’s latest offering is the Evolution Pen, which is a floating system that can sink using a pendant weight system when needed. This system is available in several models, ranging from one with an 8m net depth with a volume of 2,860m3 up to a version with a net depth of 20m and a volume of 22,390m3. The buoyancy of the system is fixed using foam padding in the piping, with variable buoyancy regulated through pressurized air in a floodable chamber. Floating cages are generally easier to work with and, in areas where large storms only occur sporadically, the company suggests that the Evolution Pen is probably a better alternative.
Besides these innovative pen designs, the company has also developed a new approach to netting which is a brass netting product that better protects cultured fish from large predators like sharks and dolphins. These copper-alloy nets also help against biofouling and the nets no longer need to be changed regularly, as they stay free from algae and barnacles. A third unexpected advantage is the dramatic reduction of external parasites when using these nets material. Brass netting creates a much cleaner and healthier environment for fish to grow in, and Innovasea wanted to independently confirm its viability by conducting a study on the concentration of dissolved copper level around the fish farm nets. The study revealed that dissolved copper levels at two fish farms stayed below 1 microgram per liter at all times, which is lower than the standard water quality parameter for copper.
With the integration of Realtime Aquaculture and HTI-Vemco into Innovasea, the company is also gaining traction in the development of digital farm management and monitoring systems that are based on Artificial Intelligence (AI). This offers significant potential for improvement, as farm monitoring and management are still mostly based on human instinct and gut feeling. Feeding, for example, constitutes the largest operational cost in the farming of finfish, and Innovasea has developed a monitoring system consisting of cameras in and below its pens. The system uses AI to track both the feeding behavior of cultured fish and to track excess pellets, which pass through the nets on their way to the seafloor, greatly reducing and potentially eliminating excess feeding and wastage. As part of overall monitoring, the company has also developed a self-learning algorithm that can analyze incoming video streams to calculate standing stock and the overall biomass in a pen, thereby improving feeding and treatment regimens, as well as farmers’ production projections. The system is species-specific and needs about six months to properly familiarize itself with a new species. It is already fully functional for cobia, kingfish, snapper, and salmon.
These technologies are no doubt pricy, as well as having extremely strict selection procedures to ensure project compliance with environmental and social responsibility. Despite that, initializing modern and advanced tools for fish farming will present a host of opportunities – particularly for farmers focusing on high-value species such as bluefin tuna or kingfish. With sustainability becoming a top priority in western supply chains and with offshore aquaculture operations finally starting to take off, we are bound to hear more from the exciting company in the near future.