Open Ocean Mariculture for Developing Nations


Seafood today is following the ancient course of land animal domestication that evolved from food foraging occurring some 10,000 years ago.  In the past 50 years the global seafood market has transformed whereby about half the fish and shellfish now consumed are farmed. This deliberate farming of ocean species is the fastest growing form of food production in the world amounting to $50 billion and is recognized as the Blue Revolution. This can be equated to the earlier “Green Revolution” between 1965 and 1970 when wheat yields nearly doubled. Globally, wild fisheries have reached or exceeded their maximum sustainable harvest.

Mariculture, the cultivation of marine organisms in their natural habitats for commercial purposes has the potential to revive the natural majesty and abundance of the oceans.70 percent of the Earth is covered with ocean, which could be developed into sea farms. Coincidentally, 70 percent of the world’s total fish catch comes from developing countries. These fisheries are collapsing which will be catastrophic for the 22-24 million-dependent fisher folk and the 68-70 million people who work the marine post harvest in developing countries.  With 90-95 percent of the catch destined for domestic markets, this seafood supply crisis promises profound and dire consequences.  Wild caught fish provide one of the few options for eating animal protein for the denizens of developing countries.  In Africa, 200 million people obtain between 22 and 70 percent of their dietary animal protein from fish, while in most other developing countries the average is 13%.  Add to this the vital role of fish in providing the poor with micronutrients and essential fatty acids, and the importance of sustaining fish stocks as a source of food and nutrition for the poor rivals other global epidemics.

Malnutrition causes more deaths than AIDS, tuberculosis and malaria combined.Simply maintaining current per capita consumption will require 1.6 million tons more fish every year by 2015, increasing to 4.2 million tons by 2030.  This mandates not only sustaining the fisheries that these poor consumers depend upon, but also for creating economic incentives to encourage the transfer of technologies that will allow mariculture enterprises to flourish in developing nations and do so in ways that are environmentally sustainable.  The Consultative Group on International Agricultural Research (CGIAR) estimates that an investment of US $30 million in technology development, transfer, and capacity building for mariculture, combined with improvements in policy and markets access, can produce 3 million tons of fish by 2020, and generate up to US $2 billion annually.  

A new technology paradigm for farming the seas is emerging which promises a solution to global food shortages and looming fresh water crisis. Offshore cultivation of marine species, finfish, shellfish, shrimp, and seaweed are being developed that employ environmentally sustainable techniques and technologies. “Open Ocean” marine farming operations for finfish and shrimp are conducted in cages and with shellfish on long-lines deployed in deep, pristine waters in tropical seas having optimum currents.  This offshore marine farming concept reduces reliance on wild fishery resources while softening any environmental footprint because the seas are so vast.  A diversity of Open Ocean crops provide a comprehensive nutrition menu: Cobia, the “tropical salmon” uniquely store fat and oils in their flesh and have one of the highest levels of healthy omega-3’s. 

Oysters, the “soybeans of the sea” pack huge amounts of protein, are loaded with vitamins and omega-3 fatty acids and replete with minerals: calcium, iodine, iron, potassium, copper, sodium, zinc, phosphorus, manganese and sulfur. Shrimp is an excellent source of protein, selenium, vitamin B12, iron, phosphorus, niacin, and zinc.  Seaweed provides a balanced diet and possesses nutrients and trace elements not available in land plants.  There are advantages to farming in offshore waters:  The swift currents supply ample food to promote faster growing shellfish and submerged long-lines are not as vulnerable to damage from typhoons and cyclones that are prevalent in tropical regions.  Open Ocean shellfish and seaweed farming also have a number of advantages for developing nations.

✦ Simple technology using locally available materials

✦ Labor-intensive operations.

✦ Low capital investment.

✦ Minimum environmental impact.

✦ Cultivation contributes to food security and national nutrition.

Moreover, shellfish and seaweed don’t require feeding but consume and cleanse native nutrients from the sea. Anchored in approximately 100 feet of water and suspended 30 feet below the surface, 500-foot buoyant long-lines hold hundreds of biodegradable “socks” filled with mussel seed.  Mussels have a relatively rapid grow-out period, reaching harvestable size within 10 months and each long-line has the potential to produce about 10,000 pounds of mussels per year.  

Oysters can also be cultured in nets hung on submersible long-lines and will be planted in nets at about ¼ inch in size and grow to about 3-6 inches in one year when they can be harvested.  Each oyster long-line can produce about 50,000 oysters. 

Coastal shrimp fisheries in most developing nations are struggling to cope with collapsing shrimp stocks and record-low prices.  Large trawlers offshore compete with artisanal fishing in bays and estuaries, further depleting the resource base, engendering poverty and spurring conflict.  Land-based shrimp farming only exacerbates the situation through additional disputes over land use and water contamination from toxic effluents.  Additionally, land-based shrimp farming results in degradation of coastal habitats.  Unlike conventional shrimp capture and farming methods,  Open Ocean shrimp farming in cages features the following benefits: no by catch; no destruction of mangroves or impact on benthic ecosystems; no use of antibiotics, herbicides or pesticides; low food conversion and feed fish equivalency ratios; low levels of detectable waste; low energy use and carbon emissions; and a high level of resilience to climate change. “With Earth’s burgeoning human populations to feed, we must turn to the sea with new understanding and new technology,” Cousteau said in his 1973 television show “The Undersea World of Jacques Cousteau.” “We need to farm it as we farm the land.”