Mariculture's Brave New World


Natural selection evolved to selective breeding leading to biofortification only to be trumped with genetic engineering for advancing the Blue Revolution.  A sequenced genome could produce better management of fish stocks and greater understanding of pathogens and resistance to disease, leading to increases in growth, reproduction, feed-conversion efficiency, and oxygen and temperature tolerance.  The Atlantic cod genome has been sequenced by a Norwegian consortium and the Atlantic salmon, with a genome three times the size, will be made public next year along with the catfish genome.  

Monsanto has genetically modified (GM) soybeans to produce oil containing omega-3 fatty acids.  One year ago, the FDA ruled that GM soybeans are safe; thus, easing pressure on fish stocks which hitherto have been the principal source of omega-3 fatty acids.  The positive potential of GM laboratories creating plant mutants for feeding humanity also applies to fish.   AquaBounty Technologies recently dominated the media with FDA approval of their GM salmon to enter the food supply.   Upon injecting genes from two other species they got their “frankenfish” to grow to market size of about 8 pounds in just 18 months that is half the industry standard of 36 months.  

Consider the potential if GM cobia, the “Tropical Salmon”, could be harvested in 6 months?  Aquatic animals’ ability to spawn millions of progeny as compared to terrestrial animals’ litter of at most a dozen is destined for fast-track genetic exploitation.  This promises exponential advances for feeding the future masses in a “Brave New World” of mariculture. 

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.”

Oyster & Shrimp Symbiosis


A major problem with fish farming is water pollution.  Fish waste, uneaten feed and fecal matter accumulate in the aquatic environment affecting the farm and neighboring water supplies.  It is estimated that up to a ton of waste is produced for each ton of fish raised.  Most of the waste is in the form of organic solids and inorganic nutrients such as nitrogen and phosphorus causing “over-nitrification” and the spread of algal “blooms” – massive blankets of green slime on the water’s surface that precipitate bacteria growth, deplete oxygen, and kill much of the life in the water below.  

In 2001, shrimp surpassed canned tuna as America’s favorite seafood.  Today, more than one billion pounds of shrimp are imported from foreign farms.  While shrimp is now the most popular and widely traded seafood in the world, its rise in popularity and profitability is shadowed by its environmental costs.  A solution, Integrated Multi-Trophic Aquaculture (IMTA), is a practice in which the by-products (wastes) from one species are recycled to become inputs (fertilizers, food) for another.  For example, shrimp farming is combined with shellfish and seaweed farming to create balanced systems for environmental sustainability.  

Scientists from Canada have been growing mussels and kelps adjacent to salmon cages in the Bay of Fundy since 2001 and are documenting its IMTA data.  The rigorously examined mussels are free of contamination and of any “fishy” taint from neighboring salmon.  Moreover, this nutrient abundance is having a positive impact on the growth of both species: the mussels reach market size 8-10 months earlier than normal and the kelps grow greater by 46%.  Hopefully, this economically attractive and ecologically sustainable concept will be adopted globally.  Consider: Expanded research and collaboration by scientists across the globe employing next generation Internet technologies for researching the efficiencies of other native shellfish filter feeders and kelp species for IMTA in developing countries.


Hybrid Vigor?


The term heterosis, also known as “hybrid vigor “, describes the increased strength of different characteristics in hybrids: the possibility to obtain a genetically superior offspring by combining the virtues of its parents.  Oysters possess this unique and remarkable property resulting in offspring growing twice as fast and large as their parents.  Seed companies exploited this phenomenon to increase corn yields seven-fold from the 1920s spawning the Green Revolution.   This genetic characteristic is now being exploited for oyster breeding and farming if the Blue Revolution is to feed another 2 billion people on the planet by 2050.  I recently visited the Wrigley Institute for Environmental Studies Campus on Catalina Island and was amazed to learn that they are breeding oysters to grow twice as fast as their wild ancestors.  Hundreds of millions of baby oysters have been bred and are now maturing at Taylor Shellfish Farms located on the bays and inlets of Washington’s Puget Sound awaiting harvest of 5-8 million in 2011.