The Problem Is Caused by Rapid Intensification
Industrial-scale fish farms have begun popping up all over the world, with aquaculture expanding about 14x since 1980. In 2012, the global output reached over 70 million tons, exceeding beef production for the first time. Population growth, income growth, and seafood’s healthy reputation are expected to continue driving demand by 35% or more in the next 20 years. The new ‘blue revolution’ has delivered many benefits to farmers, distributors, and consumers across the globe. However, like any other kind of farming, fish farming has begun taking a negative toll on the environment and farmers are searching for ways around it.
Aquaculture pollution which typically consists of nitrogen, phosphorus, and dead fish, has become a widespread hazard in Asia as the region accounts for over 90% of fish farms. As fish are overcrowded into small pens, some farmers have even resorted to using pesticides and antibiotics that are banned for use in the U.S. to keep the fish alive. Fish farms in other parts of the world have also seen similar problems, with parasites and diseases causing outbreaks on farms around the globe.
The problem isn’t the industry of aquaculture so much as its the rapid intensification of it. Chinese farmers began raising carp in farms on their rice fields over 2’000 years ago, but the country’s production has grown to 42 million tonnes per year. Fish pens are now common in China to line most rivers, lakes, and seashores, and farmers fill their farms with fast-growing breeds and maximize growth with concentrated fish feed. The trick lies in finding a way to do that without spreading disease and pollution.
One fish farmer, Bill Martin, believes that land-based farms are the solution. He keeps his fish tanks on land as opposed to maintaining nets in a lake or sea to offset the likelihood of developing sea lice and disease. According to Martin, keeping the fish in a controlled environment allows zero ocean impact. However, it does still have similar effects on land and air pollution, and it’s quite expensive to run. Another farmer, Brian O’Hanlon, went the opposite route. He believes that keeping the pens deep below the ocean surface where the fish have plenty of room to roam diminishes the negative effects.
The Solution Might Have More to Do With What We Feed The Fish Then Where We Farm Them
To learn more about the environmental impact of aquaculture and the innovations that farmers are creating to reduce pollution, go to NationalGeographic.com:
“Figuring out what to feed farmed fish may ultimately be more important for the planet than the question of where to farm them. ‘The whole concept of moving into offshore waters and on land isn’t because we’ve run out of space in the coastal zone,’ says Stephen Cross of the University of Victoria in British Columbia, who was an environmental consultant to the aquaculture industry for decades.
In a fjord on the British Columbia coast, Cross has devised a polyculture of his own. He feeds only one species—a sleek, hardy native of the North Pacific known as sablefish or black cod. Slightly down current from their pens he has placed hanging baskets full of native cockles, oysters, and scallops as well as mussels that feed on the fine organic excretions of the fish. Next to the baskets he grows long lines of sugar kelp, used in soups and sushi and also to produce bioethanol; these aquatic plants filter the water even further, converting nearly all the remaining nitrates and phosphorus to plant tissue. On the seafloor, 80 feet below the fish pens, sea cucumbers—considered delicacies in China and Japan—vacuum up heavier organic waste that the other species miss. Minus the sablefish, Cross says, his system could be fitted onto existing fish farms to serve as a giant water filter that would produce extra food and profit.
‘Nobody gets into farmed production without wanting to make a buck,’ he adds, over a plate of pan-seared sablefish and scallops the size of biscuits. ‘But you can’t just go volume, volume, volume. We’re going quality, diversity, and sustainability."
What are some sustainable practices you have seen from aquaculture farms recently?
Source: How to Farm a Better Fish - National Geographic
Photo Source: WIX - www.wix.com
Written by AQUAMERGE
March 23, 2023