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Fish Farming a Bust

By Various Authors. Posted to reef-l emailing list, Friday the 30th of June to Monday 3rd July 2000.

Glenn R

Just got this on my local diving list, thought it may be of interest...

Study Fish Farming a Bust
Growing Seafood Doesn't Relieve Pressure
By Rick Callahan
The Associated Press

June 28 — Commercial fish farms have long been touted as a way to boost the global seafood harvest while taking the pressure off Earth's overtaxed oceans. But it hasn't worked out that way, researchers say. They conclude that aquaculture — the production of everything from catfish to shrimp — has instead raised demand for some ocean fish such as anchovies that are ground into fish meal to fatten their domesticated cousins. What's more, the researchers say, fish farming has created vast amounts of animal waste that has fouled coastal areas where fish and shellfish are being raised. In addition, they say, domesticated fish such as salmon have escaped from offshore holding cages where they are grown, displacing their smaller, wild relatives.

One in Three is Farmed
"There's a perception that farmed fish completely relieve the pressure on the oceans. But people have completely missed the connection, that it really is very reliant on the oceans and is having a big impact on them," said Rosamond L. Naylor, a senior fellow at the Institute for International Studies at Stanford University. Naylor led a study published in Thursday's issue of the journal Nature. The researchers, from Sweden, Britain and the Philippines, included members of the World Wildlife Fund and the Environmental Defense Fund. Commercial fish farms produce about one of every three fish humans eat.

Aquaculture experts said the paper raises valid concerns they have been trying to address for years. Still, they said it overlooks research advances and management changes already helping the industry reduce its environmental impact. "As with any new industry, there are some growing pains, and we believe we're getting on top of those," said Chris Kohler, director of the Fisheries and Illinois Aquaculture Center at Southern Illinois University in Carbondale, Ill.

Vegetarian Diet
Paul Brown, a professor of aquaculture at Purdue University, said he and other researchers have developed diets without fish meal for rainbow trout and are working on vegetable-based diets for hybrid striped bass and yellow perch. "If we're going to get to the huge numbers that are expected for aquaculture development, we simply don't have enough fish meal on the planet to do it," Brown said. Other feeds in development could reduce the amount of waste produced by farmed fish, he said. Over the past 25 years, aquaculture has experienced tremendous growth and, in 1997, nearly 30 million metric tons of fish were produced — twice the 1990 harvest, said Edwin Rhodes, aquaculture coordinator for the National Marine Fisheries Service.

Study says aquaculture practices harm worldwide fish populations
6/29/2000 — Fish farming may be helping to deplete worldwide fish populations in some cases, according to a new report evaluating the impact of aquaculture worldwide. The study, penned by a 10-member group of ecologists, economists, fisheries and aquaculture specialists, evaluated whether farmed fish are adding to global food supplies or contributing to the depletion of fish stocks worldwide.

According to the study, fish farming on balance is still adding to the world's fish supply. But, it states, many types of aquaculture are accelerating a move towards a worldwide fisheries collapse.

Among the practices that the study says contribute to that acceleration is feeding wild caught fish to farmed fish. According to the study, many farmed fish are fed ground up wild fish; it takes 3 pounds of wild caught fish to grow a pound of shrimp or salmon. Farms are also increasingly feeding vegetarian species fish oil and fish meal to enhance production.

Some aquaculture operations produce waste laden with fish feces, antibiotics and uneaten feed. Untreated effluent contributes to pollution of coastal waters, the study says.

The destruction of hundreds of thousands of hectacres of coastal wetlands and mangroves for aquaculture also harms critical habitat for wild fish, according to the study.

The report also recommends several ways aquaculture operations can reverse these trends and farm fish in an environmentally sustainable manner.

Mike Kirda

There are a number of reasons that aquaculture does not live up to its potential. The article has some valid concerns, and I know that a lot of the industry is taking these seriously. One of the major issues in the salmon farming industry, besides released Atlantic salmon in the Pacific NW, is the fact that they just don't taste as good as wild salmon. It's that varied diet...

However, once you get some of the cichlids, like tilapia, they eat anything, and the taste can be controlled by feeding a strict diet before harvesting. Great fish for aquaculture. I think many shrimp do well as well, even in earthen ponds. Taste hasn't been so much an issue...

Given that most ocean fisheries are near collapse, aquaculture is really the last hope. Let's hope that they get their act together before they get regulated out of existance, thereby putting further pressure on the ocean.

Eric Borneman

I have a friend who asked me about the benefits of shrimp aquaculture not too long ago. I summarized by saying, nice concept, but that coastal areas are cleared, mangroves lost, buffers lost, and huge amounts of concentrated waste released, etc. However, I also mentioned this - that if you go to Home Depot or a garen center, one of the best fertilizers is fish waste based fertilizers. I use it on some of my tropicals - the Plumeria and the Banastereopsis particularly like it. So, if these facilities could contain the waste, perhaps they would have another product to sell and increase their profits without damaging the coastal areas or they could use the waste to fertilize a substitute buffer - like maybe a ring of papaya trees around the aquaculture ponds? -, and then have another "product" to sell....

So many little impetus. Is money's alter-ego Beelzibub?

Scott Crumpton

So, if these facilities could contain the waste, perhaps they would have another product to sell and increase their profits without damaging the coastal areas

Awesome vertical market! They could learn something from the older ag industries.

Something else which might be missed is the availability of fish meal from the fish guts, carcasses, etc from processing plants. Surely this isn't in low supply. The cattle industry makes wide use of meat and bone meal in feeding. Canibalism? Yes. Recycled waste? Yes.

So many little impetus.

Usually lack of knowledge, regulatory procedures or capital.

Is money's alter-ego Beelzibub?

Not likely, but the love of it is ;-)

Keith Redfield

Something else which might be missed is the availability of fish meal from the fish guts, carcasses, etc from processing plants. Surely this isn't in low supply. The cattle industry makes wide use of meat and bone meal in feeding. Canibalism? Yes. Recycled waste? Yes.

When I was a kid we got our Thanksgiving turkeys from the local trout farm. It was a neat co-generation facility where the trout were fed turkey guts, and the turkey got trout-enriched grain. And no waterways were impacted since this farm was in the middle of the Mojave desert ^)

p.s it's now a bunch of Condominiums where, I suppose, they farm people...

Mike Kirda

Not to beat the point to death, one of the more heartening aquaculture success stories is the Tilapia. This is a cichlid that can be grown in both fresh and salt water. One of the systems decribed on the aquaculture list allows one to do exactly what you describe- they essentially have a hydroponics setup suspended over the tilapia raceways. This limits the temperature and gives the farmer a second crop. Apparently they have great success with tomato plants, as they can be chopped up and fed to the tilapia after they stop producing fruit. They also can produce and harvest a large amount of seaweed, which is in turn used for fertilizer. They each just about anything, and apparently the taste of the fish can be modified by changing its diet for two weeks before harvesting. The ones I have eaten taste very good.

I really think it depends on the methods used and the species cultured.

Todd Crail

This is interesting

The tilapia I think you're refering to which are a redish looking fish from Africa, along with the largemouth bass and various crayfish are attributed to complete wild extirpation of the desert pupfish (Cyprinodon macularius) and a couple other local, "unique pool" pupfish upon their "accidental" introduction. Bucket biology is what it came down to really...

So I guess human interaction in the name of aquaculture really only gives a picture from who you're talking with at that moment.. ) I think the aquafarming is another evil, but am I asking how the salmon was raised when I buy my steaks for the grill? Who would know to tell anyway? ;)

FWIW.. Some of the native guys I occassionally hang around with thought a recent display at a museuem where folks could liquify a goldfish in a blender was pretty damn neat... And from their argument and perspective.. They're right... Only so far.. But.. They're right... ;)

One world... Many rights... And many wrongs...

Ron Shimek

The problem with the amount of waste that net-pen fish farms produces is not insignificant, nor is there any real way to utilize the stuff.

My background here is reasonable. I largely supervised the writing of the programmatic EIS for net pen fish farming for Washington in the late 1980's. As a result of that EIS, the development of net pen fish farming is very restricted in that state.

The amount of waste accumulating under and in the waters around such a facility is absolutely enormous. The sediment goes anaerobic almost immediately even in areas with significant tidal flushing. If memory serves, a net pen facility covering about 100 acres (this is a small to average size facility) produces more waste on per day basis than a city of about 20,000 people.

The sediments in areas under the pens are completely anaerobic - right up at the surface. The bottoms are typically covered in Beggiatoa (white cobweb fungus). The only animals found there are gutless bivalves that by eating on their gill surfaces. The nutrient loading can be demonstrated miles away from such facilities even in areas of signficant tidal mixing and causes alteration of the benthic communities a LONG way away from the site.

If you collect the sediment from under such a facility, it is black, oily, and laden with H2S. It is also, of course, very salty. Disturbing such sediment (as in harvesting for a secondary use) would depete the dissolved oxygen in the water column and likely cause fish kills and red tides up to several miles away.

Fun stuff, and a great place to dive....

Mike Kirda

I have been a mostly lurking member of an aquaculture ML for a number of years. The debate about salmon farming in the Pacific NW is ongoing, and at times, makes the biggest flames wars here and on Reefkeepers look like bic vs. your average forest fire.

The anti-netpen folks cite the same issues- that the nutrients go down and remain there, often forming mounds several feet higher than the surrounding seafloor. They state that they remain for years after farming has ended, and that the effects can be measured miles away. Even more disturbing to them is that the net pens are vulnerable- people have been know to cut the nets, various large predators have cut holes in them and had a great meal, etc. The farmed fish are not native to these waters and have escaped. There are reports now that the farmed fish are breeding in some rivers. There are fears that these farmed fish, once they have established a foothold, will displace the native stock of smaller Pacific salmon.

They are not so much against fish farming- they are against net pens. They would like to see land-based intensive farming of salmon instead. As far as I have read, the fish farmers do not want to go this route due to the fact that this technology is largely unproven in their eyes, as well as the fact that one has to build such a facility (read large capital outlay) and run it (i.e. pay for electricity), neither of which they currently have to do.

Who is to say who is right? It sounds so romantic- aquaculture. The reality is far less so.

Fun stuff, and a great place to dive....

Ron, only you could love diving there... LOL.

Ron Shimek

Net pens are the factory pig farms of the sea. Inland facilities MIGHT be okay, but not if done on the cheap... And EVERYTHING in that industry has been done on the cheap.

Ron, only you could love diving there... LOL.

Being sarcastic, Mike... The Pacific NW Coast of North America is the most colorful area in the world to dive (none of the pukey pastels of coral reefs) and the pens trash it for miles around. The funny thing is that I was all in favor of the pens when I started to do the EIS. At the end of the process, I was ready to go out and poison the fish and burn the pens.

Created by liquid
Last modified 2006-11-24 18:40