Farmed Fish – Getting the Facts Straight

Kevin Fitzsimmons, Ph.D.Professor of Environmental Science

University of Arizona, Department of Soil, Water, and Environmental Science

Tucson, Az

Feb. 19, 2009

OverviewFish and other seafood are universally

touted as highly nutritious and a key part of healthy eating

Some seafoods have been identified as contaminated or variable in nutritional values

Farmed seafoods have been reported to be more and less healthy than wild caught

Review of the science and consideration of benefits and risks

IntroductionSeafoods, and fish specifically, are

high in protein, minerals and vitaminsThe fats that are present, tend to be

polyunsaturated fatty acidsThe omega 3 fatty acids are especially

important

Remember organic chem?

Found in many marine algae, canola, walnuts, soybean, and flaxseeds

Essential part of the nutritional requirement of almost all organisms

Important in neural and cardiovascular functions

Facts about fatty acids in salmon Most farmed salmon

have slightly lower PUFA’s than wild salmon

However, the farmed product is still the next highest source of PUFA’s available

Moreover, farmers are rapidly adjusting feeds to increase omega 3’s

Facts about fatty acids in other farmed fish

Fatty acids can also be elevated in non-salmonid fish depending on feed ingredients

Higher omega-3’s are expensive and will likely require higher price

Tilapia - Moderate in PUFA’s: 0.387 g/100g raw

0.600 g/100g cooked Tilapia - Moderate omega 3 FA’s:

0.141 g/100g raw0.220 g/100g cooked

Source – USDA- ARS Lab

PCB’s in Salmon and other fish One study found higher PCB’s (which may

be a carcinogen) in Scottish farmed salmon compared to wild fish

Several subsequent studies found PCB’s in wild and farmed fish, but level was dependent on PCB’s in source water, wild prey fish or in fish feed

Level of PCB’s in all cases were minute and well inside “safe” levels and comparable to many other common foods

PCB risk vs. cardiovascular risk Risk and Benefits Levels in salmon vary from 0 to 30 ppb FDA level of concern is 2000 ppb (2ppm) EPA suggests that fish with 24 ppb or

greater should not be consumed more than once per month

Above 24 ppb increased potential for cancer may be 1 in 100,000

Comparison: Increased potential for cardio-vascular problems with high LDL’s is 1 in 2

PCB risk vs. cardiovascular risk Every technical report of PCB’s in salmon

has pointed out that heart benefits of salmon greatly outweigh cancer risks.

Fish feed companies now screen feed ingredients for PCB’s. And today’s supplies of farmed fish are now lower in PCB’s than most wild fish.

In Western US, most farmed salmon comes from southern Chile, which has little industry, very clean water and undetectable levels of PCB’s in salmon

Mercury in fish Methylmercury is a by product of coal

burning. It bio-accumulates in top predator fish in

freshwater and marine systems. In freshwater – Pike, muskies are problems In marine waters – sharks, swordfish and

tilefish are of concern for pregnant and nursing women and babies

Sources: EPA and FDAhttp://www.cfsan.fda.gov/~frf/sea-mehg.html

Mercury in fish EPA frequently publishes advisories to limit

consumption of wild freshwater fish Current advisories for several lakes in

Arizona, probably due to natural background levels in lakes

EPA advises to eat up to 2 meals of low mercury fish per week.

Farmed fishes have non-detectable levels, because they are grown in clean water and do not bio-accumulate from eating wild fish

The actual EPA Advisory Brochure

Examples: Shark (wild) = 0.99 ppm Tilapia (farmed) = N.D. to 0.01 ppm

Artificial color added Salmon and trout feeds sometimes include ingredients

that impart reddish or pink color to the flesh. Astanxanthin, canthaxanthin and beta-carotene are

commonly used. These may be plant or algae extracts, or chemically

derived. May also use whole algae as ingredient (Spirulina or

Dunaliella) Yes, the same extracts and algae sold in health food

stores, (which was not included in the scare stories)

Environmental concerns - Salmon

Some cage farms have contributed to benthic pollution in the past.

This is especially bad for the fish, so farmers rapidly moved cages to locations with more current and water flow.

Most new cages are in deep water.

New Cage Designs

Cages for warm water marine fishes

Environmental concerns with conventional

shrimp culture

Loss of mangroves and other coastal vegetation.

Integrated shrimp farming

Shrimp and SeaweedsGracilaria and shrimp production

in Hawaii

Shrimp and halophytes

Bivalve rearing – environmentally benign

Concerns with eating bivalves

Bioaccumulate toxins from algae bloomsNeurotoxic Shellfish PoisoningDiuretic Shellfish PoisoningVibrio cholera

Do not eat wild bivalves in months without “r”s

Farm raised bivalves are monitored and much safer

Aquaculture and fish farmingAquaculture is making huge advances in

productionDozens of species of plants and animals are

grown profitablyAquaculture products continue to provide more

seafoodAlmost all aquaculture is more sustainable than

commercial fishing

Aquaculture and commercial fishing

2005 UN-FAO reported 50% of all fish consumed globally were farmed

Most species are newly domesticatedNo by-catch or ship pollutionMuch safer for workers, fishing is US’s most

dangerous occupationFishing is last major “hunting and gathering”

lifestyle

Improved processing of farmed products

Competition with “wild” seafood:

US fishing industry complains about farm raised imports

Current tariffs on Norwegian salmon, Chinese crayfish, Vietnamese catfish, and shrimp from Brazil, China, Vietnam, Thailand and India

Wild fish have difficulty competing on price, quality and consistency

Future of farmed seafoodsCommercial fisheries will phase out in

favor of sport fishingFarmed products will account for vast

majority of seafood.Environmental sustainability is

increasing rapidly and will be achieved well before land farming.

Price and quality will continue to improve rapidly