Farmed Fish

1
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, 2007

2
Overview

• Fish 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

3
Introduction

• Seafoods, and fish specifically, are high in
  protein, minerals and vitamins
• The fats that are present, tend to be
  polyunsaturated fatty acids
• The omega 3 fatty acids are especially important

4
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

5
Facts about fatty acids in salmon

• Most farmed salmon have slightly lower PUFAs
  than wild salmon
• However, the farmed product is still the next
  highest source of PUFAs available
• Moreover, farmers are rapidly adjusting feeds to
  increase omega 3s

6
Facts about fatty acids in other farmed fish

• Fatty acids can also be elevated in non-salmonid
  fish depending on feed ingredients
• Higher omega-3s are expensive and will likely
  require higher price
• Tilapia - Moderate in PUFAs 0.387 g/100g raw
• 0.600 g/100g cooked
• Tilapia - Moderate omega 3 FAs 0.141 g/100g raw
• 0.220 g/100g cooked
• Source USDA- ARS Lab

7
PCBs in Salmon and other fish

• One study found higher PCBs (which may be a
  carcinogen) in Scottish farmed salmon compared to
  wild fish
• Several subsequent studies found PCBs in wild
  and farmed fish, but level was dependent on PCBs
  in source water, wild prey fish or in fish feed
• Level of PCBs in all cases were minute and well
  inside safe levels and comparable to many other
  common foods

8
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 LDLs is 1 in
  2

9
PCB risk vs. cardiovascular risk

• Every technical report of PCBs in salmon has
  pointed out that heart benefits of salmon greatly
  outweigh cancer risks.
• Fish feed companies now screen feed ingredients
  for PCBs. And todays supplies of farmed fish
  are now lower in PCBs 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 PCBs in
  salmon

10
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 FDA
• http//www.cfsan.fda.gov/frf/sea-mehg.html

11
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

12
The actual EPA Advisory Brochure
Examples Shark (wild) 0.99 ppm Tilapia
(farmed) N.D. to 0.01 ppm
13
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)

14
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.

15
New Cage Designs
16
Cages for warm water marine fishes
17
Environmental concerns with conventional shrimp
culture

• Loss of mangroves and other coastal vegetation.

18
Integrated shrimp farming
19
Shrimp and Seaweeds

• Gracilaria and shrimp production in Hawaii

20
Shrimp and halophytes
21
Bivalve rearing environmentally benign
22
Concerns with eating bivalves

• Bioaccumulate toxins from algae bloomsNeurotoxic
  Shellfish PoisoningDiuretic Shellfish
  PoisoningVibrio cholera
• Do not eat wild bivalves in months without rs
• Farm raised bivalves are monitored and much safer

23
Aquaculture and fish farming

• Aquaculture is making huge advances in production
• Dozens of species of plants and animals are grown
  profitably
• Aquaculture products continue to provide more
  seafood
• Almost all aquaculture is more sustainable than
  commercial fishing

24
Aquaculture and commercial fishing

• 2005 UN-FAO reported 50 of all fish consumed
  globally were farmed
• Most species are newly domesticated
• No by-catch or ship pollution
• Much safer for workers, fishing is USs most
  dangerous occupation
• Fishing is last major hunting and gathering
  lifestyle

25
Improved processing of farmed products
26
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

27
Future of farmed seafoods

• Commercial fisheries will phase out in favor of
  sport fishing
• Farmed 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