Title: Fish Farming: Intro to Aquaculture
1Fish FarmingIntro to Aquaculture
2History
- Fish are a vital component of the human diet -
nearly half the worlds population gets the
majority of its protein from seafood - As population increases, so does demand for
seafood - But Many species - perhaps 70 or more - have
been fished to their sustainable limits or
beyond. - Fish stocks are declining
3Why are our fish stocks declining?
- Overfishing
- Bigger fishing vessels
- Better technology to find fish
- Better nets
- Higher demand
- Lag time in population drop
FAO State of World Fisheries and Aquaculture
(SOFIA) 2006 http//www.fao.org/DOCREP/007/y5600
e/y5600e00.htm
4Question
5The answer Aquaculture?
- Proponents of fish farming say that the industry
not only supplies an important food resource, it
also benefits wild stocks by reducing fishing
pressures. - However, Many fishermen and environmentalists
disagree - claim that aquaculture can degrade the habitat,
health, and genetic vigor of wild species
6Salmon Debate
- Survival rate from egg to adult of 1-2
- Declining wild populations due to overfishing and
habitat degradation - Live and dead fish important part of stream and
ocean food chains - Seabirds and marine mammals caught and killed
during fishing activities - No dyes, no antibitoics, healthier
- Survival rate from egg to adult of 80-90
- Concentrated waste cause algal blooms and low
oxygen dead zones - Higher levels of pollutants in tissues
- Less expensive and more widely available to
consumers - Color from dyes, feed antibiotics, fewer
essential fatty acids and oils
7Types of Aquaculture
8Open net pens or cages
- Anchored in offshore coastal areas
- Salmon, tuna
- Pros
- Cheap
- no by-catch
- does not deplete wild stocks
- Cons
- Waste passes to environment
- Escapees
- Disease parasites
http//www.ambhanoi.um.dk/NR/rdonlyres/92ADABED-4F
6A-4F6A-A04D-2A83242C1687/0/aquaculture3.jpg
9Ponds
- Manmade ponds, recirculating seawater
- Shrimp, catfish, tilapia
- Pros
- Cheap
- no by-catch
- does not deplete wild stocks
- Provides jobs
- Cons
- Location of ponds can destroy important habitat
(mangroves) - Untreated water contaminates local environment
- But, it CAN be treated
http//www.biology.duke.edu/bio217/2005/ncm3/pond_
liner.gif
10Raceways
- Divert water from a waterway
- Must be treated before being released back to
waterway - Rainbow trout
- Pros
- no by-catch
- does not deplete wild stocks
- Provides jobs
- Cons
- Can be costly to build
- Untreated water
- Escapees (invasive species)
http//www.lib.noaa.gov/korea/korean_aquaculture/r
aceway.files/baqbk001.jpeg
11Recirculating Systems
- Enclosed tanks
- Water is cleaned reused
- Striped bass, salmon, sturgeon
- Environmentally sound
- Pros
- Can help rebuild wild populations
- Provides jobs
- Conserves wild stocks
- Cons
- Requires a lot of energy and thus
http//www.ag.auburn.edu/fish/image_gallery/data/m
edia/77/Recirc_Kent_Seatech_jpg.jpg
12Shellfish Culture
- Ropes, plastic trays, mesh bags
- Shellfish require only clean water to survive
- Pros
- Easy to do
- Can clean up nutrient rich water
- Protects wild populations
- Problems
- Waste accumulation
- disease
http//www.whoi.edu/cms/images/oceanus/2005/6/v43n
1-kitepowell3en_10837.jpg
13Why should we bother?
- Food
- Long term economics
- Overfishing correlates with
- Low biodiversity in the environment
- Harmful algal blooms
- Beach closures
Darker color more protein obtained from seafood
14Why should we bother?
- While some recover after collapse, many do not
(or at least, have not) - Cod
- Atlantic Bluefin tuna
- Pacific Northwest Salmon
- There used to be wars over Atlantic cod, now they
are almost gone.
http//www.codgen.olsvik.info/cDNA20libraries.htm
l
15Seafood Choices
16The Promise and Perils of Fish Farming
- http//www.edf.org/page.cfm?tagID16150
17Issue Imported Fish
- The seafood Americans eat largely comes from
abroad - Problem many nations that supply us with farmed
fish do not adequately regulate these operations - Solution policymakers and fish farmers worldwide
need to implement strong standards for
aquaculture operations
18Issue Economic and ecological damage
- Some fish farming does economic and ecological
damage in the long run - example, in Thailand, Ecuador and many other
tropical nations, coastal forests of mangroves
were cut down in the past and replaced with
shrimp farms. Water degrades and farm closes no
farm OR mangrove - Problem unregulated aquaculture can destroy
ecological and human communities - Solution responsible aquaculture
19Issue Water Pollution
- Problem Some production systems allow uneaten
food, fish waste and drugs and chemicals to pass
into surrounding waters, where they can harm
ecosystems and impair water quality - Solution
- Use closed recirculating systems
- Grow more than one species (mussels raised on
ropes suspended in the ocean can help cleanse
waters polluted by salmon raised in net pens. - Minimize use of antibiotics and anti-parasite
drugs
20Issue Depleting wild fish stocks
- Problem Deplete food resources for wild cousins
of farmed fish - Farming predatory fish like salmon can use huge
amounts of small, oily wild fish like anchovies,
menhaden, mackerel and herring, leaving no food
for wild fish - 1/3 of the current annual catch has been used
for animal feed - Solution
- Farm vegetarian or semi-vegetarian fish such as
tilapia and catfish or filter-feeders like
mussels or clams - Feed predatory fish a semi-vegetarian diet
supplemented with fish byproducts
21Issue Invasive Species
- Problem Escaped farmed fish can pose serious
threats to wild fish populations by competing
with them for food and habitat and transmitting
disease and parasites - Solution
- Farm species native to the region to reduce the
potential harm from introducing a new fish
species. - Use closed systems like tanks, rather than
"leaky" net pens or cages, to prevent escapes. - Mark fish and require public reporting of
escapes, to identify culpable suppliers.
22Issue Endangering Sea Animals
- Problem To keep them from feeding on captive
fish, wildlife such as seals, sea lions and birds
are often harassed with firecrackers or loud
underwater speakers that can cause
disorientation, pain or hearing loss. - Solution
- Site farms far from places where marine mammals
live or hunt, or birds congregate. - Use tight nets to prevent access by predators to
ponds, tanks, and net cages.