Aquaculture: Cage Culture


Uploaded by PurdueUniversity on 24.03.2011

Transcript:
[ Background music ]
>> Narrator: Agriculture has been at the heart
of Indiana's economy for centuries.
Farmers have taken full advantage of the state's rich,
fertile soil -- from harvesting crops to raising livestock.
But now there's a new type
of farming that's gaining popularity in Indiana,
and instead of using land, it utilizes water.
[ Music ]
>> Narrator: Aquaculture -- or fish farming --
is the practice of raising and harvesting fish --
or other aquatic life -- in a controlled environment.
There are four culture systems in which you can raise fish:
Ponds, raceways, recycling systems and cages.
This video focuses on the cage cultural system [background
talking] and the necessary steps you need to take,
in order to start and maintain a successful
aquaculture operation.
[ No audio ]
[ Background music ]
>> Narrator: Before investing any capital
into a new business venture, it's always best
to examine the economics of the industry.
Doing thorough market research and developing a marketing
and business plan will help put you on a path to profitability.
You need to identify the type of markets that are available
to you, who the major players are
and the strength of the competition.
There are several factors that determine
which market will be best for your product:
From the size of your operation...
to the method of distribution -- live, frozen or processed --
to the transportation of the fish.
The markets are scalable, from home consumption
to retail sales to wholesale.
For smaller cage operations, selling direct
to the consumer will usually be the most profitable.
>> I worked at a power plant,
and I just started telling people I have fresh fish.
And word-of-mouth, I can sell everything I process every year.
>> Narrator: Farmers' markets are a great place
to sell local fresh fish to the community.
Another potential market is in selling directly
to local restaurants, grocery stores and caterers.
Live fish retailers, such as Asian grocery stores,
is another market that has a steady demand for live fish.
In order to be successful with this market, it's necessary
that you cultivate good relationships
with the various retailers and area restaurant owners.
Depending on the size of your cage operation,
selling to wholesalers
and processing plants is a possibility.
While the profit will be less than selling directly
to the consumer, the time and effort required
in selling the fish is much lower.
Although the initial capital investment is fairly low,
compared to other agribusinesses, you still need
to educate yourself on the potential markets,
if you want to have a financially-successful cage
culture operation.
Indiana Marketmaker is a comprehensive, online resource
that provides a link between producers
of agricultural products and consumers.
Talking to a practicing aquaculture farmer
in your area would be a worthwhile
educational experience.
The Purdue Aquaculture Economics
and Resources website is also a valuable resource
that you should take full advantage of.
[ No audio ]
>> Narrator: After determining
that aquaculture farming is something that you want
to pursue, the first step is to locate a body of water
that will best suit your needs.
[Background music] Make certain that your site will be able
to support the ecological and biological demands
that a cage operation places on it.
Ponds, lakes and quarries are all potential sites
for cage farming.
There are several important criteria to consider,
when selecting a site.
The size of the body of water: The surface should be
at least one half acre, but preferably an acre or larger.
The water depth should be at least 6 feet.
Adequate depth is crucial to maintain water circulation,
so oxygen can enter the densely-populated cages
and waste can be removed.
Water quality plays a significant role
in choosing the site.
You need to determine the watershed of the area.
A body of water located near land heavily populated
with livestock or crops could be problematic,
because of the possibility of animal waste
and fertilizers draining into it.
Trees surrounding the site could also be an issue,
because you need good wind exposure
to maximize the availability
of dissolved oxygen reaching the fish.
In order for fish to survive and thrive in a caged environment,
sufficient dissolved oxygen levels need to be maintained.
Therefore, selecting a site that has access
to electricity will allow you to use aeration equipment
that will sustain levels on a consistent basis.
The site you select must be accessible 365 days of the year.
Make sure the roads can be accessed in any type of weather
for feeding, observation, maintenance
and harvest of fish and cages.
Access to cages can be either by boat or pier.
This should be planned in advance, both for financial
and management considerations.
Whether the site you select is a pond on your own property,
or a lake you rent from a landowner,
you want to protect your investment by securing your site
from poachers [chain sound].
[ No audio ]
[ Background music ]
>> Narrator: You've researched the markets
and found a suitable body of water
to start your cage operation.
The next step is to decide what species of fish to raise.
This can seem like a daunting task, considering the number
of species to choose from.
But two things should guide you in your selection: Marketability
of your product and the type of aquaculture operation.
In the cage culture environment,
certain species do much better than others.
In Indiana, tilapia is a popular fish for cage farming,
because of its large size, rapid growth and hardiness.
>> You going to start raising fish in cages,
I really recommend using tilapia first.
You know, tilapia are so easy and they grow so quick.
>> Narrator: Other species that do well
in cages are hybrid striped bass, rainbow trout and catfish.
Also, large-mouth bass has shown promise in the cage environment.
You need to factor the length and time of the year
for the growing season of each species, because they vary.
For instance, tilapia
and rainbow trout each have a six-month growing season,
until they're ready for the market,
while the large-mouth bass
and hybrid striped bass take 18 months to raise.
Since tilapia is a tropical fish, it doesn't do well
in the cold, so they need
to be harvested before the water temperature drops below
60 degrees.
Obviously, they won't survive an Indiana winter.
Conversely, rainbow trout are cold-water fish
and cannot handle temperatures above 65 degrees,
and so will not grow through an Indiana summer.
Each species of fish is going to have their own set of guidelines
for growing and harvesting.
For additional guidance, you can go
to the website Indianafishfarming.com and/or
contact Purdue Extension.
[ No audio ]
[ Background music ]
>> Narrator: Once you've settled on a specie or species,
you need to select the fish hatchery
to purchase the fingerlings
that you will use to stock your cages.
A hatchery is a facility where fish eggs are hatched
in a controlled environment.
The small fish hatched
from those eggs are referred to as fingerlings.
Just like determining which species is right
for your operation, you need to do research on the hatcheries
and find one that has a reputation of dependability,
quality, fair prices and delivery rates.
Depending on the species,
the price per fingerling ranges approximately
from 25 cents to a dollar 50 cents.
The price per fingerling will decrease as the volume
of purchase increases.
For a list of commercial suppliers,
go to the Indiana Department of Natural Resources website.
When selecting fingerlings, you want to make sure
that they are all of similar size,
because you want uniform growth in the individual cages.
In order to determine size and quality, graders are used
to separate the fingerlings into common sizes.
You want to avoid runts and select fingerlings
that are as large as possible.
And be sure that cannibalistic species, like bass,
have been feed trained.
[ No audio ]
>> Narrator: One of the main factors
that will determine the number
of fingerlings purchased will be the cage size.
You want five to seven fingerlings per cage cubic foot.
[Background music] For example, if your cage is 4 feet wide,
4 feet in length, and has a depth of 4,
you have 64 cubic feet of space in your cage.
And therefore, you can stock your cage
with 320 to 448 fingerlings.
For a beginning fish farmer, it is recommended that you start
at the lower end of the stocking density range.
Cages come in all sizes, depending on the size
of the fish, but the minimum depth
of all cages should be 4 feet.
Despite the variety of cage shapes, the material used
in the construction is fairly consistent.
You can purchase cages through a supplier, fellow fish farmer
or build them yourself.
They're inexpensive to build -- $150 to $500 per cage --
and some of the material can be found
at your local hardware store, like PVC type for the frame
and a flotation device to keep the cage buoyant.
The plastic mesh -- or PVC-coated wire mesh --
to go around the frame will have to be purchased
from a specialty supplier.
Check the Web for online cage-building directions,
or contact Purdue Extension.
The mesh size you use for the cage will be determined
by the fingerling size and specie.
The size of the mesh should be no smaller than one half inch,
to maintain maximum water circulation through the cage.
To get the exact mesh size suited for a particular specie
of fish, you'll need to contact a supplier.
A cage lid is important, because it prevents the fish
from escaping and keeps predators out.
Another significant component to the cage is the feed ring.
A feed ring keeps floating feed inside the cage
and can be attached to the cage or suspended from the lid.
The placement of the cages in the water is another factor
to take into careful consideration.
If you have a multiple-cage operation, be sure there is
at least 10 feet in between each cage,
to ensure adequate water circulation.
The water depth should be at least 6 feet, with a minimum
of 2 feet of water beneath the cage,
to ensure that waste is kept away from the fish.
You also want to make sure that your cages are away
from frequent disturbances, like other animals or people.
You don't want swimming or fishing near your cages.
And finally, the cages must be easily accessible
in all weather conditions, either by pier or by boat.
[ No audio ]
>> Narrator: Water quality management is critical
to a successful aquaculture operation.
[Background water sounds,
talking]
In the densely-populated cage cultural environment,
supplying enough dissolved oxygen
to the fish [background music] can be difficult,
if a farmer relied solely on nature.
Some of the natural factors
that affect dissolved oxygen levels are water temperature,
wind, the salinity of the water and plant photosynthesis.
There is a mechanical process --
that allows you to manipulate [background sounds
and music] the dissolved oxygen concentration levels --
called aeration.
Similar to pumps used in aquariums, an aerator pumps air
through the cages, oxidizing the water in the process.
While the aeration will increase the startup costs of production,
it is well worth the investment, to reduce risk.
In cage operations, low dissolved oxygen levels in ponds
and lakes is the number one cause of most fish kills
or groat and disease outbreak.
>> Any -- you do need to aerate.
You know, a lot of people don't think that you need aeration
if you got bigger bodies of water,
but you need water moving through your cages.
And sometimes, on hot summer days, you know,
you don't get a lot of wind to get movement, so --
I really think persons need aerators, especially if you're
in the cage culture business.
>> Narrator: The dissolved oxygen level of the water needs
to be carefully monitored, as does the water temperature.
Fish growth, reproduction
and sometimes survival are all tied to water temperature.
Every species of fish will have an optimal water temperature
range for growth.
Dropping below that recommended temperature range jeopardizes
the survival of the fish.
Another issue you need to be aware of is pond turnover.
This commonly occurs in the summer, when cool,
oxygen-depleted water at the bottom of the pond is forced
by severe weather conditions to the top,
replacing the warm, oxygen-rich layer.
To prevent this natural occurrence, you pump air
into the pond bottom
and proactively mix the two layers of water.
This is called de-stratification.
Water test kits are a must for any fish farmer looking
to have a successful operation.
Along with measuring dissolved oxygen levels
and water temperature, knowing the alkalinity of the water
and ammonia levels is crucial.
Each body of water is going to have its own chemical makeup.
Your job, as a fish farmer,
is to provide an optimal environment for your fish.
In order to do that, you need to ensure
and maintain the water quality.
[ No audio ]
>> Narrator: Fish are shy animals
that are easily susceptible to stress.
[Background work sounds,
music] Cage farming is inherently stressful
on the fish, because of the direct handling
and the capturing, hauling, stocking and harvesting of fish.
Overly-taxed fish will lead to poor feeding,
which leads to stunted growth.
So you must take special care and minimize stress,
whenever handling fish.
When purchasing fingerlings,
make sure your supply has been properly graded
and is disease free.
Always try to buy your fingerlings
from a reputable supplier who will guarantee his product.
Transporting fingerlings and market-ready fish should be done
in a well-oxygenated container.
Whether you're using a commercial-sized hauler
or a container that fits in the back of a pickup,
you need to make sure the water is probably aerated.
[Aerator motor sound] The water temperature
in the hauling containers should match the water temperature the
fingerlings or fish currently inhabit.
A fluctuation in water temperature can lead
to immediate death or diseased fish.
Temper the water in the container
by adding the fish's source water, either from a tank --
if it's a fingerling -- or from the pond or lake
that you're harvesting.
For instance, for every 10-degree change in Fahrenheit,
you'll need to wait approximately 20 minutes.
Adding salt to the hauling container helps reduce stress
and can reduce certain parasites that could infect the fish.
Be sure not to overfill the containers with fish,
as it will increase the stress on the fish during transport.
Also keep in mind, the longer the travel time,
the more stress the fish will experience.
Stocking and harvesting the cages is among the most
stressful situations the fish will encounter.
A well-thought-out plan on how you'll transport the fingerling
from the hauler to the cage, or move market-ready fish
from the cage to the hauler, is of utmost importance.
Minimizing the number of steps and duration
of the process will reduce handling stress.
After stocking cages with fingerlings, don't be surprised
if the feeding response is less than expected.
The fish need to recover from the haul and adjust
to the cage environment.
Be judicious with the feed for the first couple of days.
You do not want to overfeed.
[ No audio ]
[ Background work sounds, music ]
>> Narrator: Selecting the proper feed
and following proper feeding practices is crucial
for a successful cage-farming operation.
It's unlikely the fish will receive any natural food
in the caged environment, so it's the farmer's responsibility
to feed the fish on a regular basis.
There are several types of feed on the market, and the specie
of fish will determine the one you select.
Store the feed in a dry and cool place,
and always be sure the feed is fresh and not moldy.
Whichever brand of feed you purchase,
it must provide a complete diet.
The feed also must be of the floating variety.
[Background water sounds, music] Sinking feed will fall
through the cage and not be eaten,
while the floating feed will remain trapped
within the feed ring and allow the farmer to observe the fish.
Watching feeding behavior is the best indicator
of the fish's overall health.
>> You just have to keep an eye on them and see
if they're acting right and eating, you know.
Any kind of livestock, they're not eating,
there's something wrong.
>> Narrator: Feeding method will be determined by cage location.
Hand feeding is preferred, to allow for the opportunity
to observe feeding behavior.
If the cage is located near a pier, then an auto
or demand feeder can be used
to feed the fish at regular intervals.
Be sure to properly maintain the feeder
and that it's functioning correctly.
And even though the feeding process is automated,
you still want to observe feeding behavior daily.
The fish should be fed daily, at least six days a week.
Feeding behavior will be more aggressive
when water temperature is at optimal level
and oxygen levels are high.
Between mid-morning and late afternoon is usually the best
time to feed.
Newly-stocked fish will sometimes take a little longer
to feed, as they adjust to the new environment.
Research feeding habits on the specie you're growing,
and get a better understanding of what to expect.
Feeding the correct amount to the fish is vital
to fish health -- and your bottom line.
Forty to 50% of your production cost is feed.
Over-feeding the fish will not only deteriorate water quality
and lead to stress and possibly diseased fish,
but it will also increase the amount of feed
that you'll need to purchase.
[Background music] Under-feeding will result in poor growth
and a disappointing harvest.
You'll want to feed the fish until they're satiated.
Feed them all they want to eat within a 10-
to 30-minute time span.
For a new fish farmer with little experience,
the best method to determine proper feed amounts is
by calculating weekly weights of the fish
and adjusting feed amounts accordingly.
By dividing the total weight by the number of fingerlings
at stocking, you can determine individual weight.
By checking with the table that pertains to your specie,
you can figure the proper feed amount for an individual fish.
From there, you multiply the amount of total fish weight
to obtain the feed quantity estimate.
Every week you pull a sample from the cage.
Weigh them.
Divide to find the individual weight.
Check the table, and multiply
for proper feed amount for the entire cage.
Always keep accurate records of the amount of feed that you use.
Proper feed amounts play a vital role in the health of your fish,
as does constant observation of the feeding response.
Observation is crucial in anticipating
and avoiding problems.
A change of behavior during feeding is an indicator
that you may have a health issue that needs immediate attention.
[ No audio ]
[ Background water, work sounds ]
>> Narrator: Vigilant observation
and proper handling techniques
to reduce stress are important things a farmer can do
to keep the risk of disease at a minimum.
There are other practices you'll need to perform
to maintain the health of fish.
[Background music] Keeping the cages clean
of bio-fouling organisms is important to fish wellness.
Bio-fouling is the growth of algae and/or bryozoans
on the sides and bottom of the cages.
It's a common problem that can restrict water flow in the cages
and reduce dissolved oxygen levels.
You'll need to periodically check the cages,
and if detected, remove the bio-fouling
with a stiff brush or broom.
Do not lift the cage out of the water.
And to avoid causing any stress to the fish,
remove the bio-fouling using slow movements.
Not only do you want to keep the cages free
from harmful bacteria, but you want
to make sure you keep the equipment clean as well.
After using a dip net in an individual cage,
you'll want to wash and disinfect it properly,
before you use it again.
Despite all best efforts,
at some point you will encounter diseased fish.
Poor or irregular feeding habits will be the first clue.
The outward manifestation
of disease include skin discoloration, open wounds
or lesions, fin erosions, spots and general erratic behavior.
Fish will begin to die off, and you'll need to act quickly
and get a diagnosis from an accredited diagnostic lab.
A fish specimen and water sample will need to be sent to a lab.
State conservation fisheries, extension aquaculture programs
and possibly local universities can provide this service.
In Indiana, Purdue University's Animal Disease Diagnostic Lab is
the place to send your specimens.
Once the diagnosis has been made,
the lab will recommend the best course of treatment.
This may require a consultation with a veterinarian.
You may have to switch your feed supply from normal
to a medicated feed, to combat an infection.
Chemically treating the entire pond --
or in and around the cage area -- is another option.
During any treatment, always be sure
to monitor dissolved oxygen levels and supplement
with aeration, when needed.
[ No audio ]
[ Background music ]
>> Narrator: You've made it through the growing season,
and now your fish have reached minimum market size.
It's important to note that the value
of the fish per pound does not increase once minimum market
size has been reached.
[Background work sounds] It also works in your favor
to harvest the fish as soon as they reach market size,
to avoid needless risk.
Every specie's growing season will differ in length,
and other factors affect it as well, such as weather,
size and density of fingerling stock, and time of year.
You should stop feeding the fish two days before harvesting
in warm weather, and up to a week in cooler weather.
You do this so food can move
through the fish's digestive system before hauling
and processing.
Excessive waste in the hauling tank can lead
to disease and possibly death.
Depending on your setup, the process may vary.
But it's important to be as efficient as possible
in transporting the fish from the cages to the hauler.
Keeping stress to a minimum is key to maintain fish health.
You'll need to fill your hauler with water from the pond.
Add salt to the tanks, and turn on the aeration.
Now that the hauler is ready,
bring the cage to shallower water.
This crowds the fish into a restricted area
and allows for easier access.
Scoop the fish with a clean dip net into a bucket,
and transport the fish to the hauler.
Repeat the process, filling each tank
with an equal number of fish.
[Engine sound] Now the fish are ready to take to the market
or processing facility.
[Background music] Cage culture is a popular form of aquaculture
that has many advantages that include resource flexibility,
low cost and simplified harvesting.
However, it is not without its risks.
>> The cages are an easy way to start, but still, it's farming.
There's a lot of things that can happen.
>> Narrator: Educating yourself to the proper practices is vital
to a successful operation.
While this video provided a comprehensive introduction
into cage culture, it's recommended
that you continue your education by seeking
out existing literature and advice from Purdue Extension.
[ Music ]