Using animal wastes in fish ponds

HOW ANIMAL WASTES WORK IN A POIND

How animal wastes work in a poind

· Direct feeding value of pure wastes is known to be poor.
· Wastes act by:

- stimulating phytoplankton production; and,
- acting as substrate for bacterial production (detritus).

These two processes are strongly interlinked, since phytoplanktons are a major source of detritus for bacterial production. Also, phytoplanktons, through photosynthesis, are the chief producers of dissolved oxygen in the pond used by all organisms including fish.

CHECKLIST FACTORS TO CONSIDER BEFORE USING ANIMAL WASTES

· Are wastes available already on-farm? If so, are the wastes already used? Should they be divided for use in fish culture?

Livestock wastes are often important as crop fertilizers and fuel. Consider the opportunity costs.

· Is it worth raising livestock, especially to generate wastes for aquaculture?

Consider:

· costs/difficulties of doing so (e.g., feed availability and cost; marketing difficulties; technical abilities and interest of farmers)

· inorganics are now much cheaper to use than livestock manure in many places.

MANAGEMENT FACTORS TO CONSIDER

1. Are all wastes to be used in fish culture?

It some wastes are to be used elsewhere, the wastes should be collectible prior to entering the pond (e.g., use a sump). Also, wastes should be available in larger quantities at certain periods when their use should be reduced for fish culture (e.g., during cool season).

LAYOUT/DESIGN OPTIONS

On the Pond Dike

Pens should be close to the pond to reduce labor cost of loading waste.

Over the Pond

Over the pond is usually cooler, more humid.

In the layout/design aspect, consider:

· size and number of livestock space availability/land cost; and,
· relative cost of materials.

2. Can all the wastes be collected?

Feedlot livestock are kept confined at all times so all the wastes can be collected and used.

Small-scale farmers often allow livestock to graze or scavenge during daylight hours and only confined at night. This reduces feed costs considerably, often allowing only on-farm or low-cost supplementary feeds to be given. But collectible wastes will be less.

3. Livestock may be penned at the farmer's house for security or traditional reasons; this may limit potential advantages of integration.

4. Ponds may be multifunctional:

Large animals are usually denied access to the pond because entry to and wallowing in can destroy the dikes and cause turbidity which reduces natural food production.

Maybe design the pond to allow limited access.

Fence around pond keeps Buffalo out.

Fence across pond lets Buffalo in water.

Livestock wastes vary in terms of both quantity and quality which are affected by the following factors:

· Food quality of livestock
· Species and size
· Stage in life cycle (breeder, grower, etc.)
· Solids alone or mixed with urine
· Amount of waste feed
· Contamination with bedding materials, rainwater, soil, etc.
· Method and period of storage

We are monograstrics. We are fed a high quality diet and my waste is high in nutrients.

Monograstrics

I am a ruminant. I am given a diet low in nutrients and my waste is low in nutrients. But I am cheap to feed.

MISCELLANEOUS FACTS

· Young livestock tend to feed on diets higher in protein so their wastes has more nitrogen and is better as a pond input.

· Ruminant feces contain high levels of carbon relative to nitrogen and discolor the water. Generally used alone, they give low-fish yields. Consider use of urine as it contains a better balance of nutrients.

· Laying hens are fed different diets than broiler chickens and their waste is particularly high in phosphorus

TIPS FOR PROPER WASTE APPLICATION

· First application can be done about 1-2 weeks before fish stocking to produce natural food FOR immediate fish consumption.

· Apply or load manure after sunrise (about mid-morning).

· Maintain a regular schedule or routine of application.

· Make sure that fresh water is available for flushing in case of DO depletion.

· During pond preparation, scrape off 1-2 inches of the pond bottom soil. This can SEVE as an excellent fertilizer for vegetables.

WATER QUALITY MANAGEMENT

Too much manure when loaded in fish ponds can cause dissolved oxygen (DO) depletion resulting to fish moralities. When manure loading is excessively high, too much decomposition occurs; thus, the biological oxygen demand (BOD) is high, using up the available DO.

Causes of and possible remedies for different water quality problems.

DISSOLVED OXYGEN INTO THE WATER		DISSOLVED OXYGEN USED UP IN WATER		OBSERVATIONS	CAUSES	POSSIBLE REMEDIES
Phytoplankton	Other	Phytoplankton	Other
0000 0000 0000	+ 0000 >	0000	+ 0000	green water; little surface scum; active fish behavior.	no problem.
0000 0000	+ 0000 <	0000 0	+ 0000 000	cloudy water; fish appear hungry	stocking density of fish to high	harvest some fish; add more fertilizer
0000 0000 00	+ 0 >	0000 0000	+ 0000	deep ponds; high dikes surrounded by trees	no wind-caused turbulence poor water circulation	agitation during critical periods remove wind breakers; keep water level high
0000 0000 0000 000	+ 0000	0000 0000 0000 0000 00	+0000	very green; surface scum gas bubbles	overabundance of stocking density	agitate during critical periods; add quik limite to precipitate scum; add fertilizer to stimulate growth of new plankton but afterwards ,reduce overall nutrients inputs; maintain fish at higher stocking density and/or release plankton eating fish
0000 000	+ 00	0000 0000 0	+ 0000	cloudy, still weather.	low light intensity; no natural agitation of water surface	agitation add fresh water;harvest some of the fish
0000 00	+ 0000 <	0000 0000 0	+ 0000	brown, discolored water; gas bubbles; pungent odor	overuse of poor quality manure.	use less manure and more inorganic

1 Phytoplanktons (produce dissolved oxygen during daytime but consume it at night.
2 Another source of dissolved oxygen in a static water is diffusion of atmospheric oxygen.

INDICATORS OF LOW DO

1. When plenty of fish are on the water surface gasping for air.

ater surface gasping for air

2. When air or gas bubles are observed in the water.

Gas bubles are observed in the water

3. The pond water is brownish or grayish.
4. The pond water swells pungent.

WHAT TO DO WHEN DO IS LOW

1. Stop manure bading.

2. Add fresh water into the pond. While doing so, drain water off the pond bottom.

3. Stir the pond water by striking the water surface with tree branches or other appropriate materials; row repeatedly across the pond.

4. Make provisions for flow-through system (if water is readily available).

5. Use mechanical aerators (l available).

WAYS TO MEASURE WATER TRANSPARENCY (OR TURBIDITY)

Use of a Secchie disc:

The disc is lowered into the water from a calibrated rope. If it disappears within a depth < 30 cm, the water is turbid.

Using one's hand:

With the hand strecthed forward, cup the palm and bend K towards you. in this position, slowly dip the hand into the water until the palm becomes invisible Transparency is expressed, the distance siltfrom the wrist to the end of the water mark on the arm.

if the water is turbid because of suspended sedimentary particles, spread over the pond surface chopped rice straw or hay, allowing them to settle at the pond bottom together with the silt practices.

CAUTION: Too much decomposing hay can also deplete dissolved oxygen.

pH or hydrogen ion concentration determines whether the water is acidic or alkaline. Highly acidic water (4 or balow) can result to fish kills.

METHODS TO MEASURE pH

Use of equipament as: litmus paper; pH meter; Hack kit

Practical method:

Testing the water: if water tastes sour, K is acidic. Knowing the water source: acidic water comes from swamps, bogs or water from stagnant areas.

WHAT TO DO

· Stop manure loading.
· Apply lime.

Hydrogen sulfide is a poisonous gas emitted from the pond bottom as a result of decaying and decomposing organic matter:

WAYS OF KNOWING THE PRESENCE OF HYDROGEN SULFIDE

· Emission of unpleasant odor resembling that of a rotten hard-boiled egg.
· Presence of dead fish like gobies

WHAT TO DO

Drain pond and dry pond bottom for 1 -2 weeks.

· Agitate the pond water.
· Add fresh water.
· Regulate or stop manure loading.

FISH HARVESTING METHODS TO REMOVE OFF FLAVOR

Off-flavor or muddy taste of fish harvested in manure-loaded ponds can be a serious problem if fish farmers do not follow the proper harvesting procedures. People will not buy nor eat the fish with off-flavor or muddy taste.

Fish harvesting

SUGGESTED PROCEDURES

1. Stop manure loading or delivery to the fish pond at least two days before harvesting.

2. Partialiy drain the Pond leaving about 40-50 cm water depth.

3. Harvest fish by seining before draining the pond totally. This will minimize fish mortality and the murky odor of fish associated with muddied water.

4. Transfer fish to a net enclosure installed In a pond with clean water or in holding tanks with running water and hold the fish for at least 4-6 hour..

5. Sell fish live or fresh.

Fish harvesting fish harvesting A

Fish harvesting fish harvesting B

Prepared by: RUBEN SEVILLEJA,JOSETORRES,JOHN SOLLOWS &DAVID LITTLE

FARMER-PROVENINTEGRATED AGRICULTURE-AQUACULTURE:
A TECHNOLOGY INFORMATION KIT(II RR -ICLARM)