CAGE CULTURE IN LAGOS 

Lagos State Government under the the able leadership of His Excellency Mr. Babatunde Raji Fashola initiated the idea of economical use of open water for fisheries development in Lagos State for fish culture and improving the living standard of the rural fisherfolks in Lagos.

The EXCELLENT GOVERNOR IS SO PASSIONATE about the rural fisherfolks that he approved fund for the take off the fish cage and pen culture in Lagos State . The project pioneered the use of open water for fish culture at the inception of the project in 2007,six(6) river communities in Lagos namely -ISE , BADORE, EPE, BADAGRY, OJO - OTOAWORI,AND IJEDE IKORODU .

 PRESENTLY  CAGE CULTURE IS THE MOST ECONOMICAL WAY OF CULTURING DIVERSE SPECIES OF FISH IN ABUNDANT OPEN WATER IN LAGOS .
THANK TO BRF INITIATIVES ON AQUACULTURE.

INTRODUCTION

Lagos State is endowed with a long coastline of about 180km, a large area of inshore waters and vast and intricate systems of lakes, rivers, creeks, and Lagoons, all of which can support fish life.

The coastline i.e Semepoji in Kweme  Beach , Badagry LGA to Aboreji in Ibeju Lekki LGA , Its boundary with Ogun State.

The extent of its continental shelf into the sea is 15 Nautical miles or 30 kilometer.

Lagos state has a good network of inland waters like river oshun, sumoge, Ogun yewa ologe , aye solodo, owo and shasha  with all emptying  into the Lagos lagoon.

 WHY FISH ?

1.       Fish Provides The Body With Cheap Animal Proteins Which Are Vital For Good Health

2.       It Supplements Other Sources Of Animal  Protein That Have Been On The Decline

3.       It Is Readily Acceptable Nationally

SOURCES OF FISH PRODUCTION

CAPTURE FISHERIES – This entails fish hunting in the wild, namely .streams, reservoir, rivers , lakes ,lagoon and the sea.

CULTURE FISHERIES –This is the art of growing fish fingerlings , oysters , shrimps , periwinkles, clams  etc to

table size in enclosed  water bodies  such as pond s, lakes , reservoirs , tanks , pens , cages , and dams.

WHY FISH FARMING?

·         It is cheaper and more reliable method of producing fish

·         It utilizes vast available untapped land and water resources.

·         It converts  to useful purposes land otherwise not suitable for any other forms of agricultural practices e.g. swamps, wetlands  spent lands , burrows , excavation pits etc.

·         It reduces pressure on the fishing in the natural waters.

·         It restocks the natural water bodies with fingerlings.

·         It helps generate employment both in rural and urban areas.

·         It is convenient to practice within living environment.

·          

CAGE AND PEN FISH CULTURE SYSTEM

Cage culture involves placing a mesh or wire cage in a flowing open water system, such as a lake, stream, and reservoir or ocean while water flows freely through it.  Originally, cages were used by fishermen to hold their catch until the fish were ready to sell.  The constant water flow is critical as it renews the oxygen supply and removes waste products with little effort by the aquaculturist.   The size of mesh used for the cage is critical as it must prevent the entry of predators, while holding the valuable fish stock.

Cage culture is often advantageous because it can be practiced on a small scale is almost any body of water.   In addition, cage culture is relatively unobtrusive to the landscape and leaves opportunity for the water to be used in other ways, such as recreational fishing.  Unfortunately, the closed, confined

environment often leads to the rapid spread of disease in the caged community. 

TYPES OF CAGES

Fixed, floating, submersible and submerged

FIXED CAGE: cage is essentially a net bag supported by posts which are anchored to the bottom of a river or lake.  Although they are inexpensive, their use is limited to shallow, protected water with soft substrates.

FLOATING CAGE:

Floating cages are made from netting supported by a buoyant collar or a stable frame.  This is the most widely used method of cage aquaculture because the cages can be made any size or shape.

SUBMERSIBLE CAGE:

These cages are built with a rigid frame and because they are submersible, they can be moved up and down in the water column to take advantage of water conditions.  If the weather is rough, the cage is lowered to calmer water, but in calm condition the cage is lowered to calmer water, but in calm conditions the cage remains near the surface.

SUBMERGED CAGE:

These cages are the least common and are permanently kept under the water.  This is the system of operating fish cages on the high seas, here the practices is highly intensive with all operations mechanized .

Mariculture can be environmentally and economically sustainable means of production when properly planned and managed

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QUALITY OF FISH FOR CULTURE IN CAGES

• Tolerance to over crowding
• Fast growing
• Acceptance of supplementary feed
• Ability to make use of available natural fish food in  the water body
• High resistance to disease
• Ease of getting the juvenile stock and ease of breeding
• Good market value

CULTURABLE SPECIES IN CAGE AND SALINITY TOLERANCE LEVEL

SPECIES	CONSUMER ACCEPTANCE	LOCAL NAME	PERIOD/DURATION OF CULTURE	FEEDING HABBITS	SALINITY TOLERANCE	REMARKS
Tilapia rendalli Tilapia nilotica Tilapia galilea Tilapia zilli	average	epiya	Year round and adequate Can be grown in Epe , Badagry ,Ikorodu	Algae ,phytoplankton and supplementary feed	0 - 26ppt depending on species	Hardy and good, unpopular because of uncontrolled breeding
Chrysicthys nigrodigitatus	Very good	obokun	Year round but inadequate Cn be grown in Badagry , Epe , Baiyeku ,Badore , Ijede	Bivalves, supplementary feed G.N.C and P.K.C essential.	0 - 26	Hardy and grow well on supplementary feed and can be poly cultured with tilapia
Clarias gariepinus	Very good	Aro,abori,aso	Year round Badagry and Epe	Omnivorous , and supplementary feed very necessary	0 -25ppt	Can be stocked densely  and provided supplementary feed, and result in 4 month is tremendous if good breed stocked
Heterotis niloticus	Low	aika	Seasonal Can be grown Epe,and Badagry	phytoplankton	0 -35	Thrives in cage with high flow rate
Lates niloticus	Very good	giwaruwa	Scarce Badagry and Epe	predatory	Fresh water only
Gymnarchus niloticus	Good	osan	Not readily available	predatory	1 –above 30	Good predator
Heterobranchus bidorsalis	Good	abori	Seasonal	omnivorous	Fresh water	Respond well to supplementary feeds
Megalops atlanticus	Good	ede	Seasonal	predatory	5 -30ppt
Mugil cephalus mullet		atoko

*Source: modified after , Sivalingam,1973,Ezenwa,1975and 1979

PICTURES OF FISH CULTURE IN CAGES

  

SITE SELECTIONS

Where can fish farming in cages be practiced?

• Lakes
• Slow flowing rivers
• Drinking water reservoir
• Dams
• Irrigation canals
• Mining paddocks / pools
• Burrow pits
• Sea

FACTORS FOR SELECTING A SITE FOR THE CAGE CULTURE:

What are the factors to be considered for the selection of a site for cage culture?

1.       GOOD WATER QUALITY: fresh or brackish water must be of good quality not polluted or waste effluents discharged into the system, also not close to area with heavy dredging activities.

2.       Ph: The pH level of the selected site must be between 6.5 – 8.0 which will enable the culture of wide range of fish.

3.       DISSOLVED OXYGEN LEVEL: The level of dissolved oxygen must not be less than 5 mg/liter hence attention must be paid to the oxygen level of the particular selected site.

4.        

5.       TURBID  OR POLLUTED  WATER : Turbid  or polluted water are not ideal for cages or pen culture

6.       WATER CURRENT; Water current of 20 -50 cm per second is good for production of Tilapia in cages. Much less flow rate or current is recommended for production of clarias species in cages.

7.       Depth of the lagoon should be determined, in other to get an accurate placement for the cage; the depth choice should not be less than 10 – 15 feet. This will enable less biofouling of the cage.

8.       STOCK AVAILABILITY: Ready availability of fingerlings, juveniles and post juveniles for stocking the cages is important. The choice of fish to be stocked should be placed in consideration, because the type of aquatic environment will determine to a large extent the type of fish that can be cultured.

9.       FREEDOM FROM PREDATOR: The cages should be well secured from the wild predators prevalent in the selected site.

9.SIZE OF CAGES: This is also very important as the size of cage should be manageable   and such that ease of maneuvering during harvest and stocking is easy.

SITE QUALITY ANALYSIS:

The water quality of the proposed site should be determine by,

·         Water analysis .

·         Current rate determination.

·         Substratum soil grabs analysis.

·         Culture biology and species determination.

WATER ANALYSIS:

This is done by taking a sample of the lagoon , lake or reservoir water and conducting chemical analysis of the sample to determine parameters such as PH, D.O, salinity, and other necessary parameter.

CURRENT DETERMINATION:

The simplest way of determining the current of the water or lagoon is to establish the flow direction, after which two stations A and B is marked out 10 meters apart

Once this is done drop a paper boat at point A  and determine time it took the paper boat to get to  point B. do these several times to determine the current of the selected site , this is especially very useful when cage is going to be established on a flowing stream.

The current is then determined by dividing 10 meters by the time (seconds).

Also, more valuable is local reports of the current direction from local fisherman and prevalent wild animal species in the area.

                                  CULTURE BIOLOGY

Knowledge of the culture biology of each species is crucial in optimizing production from        cages. The species chosen is based on number of biological factors – omnivorous, hardy, fast growing, good food conversion, seed availability, and economical criteria – marketability and demand.The prevailing condition of the culture site. The environment requirement of each species like salinity, dissolved oxygen, pH will also determine the species selection for culture.

 MATERIALS , DESIGN AND CONSTRUCTION OF THE CAGE :

  

 

                                                                                     THE SINKER:

 

 BIOFOULING

BIOFOULING is a major problem of cages  in tropical waters , the net walls , floaters  can be covered by biofoulers  which serves as excellent  habitats formed by  sedimentation of silts  particles , for  smaller organisms  such as amphipods,polychoates ,isopods  etc .

Mechanical cleaning of cages should be carried out.

 

bamboo frame cage in  large earthen reservoir

Above all the vast water networks are put to productive usage as more opportunity in fisheries is unfolded

Aquaculture has demonstrated its full potential as a viable system of animal production and husbandry to increase fish production and supply and improving rural economy.

For Further Enquiries contact 

Project officer,

Marine agriculture development project,

08034545145