Sep 07 2014

Self-securing the farm requirement of tilapia fingerlings in Ghana

Credit: Patrick Appenteng (Ghana)

Aquaculture presents a promising sector in Ghana as more and more people develop interest in fish farming. However, the inadequate supply of fingerlings as the demand increases and the supply by the few hatcheries setups decrease, together with the relatively high prices of fingerlings as a result of high feed prices had left most farmers with no choice than to start their own hatcheries in subsistence manner to feed their farms.

This picture shows a brood stock unit by a farmers consisting of hapa’s in an earthen pond, supported primarily by local materials of bamboo and wooden boards.

Self securing of farm requirement of tilapia fingerlings in Ghana

 

Permanent link to this article: https://fishconsult.org/?p=11652

Sep 05 2014

Mechanical control of aquatic plants in fish ponds

Both photos show the cut-plants which resulted from mechanical devices whether mechanized cutters in Egypt or handy cutters in Mexico. Regardless the place, the same rules apply as long as the weed cutting is done in the presence of fish stocks.

The effectiveness of weed cutting is only achieved when all cut weeds are immediately and completely removed from the water; each un-removed plant fragment has the potential to form a new weed. Also, cut plants left in the water will decay and release nutrients that stimulate future weed growths. Moreover, the plant decomposing would require and use a part of the pond dissolved oxygen use oxygen and can lead to fish stress or even fish kills. This matter becomes more dangerous in warmer temperatures whereas the rate of decay is faster, the requirement of oxygen by fish is higher and the holding capacity of water to oxygen is lower.

Mechanical weed control (Egypt) weed cotter Mechnical control of aquatic plants (Mexico)

 

 

Permanent link to this article: https://fishconsult.org/?p=11649

Sep 05 2014

Lebsha fishing in Lake Burullus (Egypt) – an effective practice but unfortunately illegal

Photo credit: Magd Al-Bawaab (Egypt)

Description: Abdel Rahman El Gamal (Founder of the website)

 

In this briefing I try to describe how some fishermen are practicing this “Lebsha fishing” in Lake Burullus, Egypt and hence I am not discussing the ill-legality of the said practice.

In this method, fishermen brings in a biomass of water hyacinth –which is already there in the lake- and place it in a chosen spot which is believed a good fishing place. According to fishermen’s experience, fish will be attracted to the water hyacinth zone as they enjoy the shelter and continue to grow. Fish would enjoy a free access for a period of time as determined by the fishermen’s who confine the chosen area using nets of appropriate mesh that retains the target size of fish inside. Afterwards, the water hyacinth is moved outside the enclosed zone and fish retained inside are captured and the same process is repeated again and again.

Lebsha fishing in Burullus (02) Lebsha fishing in Burullus (01)

 

Permanent link to this article: https://fishconsult.org/?p=11642

Sep 03 2014

Night fishing on the Nam Ngum reservoir in Laos

Photo credit: MK19 – Fisheries and Aquaculture Production in Reservoirs in Lao PDR

Technical review: Abdel Rahman El Gamal (Founder of the website)

As known in fishing practices, some fish species are attracted to light during dark nights and hence that are only caught during nights. In Nam Ngum reservoir (Laos), the preparation for night fishing including light sources and fishing gears and before that the fishermen who have the experience and/or prefer night fishing.

Kerosene lamps are the common source of light. During night fishing, the lamps are hung over the water surface on floating rafts to form a big circle. The fishers row from one lamp to another, shielding each one lamp at a time to focus the light at one spot in the water, and start scooping fish concentrated in that spot using hand-lift nets (shown in the photo). Most of the night catch consists of many of clupeids and small pelagic herrings. The hand-lift net (scoop net) is a pyramid-shaped net mounted on a Y-shaped bamboo frame.

The night fishing trip is over once the day light floods. Then, fishermen take their catch back to one of the trade points. The fishing boat is often taken out by another fisherman who fishes during the day making the fishing activity in Nam Ngum reservoir a 24-hour business. While women and men are engaged in day fishing, the night fishing is normally done by men.

Laos - Hand lift scoop net

 

 

Permanent link to this article: https://fishconsult.org/?p=11635

Sep 03 2014

Lake Inle fishery and the livelihood of lake communities (Myanmar)

Credit of the photo & part of the information: Mission report on inland aquaculture and fisheries, Rap publication 2003/18

Technical review: Abdel Rahman El Gamal (Founder of the website)

The photo shows a fisherman while transporting small fishing traps to be set across Lake Inle. This freshwater lake is the second largest lake in Myanmar in Southern Shan State with an estimated surface area of about 116 km2. The lake is one of the highest lakes with at an elevation of about 900 m above sea level. The average water depth of the lake is about 2.1 m during the dry season increasing to about 3.7 m during the monsoon season.

The lake hosts a unique endemic species of fish and snails including but not limited to silver-blue scaleless Sawbwa barb, the crossbanded dwarf danio, and the Lake Inle danio. Even though most of the lake fishery is not of significant importance in regard to monetary value, its social scope to the lake communities is crucial.  The fish consumption of the lake catch corrects the amino acid profile of the rice-based diets,  provides essential minerals such as calcium and sulphurous amino acids as well as the iodine which is an essential trace mineral against “goiter” that is a common debility in the lake region.

Lake Inle fishery (Myanmar)

 

 

Permanent link to this article: https://fishconsult.org/?p=11631

Sep 01 2014

Promoting sustainable aquaculture among generations in Ghana

Credit: Patrick Appenteng (Ghana)

In Ghana, we believe that for aquaculture to stay with the people in a community, the various stakeholders and key players in the community need to be brought on board. The insert shows the opinion leader, who also doubles up as the leader of the community outreach fish farm delivering a speech to his local people in the Asuogyaman District. Looking on is the local chief and other opinion leaders in the community. The insert below, also shows school children (future leaders) present at the community gathering.

In fact, this picture was taken when a delegation from the U.S Embassy in Ghana visited the community as they had assisted them in establishing cage aquaculture.

Sustainability of aquaculture among generations in Ghana Sustainability of aquaculture among generations in Ghana (02)

 

 

Permanent link to this article: https://fishconsult.org/?p=11626

Aug 30 2014

Large-scale Chinese tilapia hatchery and the marketing of GIFT strain

Photo credit:Kevin Fitzsimmons (USA)

Review: Abdel Rahman El Gamal (Founder of the website)

The photo shows a part of a tilapia hatchery facility located in Hainan Province, China. Based on various information sources, the production capacity of the said hatchery is about 400 million of sex reversed tilapia fingerlings per year. This contribution to the Chinese market of tilapia fingerlings is significant.

According to a Public-Private Partnership, an agreement between this operation “GenoMar” and “GIFT Foundation International Inc. (GFII)” has been established. Based on this agreement, GenoMar acquired the commercial right to the marketing of the Genetically Improved Farmed Tilapia strain “GIFT”  strain under the name GenoMar Supreme Tilapia in the Philippines, Brazil and China as well as continuing the research and development that began with GFII.

China GenoMar hatchery

 

 

 

Permanent link to this article: https://fishconsult.org/?p=11621

Aug 29 2014

Culture of the red algae, Kappaphycus seaweed in Vietnam

Photo credit: Ahmad Yousef alqarain (Jordan)

Review: Abdel Rahman El Gamal (Founder of the website)

In 1993, Kappaphycus alvarezii seaweed was the first time to be cultured at experimental bases in Son Hai lagoon, Vietnam. Since then, the culture of this species steadily expanded and turned to an economic activity from 1995 onward especially in the coastal areas especially when found an income generator activity to the poor fishers in these areas bearing in mind the low initial investment for their culture along with the simple technology required. The Vietnamese farmers cultivate Kappaphycus alvarezii mainly in shrimp ponds, salt fields, and coastal tidal flats. The inserted photo shows the culture of Kappaphycus in a shrimp pond in Vietnam.

The Kappaphycus alvarezii enjoy a good market as well as multiple uses including its use as dietary elements, in cosmetics and pharmacy.  This seaweed also contributes to ecosystem balancing and environment cleaning in coastal aquaculture ponds such as shrimp ponds. Some shrimp farmers integrate seaweed culture into their farming systems to enable filtering the pond discharges and reducing the loads of some nutrients.

While some households were able to recover losses from shrimp diseases through the cultivation of this species of seaweed, the public authorities in some districts encourage the cultivation of Kappaphycus alvarezii seaweed as a means to reducing the fishing pressure in coastal areas.

Kappaphycusseaweed in shrimp ponds in Vietnam

 

 

 

 

Permanent link to this article: https://fishconsult.org/?p=11612

Aug 28 2014

Temporarily crowding of tilapia fingerlings – Video

Video credit: Fadhili Ruzika (Tanzania)

Review: Abdel Rahman El Gamal (Founder of the website and video channel)

 

This video was filmed during July 2014 in a private tilapia hatchery in Kafr El Sheikh, Egypt. The fingerlings shown in this video are for all-male Nile tilapia, Oreochromis niloticus. What could be drawn from the video is the observed healthy condition of fingerlings. Also, the size of fingerlings is relatively larger than those disseminated from the hatchery early in the growing season (e.g. May). Usually the demand on all-male tilapia is at highest during late April and the whole of May whereas this timing allows for a long growing season and heavier harvested fish assuming this is economically justified.

The temporarily holding would help in the conditioning of fingerlings for packing, shipping as well for allowing fish to empty their guts. However, excessive holding is not recommended as it turns stressing to fish due to their swimming against water current along with the energy requirement for that.

 

Temporarily crowding of tilapia fingerlings

 

 

 

 

Permanent link to this article: https://fishconsult.org/?p=11594

Aug 27 2014

Scallop spat collection

Photo credit: Wilder Rodrìguez Arteaga (Peru)

Review: Abdel Rahman El Gamal (Founder of the website)

Historically, the collection of scallop spat from the wild has been the most common practice for obtaining young scallops as required for aquaculture operations or stock enhancement programs.

No matter how much methods or collection gears vary, the idea behind the process is almost the same by letting the scallop larvae to pass through the mesh of the collector to be attached to selected substrates on which they start to grow and metamorphosis into post-larvae (spat) that are collected and transferred to scallop farming facilities for on-growing.

During the early days, the onion sacks filled with fine mesh netting were used for the collection of scallop spat; they were already available. The bags used for scallop spat collection are still called onion sacks by some people.

The enhancement in the spat collection process resulted in variety of sacs of different meshes and filling materials. In the present, the spat collection bags are made from knotted polyethylene. There are two parameters which should be considered in determining the mesh size of spat bags; the species of the scallop and so there size as well as the hydrographic conditions, particularly the degree of siltation. The mesh size varies from 0.75mm for very deep water or slow growth areas of the spat; 1.5mm for standard growth; and 3.0mm for rich oceans.

Spat bags as shown in the photo are filled with artificial substrates such as mono filamentous fibers or soft netlon; there are other filling materials that are also in use.

A 50-100 m-line system of spat collectors are set in areas known by its high scallop productivity; the collector line is anchored to the seafloor. Collections can vary from less than 100 spats to more than 500 spat per beg.

Scallop spat collection

 

 

Permanent link to this article: https://fishconsult.org/?p=11586

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