Review: Abdel Rahman El Gamal (Founder of the
Lotus-aquaculture culture system
has been practiced for long time in China and is being evaluated recently in
some Asian countries where lotus (Nelumbo
nucifera) is native macrophytes. Several fish
species have been used in such integrated systems including carps, tilapias and
The two culture forms are either
the co-culturing of two crops in the same field and for the same time or apply
the rotation type in which the culture of each crop is done individually in a
one after another pattern.
The evaluation of lotus-aquaculture
systems has always considered the technical as well as the economics of such
integrated systems. Even the outcomes of the two forms varied and could be
related to the culture conditions, there have been some agreements. For
example, in the co-culture form, the shading resulting from the shading of
lotus leaves which reduce the phytoplankton production and hence the dissolved
oxygen in the water. Added to that, if the dead water leaves were not removed
from the pond, they decompose and worsen the dissolved oxygen situation which
is not in favor of fish production.
Regarding the lotus, fish can feed
on aquatic grasses that may compete with lotus for living resources. Also, fish
excreta would be a good source of organic fertilizers that leads to enhanced
lotus growth. Feeding fish on harmful
pests is another benefit of such co-culture method.
On the rotation form of lotus-aquaculture, the main advantage is having
two different crops instead of one bigger crop. Also, the fish crop would
assist in releasing the trapped nutrients from the pond bottom to be usable in
the subsequent culture of lotus in an ideal recycling
Photo credit: Vaghih El Bechiry (Mauritania) Description: Vaghih El Bechiry and
Abdel Rahman El Gamal (Founder of the website)
The inserted picture
shows a group of fishermen while fishing in Gorgol River “Gorgol Noir” which is
an open fishery resource and hence there is no fishing license is required. In
order to achieve enough sustainability of fishery resource, the fishery
department determines the mesh size of the fishing seines to be not less than
40mm. There is ongoing stock enhancing program whereas fish fingerlings are
stocked in the river. In fact, the plan is to establish a fish hatchery in Lakleta
for supporting the stock enhancement program.
Photo credit: Nyro Tum (Cambodia) Description: Nyro Tum and Abdel Rahman El Gamal (Founder of the website)
The inserted picture shows a field day tailored to make
potential small-scale farmers acquainted with aquaculture. Field days are
typically conducted to train farmers who are already practicing fish farming
targeting to introduce enhanced technologies and/or addressing current
problems. Preparing such field days usually requires technical and financial information.
Photo credit: KIVA Review: Abdel Rahman El Gamal (Founder of the website)
Senegal, the mangrove roots and mud are home of several hundreds of known
species of fish, bivalves and oysters, and crustaceans, which are very
important especially for domestic consumption.
are the ones who are in charge of the collection of oyster from mangrove
forests as well as in the processing of collected oysters. Women have the experience
in identifying the sites that are still in good condition in regard to the
oyster density and those with low density or exhausted.
access the mangrove sites either on foot or in small rowing canoes. For oyster
harvesting, women use simple tools are simple including a spoon to dig up the
shells, a knife for the oysters, and baskets for the harvest. Upon harvesting,
women have the experience that the practice needs to preserve the resource
mainly through keeping the green (live) roots of the mangroves undamaged except
in certain conditions such as the wood is dead or when the roots are very dense
bearing in mind that the roots of mangrove trees where the oysters are found.
After harvesting, women
also process the harvested oyster. They usually have the experience to crave
the oysters out of their shells using a proper knife.
Video credit: Mohamed Atta (Egypt) Review: Abdel Rahman El Gamal (Founder of the video channel)
Vietnam has the lead in the production of striped catfish (Pangasius sp.)
that is exported to over 100 countries. According to FAO statistics, about 1.3
million tons of Pangasius has been produced from aquaculture in 2018.
The culture of Pangasius is mainly practiced in cages,
earthen ponds and to a lesser extent in pens.
The inserted video shows the feeding of Pangasius in a commercial fish pond where a small boat is used to spread the feed within the pond. The aggressive feeding is quite obvious as shown in the video. Typically, the stocking rate rages from 20-40 fish/m2, increasing to higher rates in intensive practices with a production of about 250-300 tons/ha/crop. On the average, Pangasius can reach 1.0 – 1.5 kg as an average size after 6 months which is an optimum size for the market.
Photo credit: Vaghih El Bechiry (Mauritania) Description: Vqghih El Bechiry and Abdel Rahman El Gamal (Founder of the website)
The fish display shown in the picture exists in
the central market located in Mokama city, South of Mauritania. The fish
displayed in the market are caught from Foum Laklet Lake about 80 km from
Mokama. Fish during transportation is usually iced. As normally the case, the
man shown in the photo is the fish seller while the buyer is the woman.
Fish displays are often dominated by tilapia,
followed by bayad (Bagrus bayad). During the rainy season, African catfish (Clarias
gariepinus) contribute to the fish trade in the market. In addition to the
mentioned species, other less important species may be displayed in the market.
As the case with traditional fish market, there
are wholesalers who deal directly with fishermen while retailers have their
displays and sell directly to fish buyers.
It may worth noting that the capture fish
production from Mauritania in 2017 amounted 794,580 tons while the per capita
consumption of fish was 8.2 kg/year in 2016 bearing in mind that most of
produced fish is exported (449, 835 tons in 2016).
Photo credit: Ariel
Montiel Benitez (Paraguay) Review:
Ariel Montiel Benitez and Abdel Rahman El Gamal (Founder of the website)
Pacu (Piaractus mesopotamicus) is
an important fish species with high commercial value in Paraguay. The
availability of sufficient number of the species fingerlings would be essential
towards the expansion of pacu aquaculture in Paraguay.
The artificial reproduction of Pacu is
essential to stimulate the spawning in captivity. This has been practiced in
Paraguay whereas Prostaglandin F (PGF) and carp
pituitary extract (CPE) have been used. The inserted picture shows a
batch of Pacu eggs produced through artificial spawning
It may worth noting that according to FAO
statistics, the production of farmed pacu increased from 308 tons in 2010 to
2432 tons in 2018.
Photo credit: John Chiseba Mwamba (Zambia) Description: Abdel Rahman El Gamal (Founder of the website)
As silt accumulates,
the overall capacity of a pond decreases. Fish ponds which were not desilted
for years, ponds had become shallow, which may aggravate weed growth.
Silt can lead to pond turbidity which interferes with
the sunlight penetration and hence limits the phytoplankton production which is
the base of the food chain and ultimately affects fish production.
In spawning ponds, silt
and mud can cover fish eggs and can also hide the fish feed –in case of sinking
feed- and make it inaccessible to pond fish.
De-silting of earthen ponds is a typical and periodic operation carried
out from time to time. In small ponds as shown in the inserted picture, the
de-silting is done manually while machinery such as dredgers, excavators, sludge pumps and agitators may
be used in larger operations and lakes.
Photo and briefing credit: John Chiseba Mwamba (Zambia) Review: Abdel Rahman El Gamal (Founder of the website)
Historic use of
The long winged reproductive termite is edible and highly sought after as a
delicacy. Moreover, wild-caught termites have been used as a bait to attract
fish and insectivorous birds. Natives of South East Africa consume queens of
termites as a delicious dish.
Nutritional merit of termites: The composite
analysis of termites showed a relatively high content of crude protein of about
43 to 45% with an adequate profile of amino acids especially in its high lysine
content which is an advantageous bearing in mind that lysine is limited in most
plant protein sources. The significant high lipid content of termites (~30%) is
also advantageous whenever in energy supply and/or in providing specific fatty
acids. The overall nutritional merit of termites supports its use in fish feed
in a partial replacement of fish meal that is usually the most expensive
component of fish feed.
Present and potential use of termites in fish feed: During swarming,
significant termite populations are wasted and could be utilized for fish feed
production especially fish were observed to consume live termites when they
fall into fish pond.
Termite is used
regularly as feed ingredient in fish farms in several Asian countries including
Cambodia, Thailand and Nepal.On experimental scale, the use of termite has been tested upon partial replacement of
fish meal in the feed of “rambur – Macrotermes subhyalinus”, “mud catfish –
Heterobranchus longifilis”, “Freshwater prawn – Macrobrachium rosenbergii), and
maybe others. The outcomes of most studies recommended replacement ratios in
the feed of tested species without affecting its productive performance. The main objectives of the mentioned studies
were to explore practical means to reduce the feed cost through a partial
replacement of fish meal with a cheaper source of protein; termites.
Photo credit: Andres Delgado (Colombia) Review: Andres Delgado and Abdel Rahman El Gamal (Founder of the website)
The inserted pictures show
the culture of red tilapia in small ponds at Ricaurte which is a town
and municipality in the Nariño Department
(Colombia). In such small ponds, extensive farming system is typically applied
as locally available feed is made of sown forages that are grown around the
pond. As shown in the picture, a mesh nets are used to protect the farmed fish
against possible predation by birds and/or mammals. In such system, an average
size of about 300 g for harvested fish has been achieved after 8 months of culture.