LITERATURE be venomous (Dorooshi, 2012). They are different from





2.1 Catfish

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The catfish can be located around the globe.
They are mostly bottom feeders which can be search in freshwater region. Meanwhile,
they also have characteristics such as flat broad heads and obtain filament
which are called as barbel which are elongate at the entrance of its lip (A-Z
animals, 2008).

The known order for the
catfish is called Siluriformes which ranges
of almost 3000 knowns species around the world (A-Z animals, 2008). In general,
almost all catfishes are omnivores, however others have favourite diets such as
wood eating locariids (Nelson et al.,
1999) and meanwhile there can also exists such as the parasitic catfishes that
can feed on the blood of other animals such as the fish (de Pinna, 1992; Spotte,
2002). Their barbels was used to taste the foods as it contains taste buds. In
addition, it is also used to hunt as it can help detect the scent of their prey
and food in the wild. However, there are catfish that lacks the mechanism (A-Z
animals, 2008).

The catfish are prepared to
defend themselves as some are furnished with defences’ mechanism. Their
defences can resemble as sharp balances spines. It can perpetrate serious
damage to enemies (Baron et al.,
1996). Other catfish can be venomous (Dorooshi, 2012). They are different from
most freshwater fishes as they are nocturnal creatures and usually depend highly
on senses other than their sights, such as the tactual and the chemo sensitive
barbels, or a bigger olfactory organ. Thus, these creatures are able to adapt
their lives in different habitats such as holes, aquifers, and deep river
channels. Meanwhile, they also can normally leave the river and walk on land
such as the air breathing clariid catfishes (Burgess, 1989).

The general size is around
a meter and this normally depend upon the species (A-Z animals, 2008). In any case it can go in estimation
from only a centimeter long to more than two meters in length. The biggest
species is the European wels catfish, as it can found up to 5 meters long and can
weigh around 330 kg (Treeoflife, 2003). Meanwhile, the second largest is the
Mekong catfish, which is found living in different parts of the Mekong River
that streams through Laos, Thailand, Cambodia and Vietnam. The largest Mekong
catfish ever discovered was measured almost 3 meter in length.

2.2 Japanese catfish


The characteristic of the Japanese
catfish is the normal for any Silurus
species. It has a small dorsal fin which is dark grey at its sides. Their
stomach is white colour with sporadic white dabs at each side. They also obtain
barbels as any common catfish. However, the specialty of the Japanese catfish
is having one pair of the mandibular barbell which is longer than their head
while another pair of the mandibular barbell is 1/3 to 1/5 of the total length
of their maxillary barbell (Liu, 1990). During the adolescent stage, the fish
can be around 6 to 7 cm as their standard length. Also, amid this stage, they have
one additional combine of mandibular barbell however it will deteriorates as it
enters the adulthood (Atoda, 1935).

Furthermore, Japanese
catfish can create its home in or under of stream or at lake banks, old logs, shakes
or even under rocks. While others would discover openings in banks, and some
can make the gaps themselves. The spawning season will come in the spring or
late spring from May up to June. They are able to spawn eggs around 5000 up to
10000 eggs which depends on their age and size. While for their sex, it can be
seen an apparent sex ratio of the species is extremely high toward females to
males. They are intraspecific variety in their regenerative nature, especially
during mating conduct, as it has been research inside the neighbourhood
populaces in Japan (Maehata, 2007).

In Japan, a past
investigation of the Japanese catfish in almost various lake has indicates a diverse
mating conduct. For instances, in the lake Biwa populaces it had demonstrated a
settled succession of activities, for example the pursuing, the sticking, the
enclosing with pressing by the male, and by hovering of the matched fish, and
the females are constantly enveloped by a solitary male (Maehata, 2002), while
at the Ooi lake and at the Fuefuki lake, the populations does not demonstrate
such the same behavioural sequence which was the process of enfolding a
female’s body by a male. The circling by the paired fish has also not been seen
but instead the females will usually enfolded by around two different males
(Maehata, 2007). In the spawning activities, the Japanese catfish will scatter their eggs. This was believed
to be aimed at reducing the number of juvenile mortality rate (Katano et al., 1988). The male is generally the
all-time caretaker and defender of the eggs.

As the fry will continue
to grow to adult phase, their diet will begin to increases as many type of
animals such as the crustaceans, the clams and also small fish become their
food (Katano et al., 1988). In almost
all the matured adult fish are active and feed during night time. However, this
fish also feed in condition such as dirty and lower vision waters during sunlight.
The hunting method relies upon their sense of scent and taste due to the catfish
having very poor sight (Maehata, 2007). When the larvae had aged to juvenile
and become matured, they will then began to form schools and move together. Moreover,
they do not possess any
migrating characteristic such as travelling downstream and upstream river. But will spend a lot of their lives in lakes bottom, the
reservoirs and river streams.



2.3 African catfish


The African catfish is known to be a
powerful freshwater fish. It can develop to in the range  from 1.4 up to 2m long and can also weigh in
from a minimum of 8kgs up until 59kgs (Freyhof, 2016). For its characteristic,
the body colouration can fluctuates from olive green, to darker and dark with
the flanks frequently uniform dim to olive-yellow with dim slate or greenish
darker back (FAO, 2012). In its underparts, the colours are pale olive to white
and are mottled randomly with dull tanish green, or consistently gleaming

It is heavy bone with a level
headed and obtaining premaxilla while having lower jaw pointed teeth organised
in few lines. Meanwhile, it also has four pairs of long trailing sensory organs
that is recognise as barbels around its mouth (A-Z animals, 2008). In addition,
the fish has a high number of gill rakers differing from 24 to 110. The number
will increase with the size of the fish. These fish are an insatiable beast and will likely eat everything in its
sight (Ataguba et al., 2012). Their
prey also includes several organism such as the insects, the crabs, the
plankton, the snails, small fish, small birds, and many more (Ibrahem, 2011).
It is generally an individual bottom feeder, however they are known to be to a
great degree versatile to conditions and can move in groups at the water
surface. Meanwhile, it can also shows an assortment of strongly behaviour such
as sucking the surface for earthbound creepy crawlies and  also some plant pieces  that was washed into the water by overwhelming
rains and pack-hunting of small cichlids. The growth is generally rapid, where
the fish can obtain their maximum size within a couple of years (FAO, 2008).

African catfish are generally conveyed far and wide
around the world. The species can extend from South Africa up to Middle, West
and North Africa. It is likewise had been dispersed around different continent
such as the Middle East and Eastern Europe. Furthermore, they are also
additionally similarly introduce in Jordan, Lebanon, Israel and Turkey. It has
also been brought into most of the different nations in Africa, Europe, Asia
and South America. Similarly to some other species, China also introduced it
within its rice fields and is currently holding the position of among the main
producing countries (De Silva, 2010). The pattern for African catfish culture
has been increase throughout the following years since it introduction as one
of the biggest fish species in aquaculture. Even the market for African catfish
in the sub-Saharan Africa has been increasing and evolving each year (FAO,

2.4 Aquaculture production of catfish


By and large, all of the catfishes
around the globe has affected the global economy as they have esteem and are
always gathered as human utilization, pet exchanging and recreations. The
overall catch record of the freshwater and marine catfishes in 2000 has already
surpassed 500,000 metric tons (FAO, 2000). In addition, a few catfishes such as
the Flathead catfish in North America and also the Goliath catfish in South
America are being forcefully looked for angler in the angling sport (FAO,
2000). In contrary, a numerous number of catfish has been translocated and
acquaint with the new zones which makes some of the generous monetary
misfortune and could also harm common environments and local fish abundancy (Schmitt,
2016). There is significant catfish pests in North America which is the walking
catfish, C. batrachus, in Florida, and while also the Flathead
catfish, Pylodictis olivaris, in the Atlantic slope drainages
(Fuller et al., 1999).

While in Asia and the
Pacific, the family Clariidae (Clarias
spp.) had dominated the  aquaculture
production, by being up to the 80% of the total 76,000 tons catfish  which produced in 1991 (FAO, 2000). The most
cultured species were C. batrachus, C. macro-cephalus and C. gariepinus. However, only the African
catfish was the introduced species that had an important effect on the Asian
aquaculture industry (FAO, 2010). The very first introduction was done in
Vietnam of the year 1975, where the species was then spread widely all over
Asian region. Although the Asians do not find its meat quality and its large
size preferable, due to its rapid growth and hardiness of the fish, it has made
it very interesting among the fish farming business. While for the Japanese
catfish, In general, it is rapidly gaining high popularity in aquaculture
industries mostly in Asian region. It has been used cultured in Japan by many
aqua culturist. In Vietnam, the production of Japanese catfish is very high in
middle and lower section of rivers where they are harvested throughout year.
Furthermore, the Japanese catfish is
also a known sport fish due to its aggressiveness and powerful body. Generally,
fish sport person love catfish as one of the best freshwater fishing game in
the world.

2.5 Growth performance of catfish


The development of a fish can be
characterized as an increased in magnitude, it can also be estimated by their
size and also the tissue piece. It speaks to a standout amongst the most
noteworthy parameters in aquaculture (Silva et
al., 2015). Growth is
estimated by the units of the length and the weight and is best spoken to as
the important development rate. The main relationship between the weight and
the length can provides an index of the state of well-being of a fish. The condition
factor ‘K’Fishes can display a ‘determinate’ which is a sort of development in
brief types of hotter areas and an ‘indeterminate’ sort of extensive types of
colder districts (Dutta, 1994). It could also be measured by using other
criteria such as the glycine uptake by scales, the hepatosomatic index, the
RNA:DNA ratio and also the protein retention in the tissues. The nutrition
which includes the quality and quantity of food, will play an important role in
growth regulation (Siddiqui, 2014).

A few number of
environmental factors, such as the temperature, the oxygen concentration, the salinity
and the photoperiod, can also affect the rate of growth (Tang et al., 2008). There are fish that can
exhibit a determinate type of growth in short-lived species of warmer regions
and an indeterminate type in long-lived species of colder regions (Dutta,
1994). The water temperature is a standout amongst the most critical physical
variables influencing fish development and creation. Fish are cold blooded
creatures which expect around an indistinguishable temperature from their
environment (Viadero, 2005).

The growth performance of the
African catfish can be affected by many factors such as stocking density, feed
formulation and water quality. Past studies of Micha (1976) suggest that the
growth of African catfish to decrease with increasing stocking densities.
However, (Van de Nieuwegiessen et al.,
2008) had indicated that both the high and low densities had also some detrimental
effects on fish welfare based on juvenile African catfish of 10-100g. Factors
such as feed can affects the growth of African catfish by the number of protein
level contain in the feed. High level of protein is very essential to the
growth of fish but an optimum level is known better to provide high growth
efficiency (Tunde et al., 2016).

As for Japanese catfish,
the growth of the catfish was very fast and it can grew to an average body
weight, 100g at 80 days after hatching in the natural condition (Akazaki et al., 1991). The Japanese catfish had
contain less information regarding the nutrients that can help its growth but another
past studies of Cong Liu (2012) states that the dietary protein of 43% and
dietary lipid of 7% had no significant growth effect on Japanese catfish
compared to S. meridionalis which had shown better growth performance in the same
dietary nutrient. However, the Japanese catfish optimum level of dietary protein
is 45% for the best development (Kim et
al., 2014). Sex of the Japanese catfish also influences its growth
performance as female grow much faster than male (Kim et al., 2001). This is due to reaching sexual maturity has reduce
its growth rate and reduce its feed efficiency for male.