2.1 Catfish The catfish can be located around the globe.They are mostly bottom feeders which can be found in the freshwater region. Meanwhile,they also have characteristics such as flat broad heads and have filament whichare called as barbels that elongate at the opening of the mouth (A-Z animals,2008). The order for the catfishis called Siluriformes which rangesof almost 3000 knowns species around the world (A-Z animals, 2008). In general,almost all catfishes are omnivores, however others have favourite diets such aswood eating locariids (Nelson et al.,1999) and meanwhile there can also exists such parasitic catfishes that feed onthe blood of other animals such as the fish (de Pinna, 1992; Spotte, 2002).
Theirbarbels was used to taste the foods as it contains taste buds. In addition, it isalso used to hunt as it can help detect the scent of their prey and food in thewild. However, there are catfish that lacks the mechanism (A-Z animals, 2008).The catfish are prepared todefend themselves as some are furnished with defences’ mechanism.
Their defencescan resemble as sharp balances spines. It can perpetrate serious damage to enemies(Baron et al., 1996). Other catfishcan be venomous (Dorooshi, 2012). They are different from most freshwaterfishes as they are nocturnal creatures and usually depend highly on sensesother than their sights, such as the tactile and the chemo sensitive barbels,or a bigger olfactory organs. Thus, these creatures are able to adapt theirlives 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 breathingclariid catfishes (Burgess, 1989).
The general size is arounda meter and this normally somewhat less relying upon the species (A-Z animals,2008). In any case it cango 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 5meters long and can weigh around 330 kg (Treeoflife, 2003). Meanwhile, thesecond largest is the Mekong catfish, which is found living in different partsof the Mekong River that streams through Laos, Thailand, Cambodia and Vietnam.The largest Mekong catfish ever discovered was measured almost 3 meter inlength.
2.2 Japanese catfish The characteristic of the Japanesecatfish is the normal for any Silurusspecies. It has a small dorsal fin which is dark grey at its sides.
Theirstomach is white colour with sporadic white dabs at each side. They also obtainbarbels as any common catfish. However, the specialty of the Japanese catfishis having one pair of the mandibular barbell which is longer than their headwhile another pair of the mandibular barbell is 1/3 to 1/5 of the total lengthof their maxillary barbell (Liu, 1990). During the adolescent stage, this fishis around 6-7 cm as their standard length. Also, amid this stage, they have oneadditional combine of mandibular barbell however it will deteriorates as itenters the adulthood (Atoda, 1935). The Japanese catfish cancreate its home in or under of stream or at lake banks, depressed logs, shakesor even rocks. While others would discover openings in banks, and others makethe gaps themselves. The spawning season will come in the spring or late-springfrom May to June.
They are able to spawn eggs around 5000 up to 10000 eggswhich depends on their age and size. While for their sex, it can be seen anapparent sex ratio of the species is extremely high toward females to males. Theyare intraspecific variety in their regenerative nature, especially duringmating conduct, as it has been research inside the neighbourhood populaces inJapan (Maehata, 2007).
In Japan, a pastinvestigation of the Japanese catfish in almost various lake has indicates a diversemating conduct. For instances, in the lake Biwa populaces it had demonstrated asettled succession of activities, for example the pursuing, the sticking, theenclosing with pressing by the male, and by hovering of the matched fish, andthe females are constantly enveloped by a solitary male (Maehata, 2002), whileat the Ooi lake and at the Fuefuki lake, the populations does not demonstratesuch the same behavioural sequence which was the process of enfolding afemale’s body by a male. The circling by the paired fish has also not been seenbut 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 believedto be aimed at reducing the number of juvenile mortality rate (Katano et al., 1988). The male is generally theall-time caretaker and defender of the eggs. As the fry continue to growto adulthood, their diet will begin to increases as many type of animals suchas the crustaceans, the clams and also small fish become their food (Katano et al.
, 1988). In almost all the maturedadult fish are active and feed during night time. However, this fish also feedin condition such as cloudy and also in opaque waters during sunlight isavailable. The hunting method relies upon their sense of scent and taste due tothe catfish having very poor vision (Maehata, 2007). When the larvae had agedto juvenile and become matured, they will then began to form schools and movetogether.
Moreover, they do not possessany migrating characteristic such as travelling downstream and upstream river. But will spend a lot of their lives in lakes bottom, the reservoirsand river streams. 2.3 African catfish The African catfish is a prevailingfreshwater 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 to59kgs (Freyhof, 2016).
For its characteristic, the body colouration canfluctuates from olive green, to darker and dark with the flanks frequentlyuniform 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 mottledunpredictably with dull tanish green, or consistently gleaming olive.It is heavy bone with a levelheaded and obtaining premaxilla while having lower jaw pointed teeth organisedin few lines. Meanwhile, it also hasfour pairs of long trailing sensory organs known as barbels around its mouth(A-Z animals, 2008). In addition, the catfish has a high number of gill rakersdiffering from 24 to 110.
The number will increase with the size of the fish. These fish are an insatiablepredator and will likely eat almost everything in its sight (Ataguba et al., 2012). Their prey also includesseveral organism such as the insects, the crabs, the plankton, the snails, smallfish, small birds, and many more (Ibrahem, 2011).
It is generally an individualbottom feeder, however they are known to be to a great degree versatile toconditions and can move in groups at the water surface. Meanwhile, it can additionallyshows an assortment of strongly behaviour such as sucking the surface forearthbound creepy crawlies and also someplant pieces that was washed into thewater by overwhelming rains and pack-hunting of small cichlids. The growth is generallyrapid, where the fish can obtain their maximum size within a couple of years(FAO, 2008).
African catfish are generally conveyed far and widearound the world. The species can extend from South Africa up to Middle, Westand North Africa. It is likewise had been dispersed around different continentsuch as the Middle East and Eastern Europe. Furthermore, they are alsoadditionally similarly introduce in Jordan, Lebanon, Israel and Turkey. It hasalso been brought into most of the different nations in Africa, and also a fewin Europe, Asia and South America. Similarly to some other species, China also introduced itwithin its rice-fields and is currently holding the position of among the main producingcountries (De Silva, 2010).
The pattern for African catfish culture has beenincrease throughout the following years since it introduction as one of thebiggest fish species in aquaculture. Even in the market for African catfish inthe sub-Saharan Africa has been increasing and evolving each year (FAO, 2010).2.4 Aquaculture production of catfish By and large, all of the catfishesaround the globe has affected the global economy as they have esteem and arealways gathered as human utilization, pet exchanging and recreations. Theoverall catch record of the freshwater and marine catfishes in 2000 has alreadysurpassed 500,000 metric tons (FAO, 2000). In addition, a few catfishes such asthe Flathead catfish in North America and also the Goliath catfish in SouthAmerica are being forcefully looked for angler in the angling sport (FAO,2000).
In contrary, a numerous number of catfish has been translocated andacquaint with the new zones which makes some of the generous monetarymisfortune and could also harm common environments and local fish abundancy (Schmitt,2016). There is significant catfish pests in North America which is the walkingcatfish, C. batrachus, in Florida, and while also the Flatheadcatfish, Pylodictis olivaris, in the Atlantic slope drainages(Fuller et al.
, 1999).While in Asia and thePacific, the family Clariidae (Clariasspp.) had dominated the aquacultureproduction, by being up to the 80% of the total 76,000 tons catfish which produced in 1991 (FAO, 2000). The mostcultured species were C. batrachus, C. macro-cephalus and C. gariepinus. While the African catfishwas the only introduced species that had an important effect on the Asianaquaculture industry (FAO, 2010).
The first introduction was done in Vietnam ofthe 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 interestingamong the fish farming business. While for the Japanese catfish, In general, itis rapidly gaining high popularity in aquaculture industries mostly in Asianregion. 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 ofrivers where they are harvested throughout year.
Furthermore, the Japanese catfish is also aknown sport fish due to its aggressiveness and powerful body. Generally, fishsport person love catfish as one of the best freshwater fishing game in theworld.2.5 Growth performance of catfish The development of a fish can becharacterized as an increased in magnitude, it can also be estimated by theirsize and also the tissue piece. It speaks to a standout amongst the mostnoteworthy parameters in aquaculture (Silva etal., 2015). Growth isestimated by the units of the length and the weight and is best spoken to asthe important development rate. The main relationship between the weight andthe length can provides an index of the state of well-being of a fish.
The conditionfactor ‘K’Fishes can display a ‘determinate’ which is a sort of development inbrief types of hotter areas and an ‘indeterminate’ sort of extensive types ofcolder districts (Dutta, 1994). It could also be measured by using othercriteria such as the glycine uptake by scales, the hepatosomatic index, the RNA:DNAratio and also the protein retention in the tissues. The nutrition whichincludes the quality and quantity of food, will play an important role ingrowth regulation (Siddiqui, 2014). A few number ofenvironmental factors, such as the temperature, the oxygen concentration, the salinityand the photoperiod, can also affect the rate of growth (Tang et al., 2008). There are fish that canexhibit a determinate type of growth in short-lived species of warmer regionsand an indeterminate type in long-lived species of colder regions (Dutta,1994). The water temperature is a standout amongst the most critical physicalvariables influencing fish development and creation.
Fish are cold bloodedcreatures which expect around an indistinguishable temperature from theirenvironment (Viadero, 2005).The growth performance of theAfrican catfish can be affected by many factors such as stocking density, feedformulation and water quality. Past studies of Micha (1976) suggest that thegrowth 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 some detrimentaleffects on fish welfare based on juvenile African catfish of 10-100g. Factorssuch as feed can affects the growth of African catfish by the number of proteinlevel contain in the feed. High level of protein is very essential to thegrowth of fish but an optimum level is known to ensure 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 hasless information regarding nutrients that can help its growth but past studiesof Cong Liu (2012) states that the dietary protein of 43% and dietary lipidof7% had no significant growth on Japanese catfish compared to S.
meridionaliswhich had shown better growth performance in the same dietary nutrient.However, the Japanese catfish optimum level of dietary protein is 45% formaximum development (Kim et al., 2014).Sex of the Japanese catfish also influences its growth performance as femalegrow much faster than male (Kim et al.,2001). This is due to reaching sexual maturity has reduce its growth rate andreduce its feed efficiency for male.