Posted on 7th Oct 2024 01:08:29 AM Fisheries
INTRODUCTION
The morphometric study of fishes is becoming prominent all over the world to fulfill the lacuna of the knowledge on biological aspects of fishes. Therefore, fisheries biologists are turning their eyes to these aspects from various points of view. Length-weight relationships for fish have been used extensively to provide information on the condition of fish, their isometric or allometric growth, in the analysis of ontogenic changes, to compare life histories of fish species between regions as well as other aspects of fish population dynamics. In fisheries biology, length-weight relationships are useful for the conversion of growth-in-length equations of growth-in-weight for use in stock assessment models and to estimate stock biomass from limited sample sizes (Binohlan and Pauly, 1998; Koutrakis and Tsikliras, 2003; Ecoutin et al., 2005).
The length weight relationship (LWR) of fishes in a given geographic zone in important in fisheries biology because it allows estimation of the average weight at a given length. LWR parameters can also be used as indices of fish condition for life-history comparisons of different regions (Petrakis and Stergiou, 1995; Thomas et al., 2003) as well as other applications in population dynamics as revised by Mendes et al. (2004).
Length-weight relationships for fish were originally used to provide information on the condition of fish and to determine whether somatic growth was isometric or allometric (Le Cren, 1951; Ricker, 1975). All living animals have a tendency to maintain symmetrical growth of its different body parts in relation to one another. It is generally known that all the body parts are dependent on the total length of the body i.e. growth of the body parts are proportional to the growth of the total length. But the total length of the body is not dependent on all other body parts. So, morphometric measurements of fishes and the study of statistical relationship among them are essential for taxonomic study of a species (Tandon et al. 1993).
Morphomeristic character is the character based on measurement. In fish, measurements are taken on a straight line basis, not around the curve of body with the exception of such measurements specifically intended to measure roundness, e.g. girth. Any measurements should be defined or referenced to a standard work as some may include soft parts or only be from bony margin to bony margin. Some measurements include total length (TL), standard length (SL), heal length (HL) etc.
According to Vladykov (1934) morphometric and meristic characters of fishes can be divided into three categories. The first category includes those characters which have very low ranges of body proportions and are genetically controlled. The second includes those having wide ranges of proportions and showing impact of the hydrological conditions. The third is the intermediate category which includes those characters partly controlled by the environment. Vladykov (1934) further classified the characters into two categories. Some characters show wide rage and thus can be controlled by the environment; others show narrow range and are said to be controlled genetically. In recent years the significance of the statistical relationship of the morphometric characters has also been recognized in all taxonomic and systematic studies.
Growth of fish may be described in terms of changes in length, width or any other linear dimensions as well as by weight (King, 1995). In fish studies, fish length is often more rapidly and easily measured than mass. Thus knowing the length-weight relationship makes it more convenient to determine mass where only the length is known (Froese and Pauly, 1998). The length-weight relationship is an important tool in fish biology, physiology, ecology and fisheries assessment (Oscoz et al., 2005). Length-weight relationships for fish have been used extensively to provide information on the condition of fish, their isometric or algometric growth, in the analysis of ontogenic, to compare life histories of fish species between regions as well as other aspects of fish population dynamics. In fisheries biology, length-weight relationships are useful for the conversion of growth-in-length equations to growth-in-weight for use in stock assessment models and to estimate stock biomass for limited sample sizes (Binohlan and Pauly, 1998; Koutrakis and Tsikliras, 2003; Valle et al., 2003; Ecoutin et al., 2005).
The length –weight relationship and population dynamics of fishes are studied with the major objectives of rational management and resource conservation (Nasser, 1999). Length-weight relationships are needed to estimate weight from length because direct weight measurements can be time consuming in the field (Sinoveic et al., 2004) and its parameters are important in fish biology and can give information on stock condtion (Tesch, 1978, Hossain et al., 2006).
Therefore, the application of length-weight relationship in fishery biology solves various problems concerned with the life history of fishes. Besides providing a mathematical relationship between length and weight of fish as a means of introversion, such a relationship also yields information on the general well being of the fish, variation in growth, size at first maturity, gonad development and breeding season (Chatterji et al., 1977), and seasonal changes in their specific gravity (Tester, 1940).
Condition factors may be used to detect seasonal variations in the condition of fish, which may vary with food abundance, and average reproductive stage of the stock (King, 1995). It is a numerical index by which weight and length in particular samples are usually compared under standard conditions (Ricker, 1975).
On the other hand, condition factor is a quantitative parameter of the state of well being of the fish that will determine present and future population success by its influence on growth, reproduction and survival (Hossain et al., 2006). The condition of a fish reflects recent physical and biological circumstances and fluctuates by interaction among feeding conditions, parasitic infection and physiological factors (LeCren, 1951)
The length-weight relationship of fish is an important fishery management tool. Its importance is pronounced in estimating the average weight at a given length group (Beyer, 1987) and in assessing the relative well being of a fish population (Bolger and Connoly, 1989). The study of length-weight relationship has its applied value in fish biology. These studies are also widely used in stock assessment models and estimation of biomass from length observation (Weatherly and Gill, 1987; Wootton, 1990; Moutopoulos and Sleryion, 2002). Length-weight relationships also give information on the condition and growth patterns of fish (Bagenal and Tesch, 1978).
The length-weight relationship is also a useful tool for fish culturists. When large numbers of fishes must be individually sampled, it is faster and often more convenient to determine the fish length rather than weight (Steeby et al., 1991). This relationship is also used in commercial sales and population assessment (Steeby, 1995). According to Le Cren (1951) and Tandon (1961) the length-weight relationship is helpful in the determination of spawning season, onset of sexual maturity etc. The application of length-weight relationship in fishery biology solves various problems concerned with the life history of fishes. Besides providing a mathematical relationship between length and weight of fish as a means of introversion, such a relationship also yields information on the general well-being of the fish, variation in growth, size at first maturity, gonadal development and breeding season (Chatterji et al., 1977), and seasonal changes in their specific gravity (Tester, 1940).
The exact relationship between length and weight differs among species of fish according to their inherited body shape and within a species according to the condition (robustness) of individual fish.
Study of body measurements have been extensively used in the identification of the species of fishes. In recent years the significance of the statistical relationship has also been recognized in all taxonomic and systematic studies.
Condition factor is a quantitative parameter of the state of well-being of the fish that will determine present and future population success by its influence on growth, reproduction and survival (Hossain et al., 2006). The condition of a fish reflects recent physical and biological circumstances, and fluctuates by interaction among feeding conditions, parasitic infections and physiological factors (Le Cren, 1951). It is a numerical index by which weight and length in a particular sample are usually compared under standard conditions. Condition factors may be used to detect seasonal variations in the condition of fish, which may vary with food abundance and the average reproductive stage of the stock (King, 2007).
Fisheries sector also made a significant contribution to the process of improving food security through the opportunities the sector provides for employment and income of people either directly on indirectly. This sector provides income for about 1.5 million full time professional fishermen, i.e., 5% of national lobour force. In addition there are about 12 million peoples whose livelihood depends indirectly on fisheries (DoF, 2011). The income from employment and the financial revenues from the sale of fish, provide cash which can then be used for further income. According to the statistics of 2009-10, fisheries sector contributes about 3.74% to the total GDP and 2.70% to the country total export earning. This sector accounts about 28.99% of country total agricultural income (DoF, 2011).
Poor people in developing countries like Bangladesh tend to depend essentially on carbohydrate based diets for their nutritional intake. These are however, relatively low in protein and micronutrients. In this context, fish can play a particularly important role in combating micronutrient deficiencies, as they contain high quality protein, essential fatty acids and also key micronutrients such as vitamin A, calcium, zinc and iodine. According to nutritionist 45 g protein is needed per capita per day. One third of this or 15 g should be animal protein. About 58% animal proteins are met by fish as an available and cheap source of protein and for this we need to eat about 56 g fish daily.
Bangladesh is blessed with an abundance of inland water bodies filled with a diversity of indigenous fish species and the majority of these fish species are small indigenous species (SIS) of fish. Small indigenous species (SIS) of fish have been defined as species which grow to a maximum length of about 25 cm (Felts et al., 1996). However many SIS are less than 10 cm long and they are typically eaten whole with organ and bones. There are 265 fresh water species at present in our country in which about 143 species are SIS (Felts et al., 1996). But about 50 species of small indigenous species are available in closed water bodies of Bangladesh. Among these about 20 species are carp fish and about 10 species are cat fish type (Hoq, 2006). These are important target species for small scale fisher in Bangladesh, who uses a variety of traditional fishing gears (Kibria and Ahmed, 2005).
JUSTIFICATION OF SPECIES SELECTION
Small indigenous fish species have high nutritional value in terms of micro-nutrient, vitamins and mineral contents which are not commonly available in other food. Since these species are normally cooked and eaten whole, their effects on the diet are further enhanced since the bones also provide rich source of calcium. Some of the small indigenous fish species such as Punti (Puntius sophore), Khalisha (Calisa fasciatus), Bele (Glossogobius giuris), Taki (Channa punctatus), Tengra (Mystus cavasius), Gutum(Lapidocephalus guntea), Guchi (Mastasembelus pancalus), shing (Heteropneustes fossilis) and darkina (Esomus danricus) contain more available vitamin-A than any other edible freshwater fish of Bangladesh (Thilsted etal., 1997).
As per fulfilment of the biological need to these species, the study on the morphometric characters is essential. So, the present study is aimed to know the morphometry and growth performance of Channa punctatus, Esomus danricus, Puntius sophore, Lepidocephalus guntea, Mystus cavasius, Heteropneustes fossilis, Glossogobius giuris, Colisa fasciatus and Mastacembelus pancalus etc.
OBJECTIVES OF THE STUDY
The objectives of the study are-
· to study the length-length relationship among different morphological characters of the specimens,
· to study the length-weight relationship of the specimens,
· to study the condition factors to observe the growth of the specimens, and
· to assess the habitat profile of the specimens depending on their morphological characters.
PROFILE OF THE SPECIMENS
The profile features of the nine specimens are made according to Encyclopedia of Flora and Fauna of Bangladesh (Siddique et al. 2007).
Glossogobius giuris (Hamilton, 1822)
Systematic position:
Phylum: Chordata
Class: Osteichthyes
Order: Perciformes
Family: Gobiidae
Genus: Glossogobius
Species: G. giuris
English names: Tank Goby, Bar-eyed Goby
Local names: Bele, Bailla
Synonyms:
Gobius giuris Hamilton, 1822, Fishes of the Ganges, p. 51;
Gobius kokius Valenciennes, 1837, Hist, Nat, Poiss. 17: 68;
Gobius russellii Valenciennes, 1837, Hist, Nat, Poiss., p. 75;
Gobius phaiosoma Bleeker, 1849, Verh, Bat, Gen, 22: 30;
Gobius sublitus Cantor, 1850, J. Asiat. Soc. Bengal 18: 163;
Gobius unicolour Günter, 1861, Cat. Fish. Brit. Mus. 3: 23;
Glossogobius giuris Hora, 1923, J. Siam. Soc. Nat. Hist. 6: 143-184.
Description:
Body elongated, anteriorly cylindrical, posteriorly compressed. Head pointed, depressed, lower jaw longer. Lips thick. Teeth villiform in the jaws, outer and inner rows enlarged, caninoid in front in both the jaws. Tongue bilobed. Dorsal fins close together. Pelvic fins inserted in the thoracic region, forming an adhesive disc. Caudal pointed or somewhat rounded (Rahman, 1989).
Habits and habitats: The fish is predatory and burrowing in nature and it is reported to live inside soil holes on the bed of water bodies. Primarily inhibits rivers, canals, beels, ditches and similar freshwater bodies; it also lives in estuaries and seas.
Distribution: Indo-West Pacific, Bangladesh, India, Thailand, Myanmar, the Philippines, Indo-China, Africa, Australia and the East Indies. The fish is widely known for its worldwide distribution.
Economic importance: In Bangladesh as in various other tropical and subtropical countries, the size, abundance, and food value of G. giuris give the species considerable economic importance.
Esomus danricus (Hamilton, 1822)
Systematic position:
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Cypriniformes
Family: Cyprinidae
Genus: Esomus
Species: E. danricus
English Name: Flying Barb
Local names: Darkina, Danrika, Darka, Dadhika
Synonyms:
Cyprinus danrica Hamilton, 1822, Fishes of the Gunges, pp. 325, 390;
Cyprinus jogia Hamilton, 1822, Fishes of the Ganges, pp. 326, 391; Esomus danrica Bleeker, 1863, Atl. Lchth. Cypr. 3: 32; Nuria danrica Day, 1875, Fishes of India, p. 583; Esomus danricus Shaw and Shebbeare, 1937, Fishes of Northern Bengal, p. 29.
Description:
Laterally compressed body, mouth small, directed obliquely upwards with a fleshy lower lip. A distinct concavity over the nape in some. Barbel 2 pairs, rostral pair extending to the angle of the preopercle, maxillary pair longer, reaching beyond the pelvics. Lower jaw longer. Dorsal fin placed in the posterior half of the body. Anal origin below posterior base of the dorsal.Pelvics equidistant from the snout tip and the caudal base. Margin of the scales of the upper half of the body dotted. Yellowish-white beneath (Rahman, 2005).
Habits and habitats:
Benthopelagic, potamodromous, It has the habit of jumping above the water surface. Caught with other minnows in ditches, ponds and beels during the dry season. Found in small streams, ponds, weedy ditches, beels and inundated fields. Abundant during the rainy season.
Distribution:
Bangladesh, India, Pakistan, Nepal, Afghanistan, Sri Lanka and Myanmar.
Economic importance:
Small Indigenous Species (SIS) and found abundantly in rural Bangladesh. There is a great demand in local people. It is one of the cheap sources of protein and other essential elements (Rahman, 2005).
Mastacembelus pancalus (Hamilton, 1822)
Systematic position:
Kingdom: Animalia (animals)
Phylum: Chordata (chordates)
Subphylum: Vertebrata (vertebrates)
Class: Actinopterygii
Order: Synbranchiformes
Family: Mastacembelidae (Spiny eels)
Genus: Mastacembelus
Species: M. pancalus
Local names: Guchi, Pankal, Turi, Chirka.
English name: Striped spiny Eel
Synonyms:
Macrognathus pancalus Hamilton 1822, Fishes of the Ganges, p. 30;
Mastacembetus panctatus Cuvier and Valenciennes,1832. Hist. Nat. Poiss. 8:463.
Mastacembelus pancalus Day 1876, Fishes of India, p. 340.
Description:
Body eel-like, elongated and slightly compressed, tooth plates. Preopercle with 2-5 spines, mouth small. Lateral line complete. Scales cycloid and minute. Dorsal fin inserted above the middle of the pectoral fins’ dorsal and anal fins separated from the caudal fin. Greenish-olive along the back, yellowish on the belly, with many yellowish-white spots on the flanks and often with dark brown vertical stripes in the posterior half of the body. Soft dorsal, anal, pectoral and caudal fins yellow, with numerous minute black spots.
Habits and habitats:
Mostly debris-feeders. The species likes to hide in the bottom mud. Small rivers, canals, streams, beels, ponds and inundated fields are suitable habitats. Very abundant during the rainy season (Rahman, 1989).
Distribution:
Pakistan, India, Sri Lanka, Nepal, Myanmar, through Thailand and Malaysia to south China. Distributed in rivers, canals, beels, ponds and inundated field throughout Bangladesh (Rahman, 1989).
Economic importance:
M. armatus is the Spiny Eel in Bangladesh has considerable commercial value. It is tasty fish and the live ones fetch a good price.
Lepidocephalus guntea (Hamilton, 1822)
Systematic position:
Phylum: Chordata
Class: Actinopterygii (Ray-finned fishes)
Order: Cypriniformes (Carps)
Family: Cobitidae (Loaches)
Genus: Lepidocephalus
Species: L. guntea
English names: Peppered Loach, Guntea Loach
Local names: Gutum, Puiya
Synonyms:
Cobitis guntea Hamilton, 1822, Fishes of the Ganges, p. 353;
Cobitis balgara Hamilton, 1822, Fishes of the Ganges, p. 356;
Lepidocephalichthys guntea Day, 1878, Fishes of India, p. 609;
Lepidocephalus guntea birmanicus Banarescu and Nalbant, 1968, Mitt, Hamburg Zool. Mus. Inst. 65: 345;
Lepidocephalus (Lepidophalichthys) guntea Tilak and Hussain, 1981, Occ. Paper, Rec, Zool. Surv, India 32: 7.
Description:
Body compressed. Dorsal and ventral profile nearly parallel; body deepest near the origin of the dorsal. Barbel 3 pairs, 2 rostral and 1 maxillary pairs; mandibular flaps with barbels. Caudal rounded. Lateral line absent. A light band extends from the snout to the caudal fin. Dorsal and caudal barred with spots. Attains a length of about 15 cm. Largest specimen examined was 9.6 cm in total length (Rahman, 2005).
Habits and habitats:
Demersal; potamodromous; fresh and brackish water. Feeds on insect larvae and bottom detritus. In the streams of Mymensingh, Sylhet, Dinajpur and Rangpur. Also in swamps and beels throught Bangladesh (Talwar and Jhingran, 1991; Menon, 1999; Rahman, 2005).
Distribution:
Pakistan, northern India, Bangladesh, Nepal, Myanmar and Thailand.
Economic importance:
Of no interest to fisheries but of interest as an aquarium fish. The fish is found is small quantities in markets.
Colisa fasciatus (Bloch and Schneider, 1801)
Systematic position:
Kingdom : Animalia
Phylum : Chordata
Class : Actinopterygii
Subclass : Neopterygii
Order : Perciformes
Suborder : Anabantoidei
Family : Osphronemidae
Genus : Colisa
Species : fasciatus
English names: Stripled Gourami. Giant Gourami.
Local names: Khailsha, Khoila, Cheli, Khoira.
Synonyms:
Trichogaster fasciatus Bloch and Schneider, 1801, Syst. Ichth., p. 164; Trichopodus calisa Hamilton, 1822, Fishes of the Ganges, p. 117;
Trichopodus bejens Hamilton, 1822, Fishes of the Ganges, p. 118;
Trichopodus cotra Hamilton, 1822, Fishes of the Ganges, p. 119;
Colisa fasciata Sterba, 1962, Freshwater Fishes of the World. p. 787.
Description:
Dorsal and abdominal profile equally convex. Mouth small, directed obliquely upward. Lower margin of the preorbital with 9-14 denticulations. The lips are thick with papillae. Soft dorsal mostly pointed. Pelvic consist of a single filiform ray extending to the caudal. Caudal usually cut square of very indistinctly notched, may be rounded in some. Lateral line interrupted.
Habits and habitats:
An omnivore, prefers to feed on insect larve living among dense aquatic vegetation of shallow waters. Found to inhabit transparent, shallow stagnant waters, including ponds, ditches, canals, rice fields, beels, baors and flood plains. Abundant in beels.
Distribution:
Found to occur in all kinds of freshwaters throughout Bangladesh, India, Pakistan, Nepal and Myanmar.
Economic importance:
This fish is highly esteemed as food, and liked by all for its good taste and because it can be eaten bones and all. An important source of protein, iron and riboflavin.
Puntius sophore(Hamilton, 1822)
Systematic position:
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Superclass: Gnathostomata
Class: Actinopterygii
Subclass: Neopterygii
Superorder: Ostariophysi
Order: Cypriniformes
Family: Cyprinidae
Genus: Puntius
Species: P. sophore
English name: Spotfin Swamp Barb, Pool Barb
Local name: Punti, Jat Punti
Synonyms: Cyprinus sophore Hamilton, 1822, Fishes of the Ganges, pp. 310, 389; Systomus sophore McClelland, 1839, Asiat, Res, 19:285: Barbus sophore Gunther, 1868, Cat, Fish, Brit, Mus. 7: 152; Barbus annandalei Folwer, 1924, Proc, Acad, nat. Sci. Phil. 76:87; Puntius sophore Chauhan and Ramakrishna, 1953, Rec. Indian Mus. 51: 405.
Description:
Body moderately compressed, dorsal profile more convex than that of the abdomen. Head short, about one-fourth the standard length (Talwar and Jhingran, 1991). Mouth shall, terminal; upper jaw slightly longer. Barbel absent. Last unbranched ray of the dorsal osseous, smooth. Silvery with a round dark spot at the base of the dorsal rays and another at the tip of the tail on the 23rd to 25th scales of the lateral line. A scarlet red band develops along the middle of either side in males during the breeding season. Less distinct in females (Rahman, 2005).
Habits and habits:
Voracious eaters of floating organisms and aquatic plants. Can breed everywhere in its habitat during the rainy season. They inhabit rivers, streams, ponds and paddy fields.
Distribution:
Bangladesh, Pakistan, India, Nepal, Bhutan, Myanmar and China (Talwar and Jhingran, 1991).
Economic importance:
The puntiid fishes are the most numerous as to the speices and among the most abundant as to the individuals among the freshwater fishes of Bangladesh. It is considered of medicinal value in Tamil Nadu, India (Talwar and Jhingran, 1991).
Heteropneustes fossilis (Bloch, 1974)
Systematic position:
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Siluriformes
Family: Heteropneustidae
Genus: Heteropneustes
Species: H. fossilis
English Name: Stinging Catfish, Fossil Catfish, Liver Catfish.
Local Names: Shing, Jiol, Shinghi, Jill Shinghi
Synonyms:
Silurus fossilis Bloch, 1974, Hist, Nat, Poiss, 44: 36;
Silurus singio Hamilton, 1822, Fishes of the Ganges, p. 147;
Saccobranchus fossilis Valenciennes, 1840. Hist, Nat, Poiss. 15: 400; Saccobranchus fossilis Day, 1878, Fishes of India, p. 486;
Heteropneustes fossilis Misra, 1976, Fauna of India, Pisces (2nd ed.). 3: 135.
Description:
Body elongate, subcylindrical up to the pelvic fin base, compressed behind. Head depressed with the top and sides covered with osseous peats, occipital process not extending to the base of the dorsal fin. Mouth small and terminal. Barbel 4 pairs, well-developed. Dorsal fin short. Pectoral fin with a strong spine. Anal fin long-based, separated by a distinct notch from the caudal fin, the latter rounded.
Habits and habitats:
Demersal, omnivorous and a predator. Lives in large shoals near the bottom. Primary habitats are ponds, ditches, beels, swamps and marshes, also occurs in muddy rivers. Its air breathing apparatus enables it to exist in almost any kind of water.
Distribution:
Widely distributed in lentic freshwaters and rearely in brackish waters through Bangladesh, India, Pakistan, Nepal, Sri Lanka, Myanmar, Thailand and Laos.
Economic importance:
A fish of high economic importance. The fish is in great demand because of its medicinal value (Talwar and Jhingran, 1991) and esteemed as food for the convalescents (Bhuiya, 1969).
Channa punctatus (Bloch, 1793)
Systematic position:
Kingdom: Animalia
Phylum: Chordata
Class: Osteichthyes
Order: Perciformes
Sub-order: Channoidei
Family: Channidae
Genus: Channa (Scopoli)
Species: C. punctatus (Bloch)
English Name: Spotted Snakehead
Local names: Taki, Lata, Lati, Okol, Chaitan
Synonyms:
Ophiocephalus punctatus Bloch, 1793. Natur. Aus. Fische 7: 139; Ophiocephalus karrouveri Lacepede, 1802. Hist, Nat, Poiss, 3: 552: Ophiocephalus lata Hamilton, 1822. Fishes of the Ganges, pp. 63, 367; Ophiocephalus indicus McClelland, 1842, Calcutta J. Nat. Hist, 2:583;
Channa punctatus Menon, 1954, Rec. Indian Mus, 52: 22.
Description:
Body almost cylindrical anteriorly, laterally compressed posteriorly. Anterior nasal opening produced into a tubular process. Cephalic pits simple, lage plate-like scales on the head. Mouth moderately cleft, maxilla extends to the hind edge of the orbit. Teeth villiform on the jaws. Pelvic fin thoracic, caudal rounded. Scales 40-41 on the lateral line; Scales on the sides in some specimens with small black spots (Rahman, 2005).
Habits and habitats:
Great predators (Rahman, 1989). Oviparous: carnivorous: solitary or in pairs, highly gregarious when young. Young (1.5-3.0 cm) feed primarily on zooplankton. With rotifers, insects and crustacean larvae constituting most of the diet.The preferred habitat is ponds with a swampy bottom,ditches,beel and abundant aquatic vegetation, as well as ponds with sand or gravel substrate and no vegetation.
Distribution:
Widely distributed in India. Bangladesh and Sri Lanka.
Economic importance:
This species is regarded as important fishery resources in Bangladesh and elsewhere. Fished commercially, popular as food and is also used as a bait for catching larger snakeheads.
Mystus cavasius (Hamilton, 1822)
Systematic position:
Phylum: Chordata
Class: Actinopterygii (Ray-finned fishes)
Order: Siluriformes (Catfishes)
Family: Bagridae (Bagrid catfishes)
Genus: Mystus
Species: M. cavasius
English name: Gangetic Mystus
Local names: Kabashi Tengra, Gulsha Tengra
Synonyms:
Pimelodus cavasius Hamilton, 1822, Fishes of the Ganges, p. 203;
Pimelodus seengfee Sykes, 1841, Trans. Zool. Soc. Land. 2: 374;
Hypselobagrus macronema Bleeker, 1865, Ned, Tijds, Dierk, 2: 175;
Aoria cavasius Prashad and Mukerjii, 1929, Rec., Ind. Mus. 9: 39;
Mystus cavasius Shaw and Shebbeare, 1937, Fishes of Northern Bengal, p. 91.
Description:
Body elongated and compressed, depth about one-fourth of the standard length. First ray of dorsal much longer than head.Head conical.Mouth terminal. Barbel 4 pairs. Pectoral spine with 11-12 deniticulation. Adipose fin large, inserted. Caudal fin deeply forked. A black spot is present covering the basal bone of the dorsal fin.
Habits and habitats:
Feeds on insect larvae, zooplankton and small fish. Prefers tidal rivers and lakes; also beels canals, ditches, ponds and inundated fields.
Distribution:
Pakistan, India, Nepal, Sri Lanka, Bangladesh, Myanmar and Thailand.
Economic Importance:
Kabashi Tengra is a commercially important species and a common food fish in Bangladesh. It has potential as a aquarium fish as well.
ABSTRACT
The morphometric study of nine freshwater small indigenous species (SIS) viz. Glossogobius giuris, Esomus danricus, Mastacembelus pancalus, Lepidocephalus guntea, Colisa faciatus, Puntius sophore, Heteropneustes fossilis, Channa punctatus, and Mystus cavasius was carried out. A total of 540 specimens (each of 60) were observed to find out the morphometric status. The length-length relationships of the species were calculated and the equations were found statistically significant with all “r” values being >0.900. The relationships between total length and weight of the specimens were also observed. The obtained equations of nine specimens were TW = 0.017466 TL3.0111 for G. giuris, TW = 0.050511 TL2.8121 for E. danricus, TW = 0.05934 TL2.8520 for M. pancalus, TW = 0.00833 TL2.8401 for L. guntea, TW = 0.004818 TL3.0301 for C. fasciatus, TW = 0.00138 TL2.9901 for P. sophore, TW = 0.04741 TL2.6802 for H. fossilis, TW = 0.06862 TL2.8401 for C. punctatus and TW = 0.03361 TL2.6501 for M. cavasius. The parameter “b” of the length-weight relationship equation showed higher value (>3) only for G. giuris and C. fasciatus. Rest of the specimens showed lower value (<3) which indicates the poor growth of the specimens. On the other hand the Fulton’s condition factors showed positive growth tendency for five specimens’ viz. G. giuris, C. fasciatus, P. sophore C. punctatus and M. cavasius; and negative tendency for the rest. Result of these two parameters pursuing the generalized poor environmental condition of the fishs’ habitat. Findings of the research work will help in the proper management of the specimen as well as all fishes of the study area.
CONTENTS
Acknowledgement
Abstract
Contents
List of tables
List of plates
List of figure
CHAPTER ONE: INTRODUCTION
Justification of species selection
Objectives of the study
Profile of the specimens
CHAPTER-TWO: REVIEW OF LITERATURE
CHAPTER-THREE: MATERIALS AND METHODS
Description of sampling area
Selection of the species
Collections of species
Preservation
Measurements
Determination of Length-Length Relationships
Determination of length-weight relationship
Determination of Condition factor
Statistical analysis
CHAPTER FOUR: RESULTS AND OBSERVATIONS
Length -length (LL) relationships
Total length (TL) and standard length (SL) relationships
Total length (TL) and dorsal length (DL) relationships
Total length (TL) and pectoral length (PL) relationships
Total length (TL) and pelvic length (PvL) relationships
Total length (TL) and anal length (AL) relationships
Total length (TL) and head length (HL) relationships
Length-weight relationships and Fulton’s condition factor
CHAPTER FIVE: DISCUSSION
Relationship between total length with different body length
Length weight relationship
Condition factor
CHAPTER SIX: CONCLUSION
References
LIST OF TABLES
1. Relationships between total length-standard length of nine specimens (SL= a+bTL)
2. Relationships between total length-dorsal length of nine specimens (DL= a+bTL)
3. Relationships between total length-pectoral length of nine specimens (PL= a+bTL)
4. Relationships between total length-pelvic length of nine specimens (PvL= a+bTL)
5. Relationships between total length-anal length of nine specimens (AL= a+bTL)
6. Relationships between total length-head length of nine specimens (HL= a+bTL)
7. Length-weight relationship and Fulton’s condition factor
LIST OF FIGURES
1. Map of Nageswari Upazila showing studied waterbodies
2. Layout of a representative fish showing different morphometric measurements
3. Relationship between total length and standard length of nine specimens
4. Relationship between total length and dorsal length of nine specimens
5. Relationship between total length and pectoral length of nine specimens
6. Relationship between total length and pelvic length of nine specimens
7. Relationship between total length and anal length of nine specimens
8. Relationship between total length and head length of nine specimens
9. Length-weight relationship for G. giuris
10. Length-weight relationship for E. danricus
11. Length-weight relationship for M. pancalus
12. Length-weight relationship for L. guntea
13. Length-weight relationship for C. fasciatus
14. Length-weight relationship for P. sophore
15. Length-weight relationship for H. fossilis
16. Length-weight relationship for C. punctatus
17. Length-weight relationship for M. cavasius
LIST OF PLATES
1. Glossogobius giuris
2. Esomus danricus
3. Mastacembelus pancalus
4. Lepidocephalus guntea
5. Colisa faciatus
6. Puntius sophore
7. Heteropneustes fossilis
8. Channa punctatus
9. Mystus cavasius
10. Showing the weighting of the species
11. Showing the measurement of different body length of the species
Thesis, Study, Morphometric, Characters, Freshwater, Water, Bodies, Nageshwari, Kurigram, Bangladesh, Punti, Khalisha, Bele, Taki, Tengra, Gutum, Guchi, Shing, Darkina, Fish, Vitamin-A, Glossogobius, Giuris, Esomus, Danricus, Mastacembelus, Pancalus, Lepidocephalus, Guntea, Colisa, Faciatus, Puntius, Sophore, Heteropneustes
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