Indian and exotic major carps fishes

 

Indian Major Carps

Catla catla :- It is the fastest growing carp identified by deep body depth, larger head, wider upturned mouth and prominent lower jaw. More convex dorsal region looks blackish grey and belly is silvery in colour. Dorsal profile is more convex than abdomen.  Dorsal fin is equipped with 14-16 branched fin rays and it commences slightly before the ventral fin. Anal fin extends to the base of caudal fin. Lateral line is complete and scales are prominent. It is a surface feeder fish species that prefer to consume zooplankton. Young fry are planktophagus preferring unicellular algae. Fry of 2.0 cm starts feeding on zooplankton, showing preference for protozoans, crustaceans, rotifers, mollusks and decayed macro vegetation. 

Labeo rohita :- Commonly known as Rohu. Body is elongated having comparatively less depth than Catla catla. Head is small, pointed and with fringed lower lip. One pair of thin maxillary barbels are present. Lateral line is complete and scales are also prominent. Scales are having red colour points in the center. Dorsal profile is more convex than ventral. It is a column feeder fish that inhabit in the middle strata of the pond water. It is a periphyton feeder. Larvae and fry of Rohu feed on unicellular algae and zooplanktonic organisms. Fingerlings feed on vegetable debris and microscopic plants. Adult feeds on various types of organisms preferring periphytons, vegetable organic matter and decaying higher plants. It attains sexual maturity by the end of second year and like Catla it also breeds in running water during mansoon months.

 Cirrhinus mrigala :- Commonly it is known as Nain. It is characterized by its linear body shape, sub-terminal mouth, and bright silvery body having a golden tinge. Eyes are prominent. One pair of short nostril barbels are present. Dorsal profile of body is more convex than ventral region. It is an omnivore bottom feeder and occupies the bottom of the pond. It feeds upon decaying algal, plant decaying organic matter. Sexual maturity is attained by the end of second year. It also does not breed in confined water. Naturally breeding is possible after attainment of sexual maturity of two years and can be induced breed successfully.

Exotic major carps

Exotic major carp fishes have higher growth rate, they are hardy in nature and therefore can survive better. They have been introduced in our country. Silver carp, Grass carp and Common carp are the three main species of carps which contribute second in total fin fish production from freshwater bodies after Indian Major Carps. The exotic carp fishes contribute significantly to the total freshwater fish production. In some water bodies the exotic major carps introduction have also resulted into lower production of some of Indigenous fish species. Common carp introduced in to Kashmir valley has almost exterminated indigenous Schizothorcids. Similarly, Osteobrama belongs to endemic fish to Loktak lake is disappearing rapidly due to Common carp introduction. Therefore the advantage and disadvantage must be studied in prior to introduction of any exotic species.

Hypophthalmichthys molitrix:- Commonly it is known as silver carp because of its shining scales colours like silver. Scales are small and lateral line is complete. Basically it is native of China. In India it was introduced in 1959 from Japan at Cuttack, Orissa. It is characterized by laterally compressed body, upturned mouth and slightly extended lower jaw. Ventral profile is more concave than dorsal. Head is small, snout is rounded and mouth is broad. Lower jaw is slightly protruding. Abdomen is keeled from isthmus to anus. Body scales are small with dark in the dorsal region and silvery below the lateral line. Dorsal fin originates behind the pelvic fin. Pectoral fin reaches up to the pelvic fin. It is surface feeder fish that prefers phytoplankton to consume. Fry and adult feed on flagellate, dianoflagellates, protozoans and rotifers supplemented by decayed macro vegetation and detritus.

Ctenopharyngodon idella:–It is commonly known as grass carp. It is native of Amur river basin therefore also known as white Amur. In India it was transplanted in 1959 at Cuttack, Orissa. It is characterized by elongated, slightly compressed long cylinder body with broad head and short round snout. Mouth is wide and sub terminal. The upper jaw is slightly larger than lower. Barbles are absent.  Dorsal fin is ahead of pelvic fibs. Caudal peduncle is comparatively shorter than other major carps. Body colour is olive at dorsal region while belly is silvery white. Grass carp young fry feed on micro-vegetation and zooplankton. When they attain a size of 2.5 cm they begin to feed on aquatic vegetation like small azolla, lemna and spirogyra. Adult fish feed on soft leaves, weeds and varieties of other aquatic plants.  Partially indigested food in the form of faecal matter work as manure to produce planktons. Grass carp also does not breed in confined water.

 Cyprinus carpio: -It is commonly known as Common carp. The Persian strain of Common carp was introduced in Nilgiri Hills of Tamilnadu in year 1939 from Srilanka. While Chinese starin was transplanted in 1957 from Bangkok. It is characterized by small pointed head and protrucible mouth. Lips are thick that support browsing activity. Paired barbels are small and stumpy. Body is laterally compressed; colour is olive green in dorsal region and yellowish ventrally. It is omnivorous bottom feeder fish. Based on the size and pattern of scale arrangement three varieties of Cyprinus carpio are known C.carpio variety spicularis (Mirror carp) – Few large scales cover the body unevenly and major part of its body remain devoid of scales.C.carpio variety communis (Scale carp) – This fish is having small scale than C. carpio spicularis completely covering the body.

C. carpio variety nudus (Leather carp)- Scales are almost completely absent on the body of leather carp which gives appearance of leathery skin. The fish larvae of common carp are omnivorous in feeding habit and feeds on variety of items. It browses on the shallow bottom also feed on the vegetable debris, insects, worms, crustaceans and planktonic algae. The fish breed almost throughout the year with peak from January to April. It can breed in confined water. The eggs are adhesive and attach to the leaves of submerged plants. In Indian condition Common carp mature during first year of age.

cat fish breeding in Hindi

Aquaculture and major carps fishes

                Aquaculture     

Aquaculture is the fastest growing food sector around the world. It can be defined as " farming of aquatic organism mainly fin fishes, crustaceans, mollusks and seaweeds with some deliberate intentions to interfere in their life cycles".It not only provides the nutritious food to the millions of people but also offers job in main aquaculture and its subsidiary sectors like craft and gear, feed industry, fish processing,fish feed additive, chemicals and drugs and aquaculture sector. It has witnessed spectacular growth and transformed from traditional to semi-intensive and intensive aquaculture practices.  It is practices in freshwater community ponds, rives,lakes, cold water upland lakes, reservoirs, canals, seasonal ponds, swamps, coastal, brackish, marine waters. In freshwater fishes in India Indian Major carps are the main species contributing to more than 80% of total freshwater fish production. Indian major carps (IMC) includes following three species namely

Catla   - Catla catla

Rohu    - Labeo rohita

Mrigal  - Cirrhinus mrigala

    

    IMC are also known as Gangetic carps as they are native to Indian river Ganga.

Exotic major carps species includes

Silver carp   - Hypophtahlmicthys molitrix

Grass carp    - Ctenopharyngodon idella

Common carp   - Cyprinus carpio

   These carps species are cultures in Asian countries like India, Pakistan, Bangladesh, Sri Lanka, Vietnam mainly.  They are fast growing, hardy fish species accepting wide range of feed having consumer demand to fetch good market price. The average per kilogram price of these fishes ranges from Rupees 150-250 kg in India.

Carps: Carps are toothless (absent in mouth but have teeth as pharyngeal ring)  fishes having scales on their body but head. remain devoid of scales.

 Their culture involves various steps like

1.Pre-stocking pond management

2.Stocking pond management

3.Post stocking pond management

Fish fingerlings rearing in pond- 1& 2

          Giant freshwater Prawn  Macrobrachium rosenbergii 
                            3 & 4

                  A view of culture pond 5 &6

Aquatic weeds

 Aquatic vegetation

 

      Weeds are the unwanted plants that interferes the agricultural practices or production. They grow in the pond, river, stream, lakes and any other water body restricting the sunlight, movement of fishes and compete for nutrient, food and space with the cultured species. They also compete for fish eating organisms affecting fish production. Their propagation is very fast through shoot, fragmentation, runners, stolons, root, tubers, corm, bulbs, rhizomes and other diverse form. Knowledge of aquatic weeds their various forms and management is essential for optimum fish production.

 

15.1. Aquatic plant descriptions:-One of the major problems in fish ponds is to control the excessive growth of aquatic weeds. The presence of some aquatic plant in pond to a limited extent is desirable but their excessive growth is very harmful from both pond management and fish production point of view. It is necessary to identify the harmful species of aquatic plants so that they can be controlled effectively. When considering aquatic plants, the two major categories are algae and vascular plants (macrophytes). Invasive vascular plants, or water weeds are non-native plants that exhibit aggressive growth habits and can outcompete and displace native plant species, contributing to a loss of biological diversity and overall aquatic habitat degradation.

 

Aquatic weeds in fish ponds and their control

 

 Aquatic vegetation can be generally classified as

(i)                 Algae   (ii) Floating (iii) Submerged (iv) Emergent

 

Algae can be unicellular  and filamentous

 

(a)               Unicellular Algae:-Unicellular algae are species of microscopic single celled plants, or colonies of single celled plants, that remain suspended in the water.  They form the basis of life as synthesize oxygen and other complex organic matter. When they become over abundant, they can give the water a soupy green or brown color. This condition is known as an algal bloom. Algae do not bear flower or seeds unlike most other aquatic plants. Their multiplication can be by asexual division, cyst formation or sexual reproductions that result in spore formation.

In pond aquaculture, some of the most problematic algae are single –celled and small multi-cellular species that proliferate in vast numbers eg. Anabaena, Anacystis, Cosmarium, Coelastrum. The dense algal populations are referred as bloom. Though they produce dissolve oxygen they also consume it during night hours causing rapid fluctuation. They also cause wide fluctuation in carbon dioxide, nitrogen and phosphorous levels in pond.Toxic species of algae are Anacystis, Anabaena, Gonyaulax, Gymnodinium and Pfiesteria.

 

(b)      Filamentous Algae:- Filamentous algae are species of plants that consist of visible hair-like strands. These strands may be straight, branched, or even arranged in net-like structures. They may feel slimy, woolly or cottony. These algae begin their growth on the pond bottom, but may float to the surface due to entrapped bubbles produced during photosynthesis. There are no roots and no recognizable plant structures such as stems or leaves. Spirogyra, Lyngbya, Pithophora, Oedogonium is often problematic in pond, cage, pen and race way culture systems. They start growing often at the pond bottom and attach themselves to the hard substrate forming thick mats. They trap the gases in filaments that later on help them to float on the surface. These floating mats of filamentous algae are known as pond scum or pond moss. This kind of algae trap small larval fishes, feed making it unavailable to the cultured fishes. They reduce space and restrict movement of organism, compete for nutrients and restrict netting. The largest multi-cellular or macro-algae species are marine kelps. Some of the algae are promoted in pond as they form the basis of the food chain and therefore have important role in plankton growth.

 

15.2. Floating plants:-  These are aquatic vegetations with roots, free leaf floating on the surface of the water such as water hyacinth (Eicchornia cressipes) Water lettuce (Pistia stratiotes) Bladder wort (Utricularia spp.),Water ferns (Azolla and Salvinia spp.), Duck weeds like Watermeal ( Wolffia columbiana)  are the smallest  flowering angiosperm. Some of the duckweeds are also used as feed for tilapia and grass carp.

                                                                                                                        Marsilia

 

 

15.3. Submerged plants:- It refers to the plants that grow underwater and in some species up to the water surface. They are usually flaccid and depend on the water column for support. Some of these plants may bear flower as well as seed heads extending above the water surface. Hydrilla (Hydrilla verticillata, Egeria (Egaria densa), Eurasian watermilfoil (Myriophyllum spicatum), Pond weed (Potamogeton), Vellisneria,                                           Naiads (Najas)

Coon tail (Ceratophylum demersum ),  Naiads (Najas) are the common examples. They also reduce the effective culture volume of production unit, may entangle larvae, trap feed and restrict light dispersal of            feed and netting

Vellisneria             beside compete with fishes for nutrients and space. The fluctuation in dissolve     oxygen is also other critical parameter affected.

 

 

15.4. Emergent weeds:-These plants are rooted at the bottom and have flexible long stem and long petiole, leaves, flowers etc. the petiole , leaves and flowers are  present on the water surface  example- Typha, Syperus, Eurale.

 

                                                                                                     

                                                                                                                                                                                                                               Typha

15.5. Marginal weeds:- Several rooted plants and grasses occurs in the margina;l region of the water body. These vegetations spread either on the surface of water or on the adjoining land. Example- Ipomea, Penicum, Typha, Marsilia, Cyperus etc.

 

15.6. Duckweed:-Duckweed is the common name for a family of small aquatic herbs known as Lemnaceae that grows in fresh water. They have the unique distinction of being the smallest flowering plants on earth. These plants are also unique in that they do not have any stem or leaf structures. The plant is simply a fleshy ovoid or flattened structure that may or may not bear simple roots. Duckweed is ubiquitous to most temperate and tropical regions of the world, making it readily available to most farmers. They are typically found floating in thick mats of homogeneous populations in quiet streams or ponds containing high levels of organic matter. Another amazing feature of these plants is that they can double their mass in less than two days under ideal conditions of nutrient availability, sunlight and temperature.

 

 

16.2. Harmful effects of aquatic weeds

 

1. The weeds compete for essential nutrients necessary for the production of food of fishes.

2. They also check the penetration of sun light into the water essential for photosynthesis.

3. Dense weed also interfere with fish movement, netting operation and provide shelter to fish enemies (insects, frog, snakes, birds, tortoise etc).

4. Putrefaction of these weeds pollutes the water body.

5. These weeds also convert ponds into swamps by trapping silt and debris.

6. Aquatic weeds require oxygen for respiration at night which causes oxygen deficiency in water, causing difficulties in respiration.

 

Table: 4. Types of aquatic plants

Groups	Scientific name	Common name
Floating	Eichhornia crassipes	Water hyacinth
	Pistia stratiotes	Water lettuce
	Salvinia cucullata	Water fern
	Lemna minor	Duck weed
Emergent	Nymphea Mexicana	Banana water lily
	Nymphea tuberose	Fragrant water lily
	Nymphoides spp.	Floating heart
Submerged	Hydrilla verticillata	Hydrilla
	Najas marina/minor	Najas
	Potamogeton crispus	Curly leaf pondweed
	Vallisneria spiralis	Eel grass
Marginal	Ipomea aquatic	Ipomea
	Jussiaea spp.	Water primrose
	Typha anqustata	Cat-tails
	Cyperus spp.	Cyperus
Algal blooms	Microcystis aeruginosa	Microcystis
	Anabaena	Blue green algae
Algal mats	Pithophora	Horse hair clump
	Spirogyra	Filamentous algae