eChapters

10.1 Emerging Technologies and Innovations in Aquaculture

Aquaculture, the farming of aquatic organisms, is a rapidly growing sector within the global food production system. As the demand for seafood continues to rise, the industry is turning to innovative technologies and practices to ensure sustainable growth, improve productivity, and address environmental challenges. This article explores some of the emerging technologies and innovations that are shaping the future of aquaculture.

1. Recirculating Aquaculture Systems (RAS)

Definition and Concept: Recirculating Aquaculture Systems (RAS) are land based fish farming systems that reuse water by filtering and treating it before returning it to the tanks. This closed-loop system allows for precise control of water quality and environmental conditions.

Innovations and Benefits

• Water Conservation: RAS significantly reduces water usage compared to traditional open-net pen farming, making it suitable for areas with limited water resources.

• Environmental Impact: By treating and reusing water, RAS minimizes the release of pollutants and nutrients into natural water bodies, reducing the risk of environmental contamination.

• Environmental Impact: By treating and reusing water, RAS minimizes the release of pollutants and nutrients into natural water bodies, reducing the risk of environmental contamination.

Human beings came into existence 1 million years ago. Insects which constitute 70-90% of all animals present in this world came into existence 250- 500 million years ago.Insects are highly specialized group of invertebrates belonging to phyla arthropoda characterized by having a bilateral symmetrical body covered by Exoskeleton chitin; with jointed appendages provided with independently movable muscle and inserted in to special pockets of exoskeleton; with a haemocoelic body cavity containing the circulating blood in which are bathed the internal organs; with a dorsal heart and decentralized ventral nerve cord; and with tracheal system for respiration; metamorphosis direct or indirect.

The insects are bilaterally symmetrical tracheate Arthopods is which the body is divided into head, thorax and abdomen. A single pair of antennae is present and head also bears a pair of mandibles, a pair of maxillae,. The thorax possess three pairs of legs and usually two pairs of wings. The abdomen is devoid of any ambulatory appendages and the genital opening is situated near the posterior end of the body. Post embryonic development is rarely direct and metamorphosis usually occurs.

Insect definition

Insects (from Latin insectum, a calque of Greek ?ντομον [éntomon], “cut into sections”) are a class of invertebrates within the arthropod phylum that have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of jointed legs, compound eyes and one pair of antennae.

American Ecologist Whittaker (1969) proposed the five kingdom system of classification. In his ‘Five Kingdom System’, he added three more kingdoms in to Linnean model of two kingdom system. These were: Monera, Protista and Fungi. Whittaker succeeded to overcome the difficulties as well as demerits of two, three and four kingdom systems and to represent the living organisms according to the evolutionary relationships among themselves. He also defined the kingdoms by a number of special characteristics such as whether the organisms possessed a true nucleus or not. Whittaker’s five kingdom system of classification is based on (a) mode of nutrition (b) cell structure and complexity (c) phylogenetic relationship (d) body organization and (e) reproduction.

The large branches within the Animal Kingdom evolutionary tree are ‘phyla’ (the singular being ‘phylum’). ‘Animal phyla’ outlines thirty three phyla, although there are still disputes and disagreements concerning how many phyla are needed to classify the less well-known species. The most easily recognised are Porifera, Cnidaria, Arthropoda, Nematoda, Annelida, Mollusca, Platyhelminthes, Echinodermata, and Chordata. Animal phyla each comprise a branch of the evolutionary tree and these branches are always connected to other branches.

Body Segmentation

In general, insect body is divided in to a series of segments, which in primitive arthropods are known as “somites” or “metameres”. During the process of evolution, these somites gets fused with each other in different ways forming the body parts of the existing arthropods. The type of arrangement of these body segments in embryonic stage is known as primary segmentation while in adult insects is known as the secondary segmentation which differ from primary in having a sclerotized membranous intersegmental region.

In adult and nymphal insects, and hexapods in general, one of the most striking external features is the amalgamation of segments into functional units. This process of tagmosis has given rise to the familiar tagmata (regions) of head, thorax, and abdomen. In this process the 20 original segments have been divided into an embryologically detectable six-segmented head, three-segmented thorax, and 11-segmented abdomen (plus primitively the telson), although varying degrees of fusion mean that the full complement is never visible.

Types of body segmentation.

(a) Primary segmentation, as seen in soft-bodied larvae of some insects. (b) Simple secondary segmentation. (c) More derived secondary segmentation. (d) Longitudinal section of dorsum of the thorax of winged insects, in which the acrotergites of the second and third segments have enlarged to become the postnota. (After Snodgrass 1935)

Endoskeleton of the Head (Tentorium)

• The tentorium forms during development when 2-4 pairs of apophysis/ apodemes (finger-like invaginations of exoskeleton) fuse internally to create a “bridge”.

• The major components of the tentorium are the anterior tentorial arms, the posterior tentorial arms, the dorsal tentorial arms, and the tentorial bridge.

• The anterior tentorial arms originate as invaginations at the lateral limits of the frontoclypeal suture. The coalescence of the anterior tentorial arms forms a more or less solid structure, the tentorial bridge.

• The posterior tentorial arms arise from pits at the ventral ends of the post occipital suture and they unite to form a bridge running across the head from one side to the other.

• In many insects, e.g. Orhtoptera, the central part of the composite tentorium enlarged to form a broad plate referred to as the Corporotentorium.

• The tentorium serves as an internal “truss” that reinforces the head capsule, cradles the brain, provides attachment for muscles and provides a rigid origin for muscles of the mandibles and other mouthparts. The antennal muscles also arise from the tentorium.

Antennae are paired, highly mobile, segmented appendages present between or below or behind the compound eyes. The antennae arise from the 2nd or antennal segment of the head possessing nerves coming from deutocerebrum of the brain. Antennae are absent in order protura and class Arachnida whereas 2 pairs of antenna (antennules) are present in class Crustacea.

Antennae are set in a socket of the cranium called antennal socket (anetnnifer) and connected by an articulatory membrane which allows free movement of antenna. Antennal socket is provided with an antennal suture. Although antennae vary widely in shape and function, all of them can be divided into three basic parts:

• Scape

• Basal segment, larger than other segments and articulates with the head capsule. It is provided with intrinsic muscles.

• Pedicel

• Second segment of antennae. In this, mass of cells called Johnston organ (auditory) is present (eg. houseflies). The above two segments have intrinsic muscles ie., their own muscles. In honey bee, wasps pedicel forms the pivot between scape and flagellum.

• Flagellum/Clavola

• The remaining segments or annuli or flagellomeres are called flagellum which lack individual muscles. Flagellum is supplied with many sensory receptors that are connected by nerves to brain. Flagellum is further divided into three parts

Light spectrum holds rich information about the world. The spectrum of natural illumination changes with daily cycle and objects differ in spectral reflection or emission properties. Like many other animals, insects use chromatic information to f ind favorable habitat, to efficiently locate food sources and to identify conspecific mates using the spectral information. Pollinating insects such as many species of bees and butterflies use their color vision to maximize success in foraging. They detect flowers, memorize the colors and patterns of rewarding flowers, and preferentially collect nectars from the flowers in their later visits. Visual guidance of behaviour is challenging when photons, the elementary particles of light, are scarce. To produce a reliable representation of the surroundings, the visual system must (i) ensure absorption of a sufficient number of photons into a photoreceptor, (ii) house photoreceptors that efficiently convert each photon absorption into a neural signal, and (iii) process these signals appropriately. Insects are a numerous and diverse class of arthropods that have evolved to occupy ecological niches from the brightest to the darkest.

• The thorax is the organ of locomotion due to articulation of wings and legs and is connected with the by neck or cervix.

• Thoracic segments are made up of three sclerites namely, dorsal body plate tergum or nota, ventral body plate sternum and lateral plate pleuron.

• Second and middle tagma which is three segmented, namely prothorax, mesothorax and metathorax. Meso and metathorax which bear wings are called as Pterothorax.

• In the apterygote insects the three thoracic segments are similar in size and structure. In the pterygote insects the thorax is highly modified.

• The prothorax is quite large and is somewhat independent of the other segments. The large shield that covers the dorsal and lateral sides of the prothorax is the pronotum.

• The pronotum is the dorsal sclerite of the prothorax, which can be highly modified in various orders such as the Hemiptera, Blattaria, and Coleoptera. E.g undivided and Saddle shaped in grass hopper, Shield like in cockroach.

• Cockroaches have pronotums that extend forward over the head.

• Scarab beetles and other beetles may also have unusual pronotums.

• Treehoppers have some of the most bizarre pronotums of all insects.

• It is the posterior most and largest region of the insect-body. It is The abdomen is the metabolic and reproductive centre, where digestion, excretion, and the sexual functions take place.

• All the definitive number of segments differentiate in embryo (Epimorphic condition) except protura (Anamorphosis)

• In general more segments are visible in more generalised hemimetabolus insects than in more specialised holometabolus insects. For example in Acridids all 11 segments are visible whereas in muscidae only 2-5 segments are visible

• The basic number of abdominal segments in insect is eleven plus a telson/ tail (Protura) which bears anus. Abdominal segments are called uromeres.

• The undivided tergel plates overlap the sternal ones and the membranous pleura are enclosed in between them.

• The posterior part of each segment overlaps the anterior part of the segment behind it and the two segments are joined by the inter-segmental membrane.

• There are eight pairs of abdominal spiracles. The first pair lies just in front of each tympanum and the other lie dorso-laterally on each of the tergites of the segment to eighth abdominal segments.

• The terga and sterna bear antecostal ridges. The internal dorsal and ventral longitudinal muscles run one antecostal ridge to the other and act as retractors. The contraction of these muscles helps the segments to be retracted. The external muscles originate from the posterior part of the segment and attach to the anterior part of the acrotergite of the next segment. Thus, protraction of these muscles help in the extension of abdomen. Hence, musculature running longitudinally between helps in the contraction and extension of the abdomen.

• The abdominal segments are conveniently divided into three subregions i.e. pregenital, genital and postgenital segments.

Insects development

Once an insect hatches from the egg it is usually able to survive on its own, but it is small, wingless, and sexually immature. Its primary role in life is to eat and grow. If it survives, it will periodically outgrow and replace its exoskeleton (a process known as molting). In many species, there are other physical changes that also occur as the insect gets older (growth of wings and development of external genitalia, for example). Collectively, all changes that involve growth, molting, and maturation are known as morphogenesis.

Metamorphosis

• Metamorphosis actually means change in form Metamorphosis is derived from Greek word ‘Meta’ = Change, ‘morph’ = form or structure.

• The changes in the development from egg to adult, collectively called Metamorphosis (life cycle).

• Post-embryonic changes in form are collectively called as metamorphosis.

• Metamorphosis refers to the way that insects develop, grow, and change form. Metamorphosis include three developmental processes namely growth, differentiation and reproduction which takes place in larval, pupal and adult stages, respectively.

• Majority of insects pass through profound metamorphosis. The growth of an immature insect is accompanied by a series of molts or ecdysis, in which the cuticle is shed off and renewed. The number of molts varies in most insects from 4-8. However some undergo as many as 20 or more molts. A few insects like Bristle tail silver fish (apterygota) may continue molting even after reaching the adult stage. But most of the insects neither molt nor increase in size once then adult stage is reached. The intervals between the ecdysis are called Stadia. The term instar is applied to form of an insect during stadium. In numbering the instar, the form assumed by the insect between hatching from the egg and the first post embryonic molt is termed “First Instar”.

• In most insects, life begins as an independent egg (ovipary).

• Majority of insects are oviparous. Egg stage is inconspicuous, inexpensive and inactive. Yolk contained in the egg supports the embryonic development.

• Eggs are laid under conditions where the food is available for feeding of the future young ones.

• Production of eggs by the female’s body is called oogenesis and the egg laying process is known as oviposition.

• The outer protective shell of the egg is called chorion. Near the anterior end of the egg, there is a small opening called micropyle which allows the sperm entry for fertilization. Chorion may have a variety of textures.

• Size and shape of the insect eggs vary widely.

Alimentary canal of an insect is a tubular structure passing through the body that provides the special internal environment for the food to be mechanically and chemically disintegrated and brought to the vicinity of absorbent cells. Hence, it is involved in the transport of nutrients to the individual cells. It is concerned with ingestion, trituration (chewing), digestion, absorption of nutrient material into haemolymph and egestion of unused food materials. It is tubular structure, which extends from mouth to the anus. It is divided into three distinct regions, namely fore-gut (stomodaeum), mid-gut (mesenteron) and hind-gut (proctodaeum). The fore- and hind-guts are ectodermal in origin and the mid-gut is endodermal.

Longitudinal and circular (intrinsic) muscles are usually associated with each of these three regions and by means peristaltic contractions move the food along the alimentary canal. The functional stomach is the mesenteron usually a circular valve-like fold separates the cavities between stomodaeum and mesenteron is known as stomodael or cardiac valve, and the one closing the entrance to the proctodaeum as the proctodaeum or pyloric valve.

Fore-gut

An insect’s mouth, located centrally at the base of the mouthparts, is a muscular valve (sphincter) that marks the “front” of the foregut. Food in the buccal cavity is sucked through the mouth opening and into the pharynx by contractile action of cibarial muscles. These muscles, located between the head capsule and the anterior wall of the pharynx, create suction by enlarging the volume of the pharynx (like opening a bellows). This “suction pump” mechanism is called the cibarial pump. It is especially well-developed in insects with piercing/sucking mouthparts.

The sense organs in an insect body are distributed on different parts and respond to a given stimulus such as light, sound, touch, chemicals etc. The sense organs may be classified as • Visual organs (or) photoreceptors • Auditory organs (or) organs of hearing

• Chemoreceptors which respond to chemicals

• Tacticle receptors which respond to touch

• Gustatory receptors which respond to taste.

Photoreceptors

Light is perceived by insects through a number of different sense organs and these are the organs that react with light and useful for vision. These are of different types, but most important are the compound eyes.

Compound eyes

History

• Aristotle (384-322 BC): A good beginning of taxonomy was made by Aristotle (Historia Animalium). He erected entomon. He could distinguish mandibulates and haustellates; winged and wingless forms. The insect orders like coleopteran, dipteral, psyche (Lepidoptera) were created by him. Hence, he was called as Father of Biological Classification.

• Linnaeus (1707-1778): Father of Taxonomy and Binomial Nomenclature. He coined the term Insecta. He used the term Systematics. His greatest contribution is Systema Naturae.

• Brawer (1885): Laid foundations for modern system of classification and responsible to divide class Insecta into Apterygota and Pterygota.

• Michael Anderson (1727-1806): Contemporary and rival of Linnaeus. Introduced Numerical Taxonomy and hence is called Father of Numerical Taxonomy. 

• Johan Christian Fabricius (1745–1808), the first systematist considered to specialize on insects, published in 1778 his Philosophia Entomologica (40), the first textbook of entomology.

• Fabricius had already set forth his system of insects in 1775 (Systema Entomologiae), his system of genera in 1776 (Genera Insectorum), and then numerous works on species, culminating in individual accounts of the species of each order

Apterygotes

The Apterygota, which formerly included the other primitively wingless insects currently placed in the class Entognatha, are now restricted to the two orders Archaeognatha and Zygentoma, which in turn were formerly united as the Thysanura. Despite the superficial similarity of the two groups, it is now clear that they are not closely related, mainly because of fundamental differences in the mouthparts. The Archaeognathous mandibles are monocondylic, having a single articulating point with the head so that the mandible can rotate. The Zygentomous mandibles are dicondylic, with two articulating points that restrict the motion to a single plane yet enable the development of a much stronger biting action; this is the type found in all the higher insects, and the Zygentoma may well be the sister group of the Pterygota, or winged insects. Clearly the ‘Apterygota’ is not a monophyletic group and is simply retained for convenience in grouping these two orders that superficially resemble each other and have similar life histories.

• The name Zoraptera, derived from the Greek “zor” meaning pure and “aptera” meaning wingless was given to the order before winged forms were discopvered.

• Members of the order Zoraptera are small (less than 4 mm) and usually found in rotting wood, under bark or in piles of old sawdust.

• They live in small aggregations (gregarious) and appear to scavenge on spores and mycelium of fungi, or occasionally, on mites and other small arthropods.

• polymorphism in populations; with blind, apterous individuals dominating during colony life, but populations produce eyed alates (individuals with wings) for dispersal and founding new colonies.

• males with a distinctive “mating hook” and unique mating behaviors.

• unique grooming behaviors

Adults

• Antennae 9-segmented (moniliform).

• Mouthparts mandibulate, hypognathous.

• Soft bodied, small (usually less than 3 mm).

• Wings often absent with reduced venation when present.

• Tarsi 2-segmented

• Cerci 1-segmented

• ovipositor absent

• incomplete development (egg, nymph, adult)

The name Lepidoptera derived from the Greek words “lepido” meaning Scale and “ptera” meaning wings refers to the flattened hairs (Scales) that cover the body and wings of most adults. Lepidoptera (Moths and Butterflies) is the second largest order (1.10 lakh sp.) in the class insecta, characterized by the body, wings and appendages being generally covered densely with pigmented scales which provide the colour pattern of the characteristic of the species and play an important role in courtship and intraspecific recognition.

Adults

• Head: Hypognathus and relatively small.

• Compound eyes are large and set well apart. Ocelli two in number in moths or reduced to Chaetosoma in butterfly.

• Mouthparts form a coiled tube (Proboscis) beneath the head.

• Antennal type:

• Butterflies: Clubbed, clavate, capitate.

• Moths: Pectinate (Uni/Bi).

• Adults have siphoning type mouthparts except in micropterygidae (Mandibulate mouthparts). Front wings large, triangular, hindwings large, fan shaped.

• Body and wings covered with small, overlapping scale.

• Thoracic segments are fused and metathorax is the largest and most prominent.

• Wings covered with scales. Androconia (Plumules) on upper surface of wings in some males serves as outlet for odouriferous glands. are fringed distally with each tip finely divided. • Wing coupling apparatus variable (generally Frenulum and retinaculum or Amplexiform type)

Introduction

Fruit crops have been cultivated for centuries, both commercially and in amateur gardens, and many species covering a wide range of trees, shrubs, and non-woody perennials.Fruit crop species have certain common characteristics: they are long-lived, usually highly heterozygous, and clonally propagated from an elite mother plant. Fruits are increasingly recognized as an important component of a healthy diet, and consumption of temperate fruit and fruit products, especially juices and dairy derivatives, has risen sharply over the past decade.China is the largest producer of fruit crops with approximately.

• India ranks the second in fruit production.

• India has witnessed increase in horticulture production over the last few years. Significant progress has been made in area expansion resulting in higher production.

• Over the last decade, the area under horticulture grew by 2.6% per annum and annual production increased by 4.8%.

• Production of fruit crops has increased from 50.9 Million Tonnes to 97.35 Million Tonnes since 2004-05 to 2017-18.

• Total production of fruits is highest in case of Andhra Pradesh followed by Maharashtra.

Introduction

• The green revolution of the 1960s and 1970s ended chronic food deficits and while cereals still command the attention of policy makers, fruit production has surged impressively, making India the second largest global producer behind China.

• Annual growth in horticulture has seen fruit production grow at faster rate and constitute the larger segment of agriculture. • No doubt, there has been manifold increase in area, production and productivity but when we compare the productivity of various major fruit crops with other developed countries, our productivity is very low.

• This may be mainly attributed by non-availability of quality planting material and seeds, existence of old unproductive seedling orchards, small and unirrigated land holdings, use of inferior genetic stocks/ varieties/hybrids, poor management and non-adoption of package of practices, high incidence of pest and diseases, heavy pre and post harvest losses and lack of trained human resource.

• To meet increasing demand the productivity per unit area per unit time and per unit investment has to be increased from limited land resources, where production and supply of quality planting material of elite varieties is one such important factor that can bring tremendous improvement in production, productivity and higher economic returns to farmers.

• This may be mainly attributed by non-availability of quality planting material and seeds, existence of old unproductive seedling orchards, small and unirrigated land holdings, use of inferior genetic stocks/ varieties/hybrids, poor management and non-adoption of package of practices, high incidence of pest and diseases, heavy pre and post harvest losses and lack of trained human resource.

Introduction

• At present, horticulture is recognized as a potential sector to enhance agricultural production, improve house hold nutritional security and income generation through diversification and employment, value addition and export.

• Inspite of the enormous success achieved in horticulture sector, several constraints still exist.

• Besides new emerging challenges, poor productivity per unit area continues to be a concern in most of the horticultural crops with climate change impacting the productivity further.

3.1 Role of root stock in fruit crops

• The role of rootstocks and its use in different fruit crops has significant impact on fruit crop production by influencing canopy architecture, nutritional uptake, flowering, yield and fruit quality.

• Besides, it can also confront biotic and abiotic stresses such as soil pathogens, thermal stress, salinity and nutritional stress.

• Due to limited availability of arable land and high market demand for fruit crops, they are frequently cultivated under unfavorable soil and environmental conditions like thermal stress, drought, flooding, salinity and contamination of organic pollutants.

• One way to substantiate or reduce these losses in production would be the use of appropriate rootstocks, which are capable of reducing the effect of external stresses on the scion.

• Rootstocks have a primary role in determining orchard efficiency.

• They are responsible for water and mineral uptake and provide anchorage for the tree.

4.1.1 Vertical row planting pattern

1. Square system: In this system, trees are planted on each comer of a square whatever may be the planting distance. This is the most commonly followed system and is very easy to layout. The central place between four trees may be advantageously used to raise short lived filler trees. This system permits inter cropping and cultivation in two directions.

2. Rectangular system: In this system, trees are planted on each corner of a rectangle. As the distance between any two rows is more than the distance between any two trees in a row, there is no equal distribution of space per tree. The wider alley spaces available between rows of trees permit easy intercultural operations and even the use of mechanical operations.

4.1.2 Alternate row planting pattern

3. Hexagonal system

• In this method, the trees are planted in each comer of an equilateral triangle.

• This way six trees form a hexagon with the seventh tree in the centre.

• Therefore, this system is also called as 'septule' as a seventh tree is accommodated in the centre of hexagon.

• This system provides equal spacing but it is difficult to layout.

• The perpendicular distance between any two adjacent rows is equal to the product of 0.866 x the distance between any two trees.

• This system accommodates 15% more trees than the square system. The limitations of this system are that it is difficult to layout and the cultivation is not so easily done as in the square system.

5.1 Crop modelling

• Crop model

• “Schematic representation of the system’’i.e. a model as defined by De Wit 1970.

• Such a model can be based on statistics applied to a set of experimental data or on physical laws (Guyot, 1997).e.g. Irrigation is able to satisfy a crop’s water needs provided its management relies on the measurement or estimation of evapotranspiration. The manager can either invest in equipment to monitor changes in water content in the soil or fluxes of water into the plant or the atmosphere, or rely on a ‘‘schematic representation of the system’’, i.e. a model.

• In very simple terms we can define a crop model as “a well-thought out plan of activities to grow the desired crop to get maximum possible yields of high-quality produce with the given resources. It can be a mental or a written exercise (a “schematic representation of the system”) that a farmer or a farm manager prepares for a crop or for an individual crop”.

• In other words, we can also say that a model is “an attempt to describe a certain process or system through the use of a simplified representation, preferably a quantitative mathematical expression, that focuses on a relatively a few key variables that control the process or system”.

• It is clear that in finalizing a crop model we have to assume some mean or standard values (based on the past record, experience, expert judgment, etc.) of the variables which we may not be taking explicitly in our model.

6.1 Scenario in precision farming

• India’s population is around 1366 million by 2020 which requires food grain production of 350 million tones.

• Considering the current food grain production levels, India needs to raise food grain production levels by not less than 4.00 per cent per year. As the availability of land has decreased, application of fertilizers and pesticides become necessary to increase food production.Indiscriminate use of inputs coupled with improper management practices over a long period has resulted in decline in soil productivity.

• Agriculture production system is outcome of interaction of various agro inputs. Therefore, judicious management of these inputs is necessary for the sustainability of these inputs.

• In our agriculture systems, spatial variability over the landscape is ignored and fertilizers, herbicide, pesticides, fungicides etc. are applied at uniform rate over the whole field.

• It has been recognized that crops and soils are not uniform within a given field. The management of in-field variability in soil fertility and crop conditions for improving crop production and minimizing the environmental impact is the crux of precision farming.

• Definitions • It is defined as the application of technologies and principles to manage spatial and temporal variability associated with all aspects of agricultural production (Pierce and Nowak, 1999).

• It is an integrated information and production-based farming system that is designed to increase long term, site specific and whole farm production efficiency, productivity and profitability while minimizing unintended impacts on environment.

Introduction

• India is the second largest producer of fruits in the world after China

• India is rich in fruit diversity starting from tropical, subtropical to temperate region.

• Some of the fruits like Guava, pomegranate, lemon, mandarin etc., if left without any treatment, give several light harvests of the variable quantities and qualities from the various flowering flushes throughout the year.

• Some of the fruit crops bloom throughout the year without any resting period and produces two or three crops (bahar) in a year but yield and quality is not so good in all crop harvest. So, it is very essential to understand the flowering and fruiting behavior of crops and which bahar will give good crop with considering all the factors associated with a particular bahar.

7.1 What is crop regulation?

• Crop regulation means to force the tree for its rest and to produce blossom and fruits during any one of two or three flushes”

• Crops in which flowering is continuous throughout the year; economic yield cannot be achieved in any of the season.

• Therefore, by analyzing market demand flowering can be forced in particular one season, which gives the economic yield.

• Through various techniques like cultural practices and chemical treatments, trees are thrown to rest prior to flowering and then practices are done to trigger flowering.

• Thus, crop regulation is a method to regulate flowering by altering natural tendency of the tree by artificial means.

8.1 What is stress?

• Physics:Mechanical force per unit area applied to an object.

• Biology:Stress is any adverse environmental factor or condition that affects normal metabolic or physiological processes. It may be :

• Biotic stress (living) • Abiotic stress (non-living) 8.2 Abiotic stress

• Abiotic stress is defined as:“The negative impact of non-living factors on the living organisms in a specific environment”

• Only 10% of the world arable land may be categorized as free from stress.

8.2.1 Type of abiotic stress

8.2.1.1 Temperature stress

• Temperature is one of the most important components of climate. It plays vital role in the production of horticultural crops.

• The different activities of plant like growth and development, respiration, photosynthesis, transpiration, uptake of nutrients and water and reproduction (Such as pollen viability, blossom fertilization fruit set etc.), carbohydrate and growth regulators balance, rate of maturation and senescence, and quality, yield and shelf life of the edible products.

• The above function of the plant should be well when the temperature at the optimum range.During high temperature plant does not perform proper functions of growth, where in low temperature physiological activities of the plant are stopped.

Introduction

• Successful horticultural production is not possible without sufficient moisture regimes and for that, the appropriate techniques should be adopted.

• In the total cultivated land of India, 75 % of land contributed as a rainfed area or dry land area in which 60% with semi-arid and 19.3 % of area with arid zone.

• The irrigation facilities are covered only 38 % of the total cultivated land of the country.

• The moisture is always the limiting factor in arid area.

• So, conservation of soil moisture or water management is the most important task for arid fruit production.

• Out of total cultivated area of Horticultural production, l lakh ha is under arid or semi-arid.

• In arid area, some fruit crops with specials features are adapted for their production. So, in this area, the soil moisture conservation or the water harvesting techniques is the prime important tools for crop production with best management systems.

10.1 What is nutrient management?

• Nutrient management is an important component in orchard management for high efficiency and high fruit quality. Fruit trees are perennial woody plants which can store nutrients and then release them for growth.

• Therefore, the nutrient uptake of fruit trees includes the total nutrients of the fruits, leaves, new branches, and time increments of storage. Nutrient uptake is different under different yield levels. For example, the N uptake of apple trees was 100–120, 110– 130,120–140, and 130 150kg/ha under yield levels of 30, 45, 60, and 75t/ha, respectively.

• Basal fertilization is considered to be important for high-quality fruit production by providing nutrients for tree growth and also improving soil structure which promotes better root development. It is usually recommended and immediately applied during the dormant season up to autumn, after fruit harvest.

• Top dressing applications are usually chemical fertilizers which are applied two to four times before bud break or prior to or after blooming and at the fruit enlargement stage, depending on the requirements of each type of fruit tree.

• Using this INM method, the total nutrient demand is calculated according to target fruit yield level and NPK fertilizers are recommended based on soil fertility index (High, Moderate, and Low soil fertility) and nutrient demand with different stages. For moderate apply trees, most of N fertilizer is applied in autumn after picking to add N storage and renew tree vigor, and most of the P fertilizer is applied in spring with flowing stage to improve flower bud quality, and most of the K fertilizer is applied in summer fruiting period to improve fruit quality. Management of high yielding fruits using suitable pruning, and irrigation, are combined in this INM

11.1 Quality

• Quality of fruit or any other commodity is combination of attributes, properties or characteristics like appearance, texture, flavor and nutritive value that determine their value to the consumer.

• Keeping quality is also an important quality attributes in all fruits.

• Quality parameters • Appearance (size, shape, color and freedom from defects)

• Texture (firmness and juiciness)

• Flavors (swetness, sourness, bitterness, astringency, aroma and off f lavour)

• Nutritional (vitamins and minerals)

• Quality management Quality management is a method of ensuring the effectiveness of all the factors those implemented to improve and maintain the quality in acceptance form at consumer’s level.

11.2 Pre-harvest management of quality

11.2.1 Genotype and rootstock management

INTRODUCTION

Ecosystem services and biodiversity conservation are well recognized as essential to human well-being and have become a policy priority. India is gifted with a large coastline and vast stretches of coastal wetlands. The estuaries and back waters which may include mangroves, mud flats, bays etc. extend over a large part of the Indian coasts. The mangrove ecosystem functions as a habitat for nurseries, thus benefiting fishers in the food chain (Mumby et al., 2004; Venkatachalam et al., 2018). Mangrove habitats increase the survival ratio of young fish that migrate to other offshore habitats when they mature, resulting in the enrichment of fish biomass in adjacent mangrove areas (Mumby et al., 2004; Aburto-Oropeza et al., 2008). Mangroves enhance fish production by providing food and shelter to fishery resources. Mangrove forests are highly productive, with average primary productivity level similar to that of tropical terrestrial forests (Alongi, 2009). Therefore, mangrove loss could have a devastating effect on fishery outcomes. The estimated fish catch is up to 70% higher in mangrove areas than in non-mangrove areas (Das, 2017).

NATURE OF MANGROVE FORESTS

Mangroves are amongst the most productive marine ecosystems on the Earth, providing a unique habitat opportunity for many species and key goods and significant services for human beings. They are salt tolerant plants, and are found distributed growing in estuaries, lagoons, backwaters and bays at the land-sea interface in tropical and subtropical areas of the world. Mangroves thrive on low-oxygen through the breathing roots or pneumatophores that are used for respiration. They need freshwater for their growth and so they live at the sea edge, they must remove the salts from the water that is taken in by the roots.

INTRODUCTION

Biodiversity can be useful as an ecosystem indicator for conservation and monitoring, through continuous assessment of its main properties including stability, primary productivity, exploitation tolerance and even global environmental changes (Douglas et al., 2012). Crustaceans are found one of the most morphologically diverse taxonomic groups on the planet (Martin and Davis, 2001). Among them, decapods are the most studied taxon, mainly on account of the commercial interest of some species and their great diversity (Isarch and Munoz, 2015). Decapods are chiefly composed of marine species that live in waters depths ranging from shallow to deeper than 5000 m. Isarch and Munoz (2015) described the importance of this group lies in several factors such as the great biomass they represent, their significant role in marine food webs and the commercial interest of many decapod species. Order Decapoda comprises the commercially important shrimps, crabs and lobsters. Out of 649 species of marine crabs so far recorded from Indian waters, only 12 species of edible crabs namely Portunus sanguinolentus, P. plagicus, Charybdis feriatus, C. lucifera, C. annulata, C. natator, Scylla serrata, S. tranquebarica, Matuta lunaris, Sesarma tetragonum and Varuna litterata, which inhabit the coastal waters and adjoining brackishwater environments, support commercial fisheries (Menon and Pillai, 1996). However substantial quantities of crabs are landed every year as by-catches of shrimp trawlers and indigenous fishing units throughout the county.

India represents one of the major contributors to the world production of marine crustaceans. Shrimps constitute as the main seafood export industry for the major foreign exchange earner as well as a source of livelihood for millions of fish workers. As shrimps are targeted for fishing, information on the present status of the fishery is critical for implementation of proper management. Some of the important penaeid shrimps that support commercial fisheries along the Indian seas are Fenneropenaeus indicus, P.semisulcatus P.monodon, P.merguiensis, P.japonicus, P.penicillatus, Metapenaeus dobsoni, M.monoceros, M. affinis, M. kutchensis , M. brevicornis, Parapenaeopsis stylifera, P.hardwickii, P.sculptilis, P.maxillipedo, P.uncta, Trachypenaeus curvirostris, Metapenaeopsis stridulans, Parapenaeus longipes, Solenocera crassicornis and S.choprai (Mohan Joseph and Jayaprakash, 2003). Rajkumar et al. (2015) carried out molecular identification of shrimp species, Penaeus semisulcatus, Metapenaeus dobsoni, Metapenaeus brevicornis, Fenneropenaeus indicus, Parapenaeopsis stylifera and Solenocera crassicornis from Tamil Nadu, India.

INTRODUCTION

Species of the Clupeiformes (Teleostei), commonly known as herrings, shads, menhadens, sardines, anchovies, and their relatives, are a major component of forage fishes in coastal ecosystems and dominate worldwide forage fish landings (Tacon and Metian, 2009a; FAO, 2020). Clupeiformes are globally distributed fishes with having nearly 419 marine, freshwater, and diadromous species (Bloom and Egan, 2018) and they are filter-feeding fishes that form large schools having a diverse group of trophic guilds and habitats (Bloom and Egan, 2018). Additional to providing ecological and economic support, clupeiforms contribute to global food security given their abundance, easy access, and exceptionally high nutrient content (FAO, 2018). In some human communities, clupeiforms comprise the major or the sole protein source (Alder et al., 2008; Mohanty et al., 2019). Historically, clupeiform presence has been associated with persistent human settlement, growth, and survival (Thornton et al., 2010; Levin et al., 2016).

Clupeiform fishes are ecologically diverse and span all aquatic habitats, including coastal and open marine environments, oceanic islands, estuaries, and freshwater rivers and lakes (Whitehead, 1985; Lavoue et al., 2013). Species can be restricted to marine, estuarine, or fresh waters, or they can be euryhaline, where a subset exhibit diadromy (Whitehead, 1985). Strictly marine clupeiforms (33.7% of all species) are distributed in every ocean, except for the Southern Ocean (Whitehead, 1985), while strictly freshwater species (17.8% of all species) are found on every continent except for Antarctica (Bloom and Egan, 2018). Major threats to clupeiforms are similar to those found for other groups of fishes (e.g., Roberts and Hawkins, 1999; Reynolds et al., 2005), with overexploitation as the leading threat for all clupeiforms in all habitats. While overexploitation may be the most prolific threat by impacting the highest number of clupeiforms, pollution may be the most detrimental, as it affects greater numbers of CR species. When compared to other economically and ecologically important fish groups globally assessed using the IUCN Red List methodology, clupeiforms have the lowest estimated percentage of threatened and NT species overall. Using the midpoint of species evaluated as elevated concern, roughly 11% are currently at high risk compared to approximately 22% of tunas and billfishes (Collette et al., 2011), 19% of sparids (Comeros Raynal et al., 2016), and 19% of groupers (Sadovy de Mitcheson et al., 2020).

INTRODUCTION

Coral reefs are fragile and most diverse and valuable ecosystems on earth. The stony corals are formed from the tiny, soft colonial organisms called polyps. They provide enormous ecological, economic services, and cultural value to hundreds of millions of people. They are significantly contributing to the nutrition, economic security and protection from natural disasters. They are often termed as the rain forests of the sea.

Coral reefs were first appeared 485 million years ago during the early Ordovician period. They belong to the class Anthozoa of animal phylum Cnidaria, which includes sea anemones and jelly fish. Coral reef is an under water ecosystem which is characterized by reef-building corals. Unlike sea anemones, colonies of coral polyps secrete a hard exoskeletons called reef which is made up of calcium carbonate to support and protect the corals. These reefs grow best in warm, shallow, clear, sunny and agitated water.

BIODIVERSITY

The term biodiversity was coined by Walter G. Rosen in the year 1985. Biodiversity refers to the variation among living organisms that can be found in a particular area such as terrestrial, marine and desert ecosystems and the ecological complexes to which they are a part. The study of biodiversity helps to understand the ecological stability, economic and ethical importance. Coral reefs are believed to have the highest biodiversity on the planet even more than a tropical rainforest. Though the coral reefs distributed in less than one percent of the ocean floor, they provide habitat for more than 25% marine life with more than 4,000 world’s fishes. They act as protective nurseries to many fish species, and shelter small fishes to grow. Coral reefs diversity is so rich that we do not have a firm count on all the species that live within it and every year discover new species.” There are about six thousand coral species in the world, in which few are growing in warm shallow waters near coastlines while others in the dark, cold seafloor of the open ocean.

Increasing pressures exerted on the environment by humans make protection of natural areas crucial for the preservation of biological diversity. Protected areas are one of the most effective tools available for conservation of biodiversity.

The IUCN defines a Protected Area as ‘an area of land and/or sea specially dedicated to the protection and maintenance of biological diversity, and of natural and associated cultured resources, and managed through legal or other effective means.

Since 1986, the IUCN commission on National Parks and Protected Areas (CNPPA) has been promoting the establishment and management of a global representative system of Marine Protected Areas (MPAs) which play a critical role in the conservation of biodiversity. MPAs are growing in importance globally as practical and potentially effective options for the management of fisheries, the protection of biodiversity and the generation of income from eco-tourism. The effective management of MPAs to ensure that they meet their declared objectives poses many challenges.

The IUCN has defined an Marine Protected Area (MPA) as ‘Any area of the intertidal or subtidal terrain, together with its overlying water and associated flora, fauna, historical and cultural features, which has been reserved by law or other effective means to protect part or all the enclosed environment (Kelleher,1999).

Study done in India on various aspects of marine copepods are those of Krishnaswamy (1952), Kartha (1959), Ummerkutty (1960, 1966), Ganapathi et al. (1961), Kasturirangan (1963), Saraswathy (1966), Abraham (1970), Silas and Pillai (1973), Sarladevi (1979), Sarkar et al. (1985), Madhupratap and Haridas (1986), Wells and Rao (1987), Gajbhiye et al. (1991), Madhupratap (1999), Kesarkar and Anil (2010), Ramanibai and Shanthi (2011), Srichandan et al. (2014). Jayabarathi et al. (2015), Nishida et al. (2015), Arunpandi et al. (2017), Loka et al. (2017), Deepika et al. (2019), Kaviyarasan et al. (2019), Khandagale et al. (2022), Nawaz et al. (2023), Thangaraj and Vijayanand (2023).

Copepods are planktonic crustaceans, which occur in marine, fresh as well as brackish waters. They represent about 80% of the zooplankton in the ocean. There are more than 210 families, 2400 genera and 24000 species identified in this group. Planktonic copepods are considered to be the most abundant metazoans on earth.

The name 'copepod' is derived from the Greek words meaning 'animals with oar shaped foot' i.e., ‘kope’ means oar and ‘podos’ means foot (Stottrup,2003). Copepods are important secondary producers and primary consumers and ultimately contribute significantly to the food chain in large ecosystems.

Copepods are very hardly planktonic forms which can withstand most of the unfavourable conditions and can produce diapause eggs and resting eggs to survive in these conditions. Most of the copepods can adjust wide range of salinity and temperature levels. Due to its hardy nature, copepods can be easily introduced into all types of water bodies.

Copepods forms important food for many aquatic animals especially fishes. Certain fishes and fish larvae were evolutionary adapted to feed on copepods. Copepods have been found to be nutritionally superior to almost all other live feeds.

INTRODUCTION

The Food and Agriculture Organization (FAO) of the United Nations defines aquaculture as the cultivation of aquatic organisms such as fish, mollusks, crustaceans, and aquatic plants by individuals or corporations. In aquaculture, interventions are made in the rearing process to enhance production. While aquaculture is a practice with origins dating back more than 3000 years, Aquaculture products have only recently been recognized by the United Nations Statistical Commission as distinct global commodities, despite the practice having origins dating back more than 3000 years. According to the FAO's "Global Aquaculture Production" database, the annual global production of aquaculture has increased at an average rate of around 8% over the past three decades (since 1980). Despite a recent slowing in global trends, growth remains higher than any other major animal food production sector. This rapid global increase in production is occurring alongside a slow decline in marine fisheries catches. There is a growing global focus, largely driven by demand from Western countries, on increasing the intensive production of omnivorous and carnivorous species farmed and harvested in maritime and brackish coastal environments, a practice known as mariculture. The farming of these species, such as salmon, groupers, seabasses, and prawns, typically relies heavily on inputs such as wild post-larvae and juveniles, fishmeal, fish oils, as well as significant amounts of water, land, and energy. As a result, mariculture has faced widespread criticism due to its often negative impacts on marine and coastal ecosystem health. Negative associations have been drawn between mariculture and its effects on marine capture fisheries and food security.

INTRODUCTION

The aquaculture industry is regarded as one of the most advanced food production industries globally. From 2010 to 2020, it grew at an average annual rate of 4.6%, reaching 122.6 million tonnes of live weight (FAO, 2022). Sustainable aquaculture proposes numerous profits to attain economic progress through well usage of natural resources (FAO 2017). The expansions in the sustainable aquaculture business are challenging due to the inadequate number of available natural resources and industrialized effects that released to the surround environments (Costa-Pierce et al. 2012; Verdegem 2013). Particularly in intensive system, increased higher organic matter concentrations raise several future issues, including acute harmful, chronic impacts (Piedrahita 2003). Recently, Innovative biofloc technology system (BFT) is one of the most popular methods to combat these problems.

Biofloc is a climate-smart technology that relies on mass synthesis of in situ microorganisms (Ogello et al., 2021). The BFT permits high stocking densities and higher fish productivity (Ogello et al., 2021) while requiring limited or zero water exchange in to sustain the flocs (Emerenciano et al., 2017). The power of BFT aligns with the "cradle to cradle" concept that outlined by McDonough and Braungart (2002), which omits the phrase "waste”. In BFT, nitrogen wastes that generated from feces of aquatic animals and residual feeds are transformed into the microbial protein that becomes feed for the same creatures (Minaz and Kubilay 2021). Numerous microorganisms, including bacteria, microalgae, protozoa, and zooplankton, are present in biofloc particles (Ray et al. 2010a). Hence, biofloc can incorporate the diet of aquatic species, which utilises the natural productivity in the culture system as a feed source (Wasielesky et al. 2006; Emerenciano et al. 2012a). This microorganisms are recognised for their contributions to (i) preserving high water quality (Emerenciano et al., 2017), (ii) enhancing culture efficiency by lowering feed conversion ratio (FCR) and costs of feed (Hargreaves, 2006). (iii) biosecurity (Defoirdt et al., 2004), and (iv) conserving greenhouse gases (GHG) (Manan et al., 2016). These four biological roles of microorganisms in BFT units are factors of high fish production, profitability and environmental protection (Ogello et al., 2021).

INTRODUCTION

Aquaculture is a technology driven industry which relies a lot on research to develop species diversification in culture system as well as in the appropriate technology for commercial production. The rapid development of aquaculture in the world depends largely on the availability of fish feed; which are traditionally based on fish meal as the main protein source (Hardy & Tacon, 2002; Krishnankutty, 2005; Yigit et al., 2006) but the major challenge is its availability, quality and cost (Ghazala et al., 2011; Tabinda and Butt, 2012). In the aqua feed formulation, protein is the main but expensive ingredient and its quality and quantity in fish feeds formulation plays a vital role in promoting fish growth (Pandian, 2001). Dietary protein provides essential and non essential amino acids to synthesize body protein and energy for maintenance. According to fish species, fish size, dietary protein sources and environmental conditions protein requirements ranges from 300 to 550 g /kg (NRC 1993).

In India there is a significant development in fresh water aquaculture in last few decades contributing greatly to overall fish production of the country. The fresh water aquaculture is crossing the traditional boundary of concentration on farming of major carp and entered the arena of diversification to the culture of other species like catfishes. So far in India majority of research works were concentrated on development of commercial fish feed mainly for carps and shrimps. To fulfill the objectives of large scale culture of cat fishes and development as an economic proposition, it is necessary to take up induced breeding and larval rearing of commercially important catfishes in controlled conditions and develop easily adoptable package of practices of the same to cater to the needs of interested fish entrepreneurs. Among the catfishes, Clarias magur, an air breathing species and popularly known as ‘magur’ or ‘walking catfish’ is a high valued fish in the Indian subcontinent and fetches higher price than many other fishes including major carps and it is highly revered for its nutritious flesh which is therapeutic in nature, hence, better prospects are there for developing its culture (Hussain et al., 2016). Vishwanath (2010) reported that this species is very much popular in Bangladesh due to use as important part of the diet for children and lactating mothers and also prescribed as diet for the convalescent of the patients. This fish is highly regarded for food due to its high protein (15.0%), low fat (1.0%) and high iron content (710mg/100g tissue). Paul et al. (2015) in their studies on Indian catfish namely magur (Clarias batrachus) and singhi (Heteropneustes fossilis) for proximate composition and mineral content concluded that both the fishes are rich in protein, fat and minerals content irrespective of their size and season.

INTRODUCTION

An expanding aquaculture industry that offers high incomes and job opportunities to people worldwide is ornamental fish farming. With over 2 billion live ornamental fish traded globally, the ornamental fish trade has become a very lucrative sector (Das & Biswas, 2016; Katia, 2001) with global net worth of more than 20 billion USD. According to Saxena (1994), the most significant factor influencing an ornamental fish's market value is its vibrant body colouration. Fish are incapable to synthesize carotenoids De novo (Goodwin 1951),and rely on dietary carotenoids for its body pigmentation (Hata and Hata, 1973). So, there is hence a direct correlation between pigmentation and dietary carotenoids(Halten et al., 1995). Aquatic animals' skin, meat, shell, and exoskeleton are coloured red, orange, and yellow due to a class of naturally occurring lipid-soluble organic pigments called carotenoids (Pailanet al., 2012). Fish skin and muscle colour regulation is significantly influenced by dietary carotenoids (Ahilan et al., 2008). The freshwater ornamental fish industry has encountered the issue of fadingfish body colouration, particularly in cases where the fish are reared in captivity for extended periods of time and subjected to rigorous cultivation conditions (Das and Biswas, 2016). According to Das and Biswas (2016), an ornamental fish's food should generally be nutritionally balanced, appetizing, resistant to crumbling, water stable, buoyant, and enhance or retain the fish coloration.

The phenomena of coloration in fish are quite significant and have a direct impact on its aesthetic value. If pigment-enriched feed can be prepared and used to increase coloration, the fish will undoubtedly have better quality and a cheaper price tag. Detailed research on colour enrichment in native ornamental fish using formulated feed is lacking (Das and Biswas, 2016). For the purpose of colour enrichment in fish, native plant sources have been used. Choubert (1979), Boonyaratpalin and Phromkunthong (1986), and Alagappan et al. (2004), utilized spirulina as a source of carotenoid colours for fancy carp and rainbow trout. Enhancement of pigmentation of Cyprinus carpio and Carassius auratus with microalgal biomass supplementation has demonstrated that Chlorella vulgaris is just as effective as synthetic colours (Gouveia et al., 2003). Alagappan et al. (2004) observed increased body pigmentation in Trichogaster trichopterus using Spirulina sp. algae as a source of carotenoid pigment. The body pigmentation of goldfish (Carassius auratus L.), red swordtail (Xiphophorus helleri), and tiger barb (Puntius tetrazona) was enhanced by feeding with marigold petal diet (Boonyarapatin and Lovell, 1977; Ezhil et al., 2008; Alma et al., 2013). Using natural sources of carotenoid pigments to improve the colour of ornamental fish is a cost-effective and ecofriendly solution. Due to the aforementioned information, the current study was carried out to assess how dietary natural carotenoids from source such broccoli (Brassica oleracea var. italica) effects the development and coloration of Blue Gourami, Trichogaster trichopterus, one of the important ornamental fishes with high market value.

INTRODUCTION

Fish live in a variety of watery habitats and comprise around 50% of all vertebrate species worldwide. There are approximately 21,723 known living fish species out of a total of 39,900 vertebrate species, with 8,411 found in freshwater habitats and 11,650 in marine environments (Jayaram, 1999). Fish are used as markers of contamination and contribute significantly to the preservation of human history and welfare, either directly or indirectly. According to Mittermeier et al. (1997), India ranks eighth in the world for freshwater biodiversity, making it one of the nations with significant biodiversity. There are over 2,500 fish species in India; roughly 930 of them are found in freshwater environments, and roughly 1570 are found in marine ones (Kar et al., 2006).

Fish diversity is particularly rich in the northeastern part of the nation; studies have shown that there are 267 freshwater fish species from 114 genera distributed over 38 families and 10 orders (Mahanta et al., 2003). Fish plays a crucial role in Assam's cuisine, where a wide range of fish species may be found in the region's floodplain wetlands because of the subtropical climate, favorable ecological and topographical circumstances, and inherent capacity for stocking. Assam's waters, including its wetlands, are home to around 217 fish species, representing 104 genera, 37 families, and 10 orders, according to Goswami & Singha (2023). Assam's lakes and marshes are vital for supplying the state's domestic fish needs, fostering economic growth, and giving the general public access to fairly priced food. In Maguri Beel, several fish are in danger of going extinct because of pollution, habitat damage, and the introduction of non-native species, overexploitation and human activity (Moyle & Moyle, 1995; Malakar & Boruah, 2017). The 2020 oil spill incident might have had a major impact on the variety of the ichthyofauna's composition. To address the same, a comparison of the same with earlier research is desperately needed. As a result, the current study intends to examine the fish variety of Maguri Motapung Beel, close to Motapung Village in the Tinsukia region of Assam and Dibru-Saikhowa National Park.

INTRODUCTION

The aquatic ecosystem is highly dependent on water quality and biodiversity. The water quality parameters play an important role in the biology and physiology of fish (Dhawan and Kaur, 2002). Fish communities are an important aspect of the aquatic ecosystem. Moreover, they also serve as an indicator of the quality of the aquatic ecosystem (Sharma et al., 2014). Ramsar Convention on wetlands in 1971, characterized wetlands as "Areas of Marsh, fen, peatland, whether natural or artificial, permanent or temporary with water that is static or flowing, brackish or salt, including areas of marine water the depth of which at low tide should not exceed". At the surface, freshwater serves as a habitat for numerous species and comprises a substantial portion of Earth's biological diversity. Wetlands cover approximately 6.4% of the Earth's total surface area. Being a large biodiverse region, India accounts for 11.72% of the world's fish diversity and 40% of fish live in freshwater ecosystems (Kar et al., 2006, Balasubramanium, 2017). Fish are key species that determine the distribution and abundance of other organisms and have a significant impact on the ecosystem and are considered good indicators of water quality in the ecosystem (Moyle and Leidy, 1992). Assam, located in the northeastern region, possesses extensive and diverse freshwater resources, earning it recognition as one of the richest biodiversity sites in India. There are 2,500 species of fish in India; 930 of them live in fresh water and 1570 in the sea (Kar, 2003). The entire northeastern region, including Assam, has large and diverse freshwater resources and is considered one of the richest biodiversity hotspots of India. The NE region has unique topographic conditions and is blessed with large and varied water resources in the form of rivers (19,150 km); swimming pools (23,792ha); lakes and marshes (143,740 ha); ponds and mini-dams (40,808 ha) and shallow spawning systems paddy with fish farming systems (2780 ha) (Mahanta et al., 2003). This region of the country is very diverse in terms of fish. So far, 267 freshwater fish species belonging to 114 genera 38 families and 10 orders have been reported from the region (Mahanta et al., 2003). A total of 266 species belonging to 114 genera under 38 genera and 10 orders have been reported from the Northeast including Assam (Sen, 2010). A survey of the fish fauna of the Brahmaputra in Assam revealed 41 commercially important species (Talwar and Jhingran, 1991). Assam has 1,392 beels in over 100,000 hectares, which constitutes 61 percent of the state's lentic water supply. Water is one of the most important compounds in the ecosystem. Better water quality is characterized by its physical, chemical and biological characteristics.

INTRODUCTION

The genus Pallisentis was erected by Van Cleave, 1928 with P. umbellatus as its type species. The other species reported under this genus are P. gaoes (Mac Callum, 1918) Van Cleave, 1928; P. cleatus Van Cleave, 1928; P. ophiocephali (Thapar, 1930) Baylis, 1933; P. nagpurensis (Bhalerao, 1931) Baylis, 1933; P. nandai Sarkar, 1953; P. colisai Sarkar, 1956; P. basiri Farooqi, 1958; P. allahabadi Agarwal, 1958; P. buckleyi Tadross, 1966; P. pandei Rai, 1967; P. guntei Sahay et al., 1967; P. garuai n. comb. Davendrosentis garuai Sahay et al., 1971; P. magnum (Saeed & Bilqees, 1971); P. tetradontae Troncy, 1978; P. clupei Gupta and Gupta, 1979; P. cavasi, P. fasciati, P. gomtii Gupta and Verma, 1980; P. indica, P. croftoni Mithal and Lal, 1981; P. kalrai Khan and Bilqees, 1985; P. guptai, P. mehrai Gupta and Fatma, 1985; P. fotedari Gupta and Sinha, 1991 and P. jagani Koul et al., 1991.

MATERIALS AND METHODS

The fish hosts were collected from the study area and brought to the laboratory for parasitic examination. The external body surface as well as the internal body organs were thoroughly examined for the parasites. The collected acanthocephalan parasites were washed and relaxed in normal saline. Then the specimen was fixed and preserved in AFA (alcohol-formalin-acetic acid) solution. To facilitate identification of the worms the parasites were cleared in lactophenol and mounted in glycerine jelly. Diagrams were made with the help of camera lucida and measurements were taken with ocular micrometer. All the measurements are in millimetres. The collected parasites were identified following Yamaguti (1963) and Bhattacharya (2007).

INTRODUCTION

Lakes are of immense ecological, economic, and cultural significance, representing integral features within our planet's landscapes. Studies show that there are around 117 million lakes worldwide, constituting about 4% of the Earth's non-glaciated land surface (Verpoorter et al., 2014). These lakes play a crucial role in providing essential services to nearby communities and serve as important centres for recreation and overall well-being. However, the increasing demand for natural resources has led to widespread degradation of these lakes (Jenny et al., 2020). Despite efforts to restore lakes, there is a prevailing perception that such programs often encounter high failure rates (Søndergaard et al., 2007; Gulati et al., 2008; Poikane et al., 2024). This concern is particularly pronounced in less economically developed countries, where populations are highly exposed to the consequences of lake degradation, and monitoring, assessment, and restoration programs may be in nascent stages. Additionally, lakes play a pivotal role in climate regulation, influencing local weather patterns and contributing to global processes such as water and carbon cycles. Recognizing and preserving the significance of lakes is imperative for sustaining ecosystems, ensuring water security, and nurturing the well-being of both the natural environment and human societies. 21o 8’ 55’’ 79o 4’46’’E.

Nagpur situated at coordinates 21o 8’ 55’’ N and 79o 4’46’’E, holds the distinction of being the second capital of Maharashtra. Renowned as the "orange city" and the "city of lakes," Nagpur relies significantly on its lakes as a valuable resource base. The current water supply for the city is primarily sourced from, Kanhan River, Gorewada Lake, and Pench Dam. Futala Lake serves an irrigation purpose, benefitting 84 acres of cultivated agricultural land. Ambazari Lake, on the other hand, caters to the water needs of local residents in the MIDC colony, Hingna area, Nagpur, and supports industrial purposes. Other notable water bodies in Nagpur include Sonegaon, Gandhisagar, Naik, Sakkardara, and Lendi. However, these lakes face severe pollution due to anthropogenic activities such as bathing, washing clothes, and improperly disposing of plastic, paper, oil, and worship materials. Moreover, the lakes Gandhisagar and Lendi are now dried.

INTRODUCTION

Heterotrophic organisms, such as zooplankton, use phytoplankton as food, regenerating nutrients through metabolic processes and transferring energy to higher trophic levels. Zooplankton are involved in the conversion of waste matter into animal food that may be consumed, in addition to helping to shift food from the primary to the secondary level. These species act as a bridge in the food chain, carrying energy from the primary producers, planktonic algae, to the larger predatory invertebrates and fish that eat them (Kumari et al., 2008). Macróplankton (200–2000 μm), microplankton (20–200 μm), nanoplankton (2–20 μm), picoplankton (0.2-2 μm), and femtoplankton (0.02 0.2 μm) are the different sizes of plankton (Kumar et al., 2023).

The sensitivity of zooplankton to alterations in aquatic environments is significant. Differences in species composition, abundance, and distribution of body size can be used to identify the consequences of environmental disturbances(Joshi & Joshi, 2011). A number of variables, including temperature, sunlight, ocean currents, and nutrition availability, affect plankton populations. They are vital to ecosystems because they support carbon cycling, global biodiversity, and the general health of the oceans (Cottenie et al., 2001). An evaluation of the pollution state heavily depends on the interaction between phytoplankton diversity and environmental conditions. The diversity of algae found in the Chlorophyceae family is a key sign of the quality of the water. The differences in water quality can be attributed to a combination of natural and human-caused factors. Owing to extensive human activity, anthropogenic inputs from various sources are typically the main variables influencing the water quality of the majority of rivers, lakes, estuaries, and seas, particularly those that are next to densely populated areas(Jeyaraj et al., 2016). Living things, including plants, plankton, animals, and bacteria, are known as bioindicators, and they are used to monitor the state of the environment's natural ecosystem. They are known across the world as aquatic pollution indicator species. Every organic entity in a biological system gives information about the state of its surroundings. For example, plankton responds quickly to changes in the environment and is a valuable biomarker for determining the quality of water as well as a sign of pollution. Plankton is the best indicator of the health of aquatic flora and serves as an early warning system(Wadjikar et al., 2017). An ecosystem that is in balance is one in which beneficial interactions occur between the environment and living organisms. Since water quality is essential to maintaining an environment in balance, it is evident that it plays a crucial role in this relationship(Jeyaraj et al., 2016).

INTRODUCTION

In nature water is considered as the most important natural resource which is utilized in large quantity throughout the world for drinking, washing, bathing, recreation, irrigation, aquaculture and many industries. Water also plays a fundamental role in regulation of water cycle in nature. India is a agriculture based country totally based on different water sources. The quality of water plays a important role to mankind because it is directly linked with human health. Lake water’s are mainly used for farming and domestic activities like cloth washing. Increasing human activities continuously in lake basins is posing a great threat to all forms of life in aquatic environment. Most of the people who live in villages use irrigation facilities for farms and use excessive use fertilizers and pesticides for agriculture purposes and subsequently and degrade the aquatic ecosystems of lakes. We need to conserve water for future generations and safeguard our natural resources for sustainable development and biodiversity conservation.

Many researchers investigated the freshwater lakes and ponds in the Indian subcontinent viz. Bagde and Verma (1985), Desai (2014), Patel and Patel (2012), Nirbhavanae and Khobragade (2017), Mehta et al (2016), Gupta (2018), Bastola (2013), Raj and Sevankodiyane (2018), Rana Phul Kunwar Singh (2016), Shyamala and Hemvathy (2018), Meshram et al (2014), Fule and Nimgare (2018), Chaudhary and Sitre (2020), Pimpalshende and Sitre (2021).

INTRODUCTION

India is rich in biodiversity and possesses about 108276 species of insects. Indian subcontinent is one of the mega biodiversity countries of the world occupying ninth position in terms of freshwater mega biodiversity (Mittermeier et al., 1997) comprising 30 order (Dijkstra et al. 2013). Inland wetlands of India serve as the habitat for more than 500 species of aquatic insects which are represented predominantly by Ephemeroptera (mayflies), Odonata (dragonflies) and Trichoptera (caddisflies), (Subramanian and Sivaramakrishnan, 2007). Aquatic insects play important ecological roles in keeping freshwater ecosystems functioning properly (Choudhary and Janak, 2015). The aquatic insects are important part of aquatic ecosystem which play vital role in ecosystem functioning and are known to be representative of structure and function of freshwater ecosystem due to their high abundance, high birthrate with short generation time, large and rapid colonization (Choudhary and Ahi 2015). Aquatic insect function on multiple trophic level such as shredders, collectors, scraper and predators on animal debris, wood and leaf litter reaching the wetland from the surrounding landscape. Nutrients processed by aquatic insects are further degraded into absorbable form by fungal and bacterial action. Plants in the riparian zone absorb this nutrient soup transported through the wetlands. In addition to this significant ecosystem function, aquatic insects are also a primary source of food for fishes and amphibians (Tachet et al., 2003 ; Kumar, 2014).They interact in nutrient cycling within lentic and lotic systems and are regarded as an effective bioindicator (Lundquist and Zhu 2018) and serve as an important component of natural foodweb in aquatic ecosystem. However, the aquatic insect fauna of this part in India is inadequately documented. Therefore, present study carried out to delineate the baseline status of aquatic insects of Anandwan lakes at Warora Dist: Chandrapur.

INTRODUCTION

Wheeler bearers commonly referred to as ‘Rotifers ‘are significantly they are often taken as reliable indicators of mesotrophic characteristics in the lake ecosystems (Gannon and Stemberger, 1978). Because of their wide tolerances to varied dissolved oxygen levels and temperature distributions, they are even found to inhabit the deeper waters of aquatic ecosystems (Esparcia et al., 1989). They belong to the Kingdom Animalia, Subkingdom Eumetazoa, Phylum Rotifera (Cuvier, 1798) having three classes Monogononta, Digononta and Seisonidea (Pennak 1953). In other words these wheel animalcules named, because of the presence of their corona, which is composed of several ciliated tufts around their mouth region. This ciliated tuft helps in locomotion and resembles a wheel. These create a current that sweeps food into the mouth, where it is chewed up by a characteristic pharynx (called the mastax) containing a tiny, calcified, jaw-like structure called the trophi. The cilia functions to pull the animal, when unattached, through the water. Most free-living forms have pair of posterior toes to anchor themselves while feeding. Rotifers are bilaterally symmetrical found in various shapes. There is a well-developed cuticle, thick and rigid, providing a box-like shape, or flexible, giving the animal a worm like shape; such rotifers are respectively called loricate and illoricate.

Habitats of Rotifers are relatively easy to find. Many live in ponds, moist soil, or any stagnant water. Rotifers can be free swimming or sessile. Rotifers are mostly omnivorous and some have been observed to be cannibalistic. They normally eat algae or decomposing organic material. As they are a major food source for Cladoceran , Copepodans , juvenile fishes (fry) and fishes, therefore , an important food link of water ecosystem (Arora and Mehra 2003). Presence of abundant Rotifers in freshwaters determines them to be one of the main groups of zooplankton in limnological studies. They are permanently and obligatorily connected to aquatic habitats in all active stages and only their resting stages are drought-resistant (Chopra et al 2012). Various researchers have conducted pioneer study on the diversity and habitat of rotifers such as Anderson 1889; Sharma 1987; Sharma 1998a; Gilbert and Schreiber 1998; Arora and Mehra 2003; George et al. 2011; Tyor and Chawala 2012. However such studies on Madhuganga dam water has not been conducted, hence for assessment of Madhuganga Lentic water has been conducted for the seasonal variation in diversity and density of rotifers.

INTRODUCTION

Indigenous Technical Knowledge (ITK) represents the treasure trove of wisdom held by indigenous communities, often overlooked yet immensely valuable. Its impact spans various domains, notably aquaculture, where it has been pivotal. Local fisher communities, drawing from their indigenous knowledge, have been crucial in safeguarding wild fish genetics and improving aquaculture yields. Moreover, their Indigenous and local knowledge (ILK) contributes multifaceted insights to fisheries and aquatic ecosystems science, underscoring the need to preserve and honor this invaluable heritage. Additionally, traditional indigenous systems like aub-anbars have historically demonstrated their effectiveness in practical applications such as passive cooling and water storage, further highlighting the relevance and efficacy of ITK.

Importance of ITK in Aquaculture

Indigenous Technical Knowledge (ITK) is essential in aquaculture, providing valuable methods for pond preparation, water quality management, disease control, and post-harvest operations. These traditional practices, backed by scientific validation, can greatly improve fish production sustainability while being environmentally friendly. Moreover, modern biotechnological tools are increasingly used in aquaculture to enhance fish quality, disease resistance, growth rates, and genetic diversity. Additionally, the concept of intelligent fish farms, employing technologies like IoT and artificial intelligence, aims to optimize aquaculture processes for precise feeding, disease control, and harvesting, promoting green and sustainable practices. Combining ITK with modern biotechnology and intelligent technologies is crucial for advancing aquaculture practices towards efficiency, sustainability, and increased productivity.

INTRODUCTION

The expansion of aquaculture, a vital source of income for a large portion of the global population (Salam et al., 2014), has created an unforeseen challenge: increased competition for land use with traditional agriculture. This land squeeze is further intensified by a multitude of factors. Shrinking arable land due to urbanization and desertification, coupled with the relentless growth of the human population, puts immense strain on existing agricultural resources. Man-made environmental pollution from industrial waste and agricultural runoff, along with the far-reaching effects of climate change, add another layer of complexity. These combined pressures necessitate a paradigm shift towards innovative and sustainable agricultural practices.

One promising solution gaining traction is aquaponics, a system designed to cultivate plants and aquatic animals together in a carefully balanced, recirculating environment (Salam et al., 2014). This approach leverages a symbiotic relationship between fish and plants. Fish waste, rich in nitrogenous compounds, acts as a natural fertilizer for the plants growing in the system. These plants, in turn, function as biofilters, removing excess nutrients and purifying the water for the fish. In essence, aquaponics integrates two established agricultural techniques: intensive aquaculture, the practice of raising fish in controlled tank environments, and hydroponics, the cultivation of plants without soil (FAO, 2012). The aquaculture component of aquaponics utilizes eco-friendly, indoor recirculating systems that enable meticulous control over water quality and temperature year-round. This controlled environment offers significant advantages over traditional methods, minimizing dependence on external factors like weather patterns.