eChapters

23.1 Introduction

Excretion is the elimination of nitrogenous metabolic wastes from the gut and skin of the body. Through excretion, certain substances are removed while others are conserved. Fish are either ammonotelic or ureotelic animals. Kidneys play the most important role in excretion to maintain water-salt balance.

Fish gill ammonia excretion has been investigated for 80 years, but its mechanisms are still up for debate. A new paradigm has been established by the relatively recent identification of the ammonia-transporting role of the Rhesus (Rh) proteins, a family related to the Mep/Amt family of methyl ammonia and ammonia transporters in many living organisms. These proteins also occur as glycosylated proteins in fish gills (Wright and Wood, 2009).

24.1 Introduction

Water is a universal biological solvent and the medium in which most of the cellular reactions of metabolism occur. Fish contain a large amount of water in their cells and extracellular fluids. It is important to a fish that its water content be nearly constant. This more or less steady state of water content in the body can only be maintained when there is a quality difference between the amount of water entering and leaving the body. The process of regulating the movement of water and its volume in the body is known as osmoregulation.

25.1 Introduction

All fishes have a similar nervous system organisation. Meninx primitive is a single protective covering that covers the brain and spinal cord. The brain varies in size about the body in different species and does not occupy the entire cranial cavity (Fig. 25.1).

25.2 The Brain

Except for elasmobranchs, which have larger brains, the relative ratio of the brain has been observed to be fairly constant in all fishes. The brain-body weight ratio, also known as the cerebro-somatic index (CSI), is calculated as follows. 

Endocrine glands secrete their products into the bloodstream and body tissues in conjunction with the central nervous system to control and regulate a variety of body functions (Fig. 26.1). Various endocrine glands described below have been discovered in fish that are associated with various tasks and functions.

26.1 Pituitary Gland

26.1.1 Introduction

The pituitary gland (=Hypophysis) is a central and discrete organ of the neuro endocrine system in fish playing critical roles in various physiological processes such as stress response and behaviour.

Fishes use their sense organs to detect their bodies and their environment. Sense organs include the eyes, the lateral lines, the nostrils, the olfactory organs and the taste organs. Each of these sense organs is equipped with sensory nerve endings. Most fish possess highly developed sense organs to detect smell, sight, hearing, taste, touch, temperature, etc.

27.1 Olfaction in Fishes

27.1.1 Introduction

28.1 Introduction

The use of biological light in active transport, nerve transmission, and muscle contraction is a feature shared by all living organisms. Surprisingly, a large number of living organisms have evolved the ability to convert chemical energy into light, which is manifested as bioluminescence.

Bioluminescence is a fascinating biological phenomenon found in both terrestrial and aquatic living organisms. The light emitted by living organisms as a result of chemical reactions in their bodies is known as bioluminescence. Cold light is produced by this type of chemiluminescence.

Fishes are generally unisexual and reproduce by several methods. Some families (Sparidae and Serranidae) are hermaphrodite also. Alz (1964) reported that in certain species, hermaphrodism becomes a normal way of life. In hermaphroditic f ishes, self-fertilisation is a common process. Parthenogenesis could have been produced experimentally (Austin and Walton 1960). There maybe a few secondary organs that increase reproductive fitness. The genital papilla is a small, fleshy tube behind the anus in some fishes, from which the sperm are released; the sex of a fish can often be determined by the shape of its papilla.

30.1 Introduction

Sexual dimorphism is a condition in which sexes of the same species exhibit morphological differences that are not directly related to reproduction. It is a common and noticeable feature of the animal world. It is extremely important in biodiversity assessments, as well as in biometry, breeding biology, induced breeding, breeding, pheromone biology and other related fields.

31.1 Introduction

Courtship is the behavioural interaction that occurs between males and females before, during and just after mating. It encompasses all expressive movements associated with pair formation and mating. “Courtship is the heterosexual communication system that leads to the consummatory sexual act,” says DeMorris. Arthropods, mollusks, fish, reptiles, and mammals are the most affected. It consists of various activities and serves a specific purpose. Many courtship activities ensure that people only mate with people of their species. The distinction between species’ courtship behaviour allows females to identify males of their species. It is concerned with reproductive fitness and provides opportunities for survival

32.1 Introduction

Development or embryogenesis refers to the events that occur after fertilisation. Embryogenesis in fish includes the formation of stages up to fingerlings. The process is similar in all fishes, but there are some differences between teleosts and elasmobranchs. The development of telolecithal eggs in fish begins soon after sperm fertilisation.

33.1 Introduction

World fisheries face the threats of overfishing and climate change that have resulted in the extinction of genetically unique stocks and loss of genetic diversity. Genomics has brought new tools that can help address fundamental questions in fisheries management such as stock identification, population structure, and adaptive response to environmental change (Bernatchez et al, 2017).

34.1 Introduction

Fishes are the first aquatic vertebrates whose life cycle is largely affected by the aquatic habitat. They exhibit much variation in their social life. Some species show no attraction between males and females, conversely, some provide high social attraction and parental care. Therefore, parental care is developed for their social life and habitat.

35.1 Introduction

Age and growth studies are vital aspects of modern fisheries because this information is pivotal for fish population and management policies.

Age and growth are important factors in the study of the natural history of fish. Age determination is an ancient practice that aids in systematic studies of fish and f isheries. Age denotes the activities of the organism about its size, whereas growth can be defined as an increase in any dimension of an organism from time or age until maturation. A fish ages as it grows, and vice versa. Fish age determination is important to marine resource management.

36.1 Introduction

Migration refers to the long-distance movement of fish from one location to another in search of food or breeding. It involves a temporary or permanent absence from one’s home range and the establishment of a residence in another. It is one of the most remarkable and fascinating characteristics of fish. It is the mass movement of fish from one body of water to another. It entails longer-duration movements of schools of fish than those seen during normal daily activities.

37.1 Introduction

Temperature describes the kinetic energy of the gases that make up air. As gas molecules move more quickly, air temperature increases. Among several environmental changes, increased air temperature affects the water cycle by increasing water temperature, which causes changes in local weather, water quality and river bodies (Gossiaux et al., 2019). This is because the water temperature is one of the most important factors for physicochemical properties of water quality (Szumiriska et al., 2020), aquatic habitats (Duggals et al., 2018), spawning rates (Besson et al., 2016) and fish growth (Collas et al., 2019) (Fig. 37.1).

38.1 Introduction

To fishery management, understanding the abundance of a given species population is critical to the success of that species’ fishery. In this context, a fish population is a naturally occurring stock of a race of fish that occupy a specific area of space and act as a biological unit. The density of the fish population, on the other hand, is the population size per unit of space.

39.1 Introduction

Like all other animals, fish are also subjected to certain diseases. This is one of the most important problems confronting a fish culturist. Diseases at times may take the form of epidemics. The occurrence and magnitude of infections and diseases are closely related to the sanitary conditions prevalent in the water and also the general health of the fish.

40.1 Introduction

India has an 8,118-kilometer-long coastline that stretches through nine Maritime States (Gujarat, Tamil Nadu, Kerala, West Bengal, Maharashtra, Odisha, Andhra Pradesh, Karnataka, and Goa) and four Union Territories (Daman and Diu, Puducherry, Lakshadweep Islands, and Andaman and Nicobar Islands). The country also has a Continental Shelf of 0.53 million km2 and an Exclusive Economic Zone (EEZ) of 2.02 million km2. The EEZ’s annual potential yield is estimated to be 3.93 million tonnes of fish.

41.1 Introduction

Fishes adapted to live at a temperature ranging from 10-200C constitute coldwater f ish. Upland water at high altitudes in the mountains and spring water at low elevations in temperate regions remain cooler than the rest, allowing coldwater f isheries to thrive in these areas. Such bodies of water, which include several hill streams, pools, lakes and reservoirs, are abundant in the Himalayan and Deccan plateau regions of peninsular India. These are fed by either melting snow or springs in the north or rain on the Deccan plateau.

42.1 Introduction

Several fish species including their seeds, eggs and spores have been imported either occasionally or artificially and introduced into the water of our nation. These fishes are not native to our country and are called exotic fishes. Based on utility, these fishes include food fishes, game fishes and larvicidal fishes. In other words, the fish species that are not of Indian origin but transplanted into Indian water for cultural purposes are called exotic fishes. Exotic fish are an alien species that are non-indigenous having their origin in another country

43.1 Introduction

Game fish (also known as sport fish or quarry) are freshwater or saltwater fish that are pursued by recreational anglers or fished with a rod and line from clear running water (Hora 1943). Some game fish (such as salmon and tuna) are commercially targeted. In other words, game fish are fish caught for sport or subsistence. Trophy f ish are game fish that are larger and heavier than the average for the species.

44.1 Introduction

Ornamental fish are a diverse and colourful species benefiting millions of aquarium enthusiasts. The term "ornamental fish" was first coined in the early 19th century to describe fish kept solely for decorative purposes by ancient civilizations such as the Sumerians and Egyptians.

They are known for their shapes, sizes, vibrant colours, intricate patterns and distinct behaviours with hobbyists and collectors. They are widely used to distinguish between fish kept for food or other practical purposes.

45.1 Introduction

Mosquitoes of various species breed in ponds, swamps, gutters, and other bodies of stagnant water, carrying parasites that cause malaria, filaria, dengue fever, chikungunya, Japanese encephalitis, Zika and yellow fever. Various approaches have been used to control mosquito populations to reduce the incidence of vector borne diseases, including chemical, physical, and biological measures. In all types of habitats, biological control against mosquito vectors is safe, friendly, and cost effective. Mosquito biological control entails introducing natural enemies such as parasites, disease organisms, and predatory animals into the environment.

46.1 Introduction

Since humans settled and flourished adjacent to the aquatic bodies and therefore f ishes might have attracted their attention. The increasing population has threatened mankind variously amongst which, the most important one is the food problem. Fish being a valuable and easily available source of food can be used to overcome the food problem to a certain extent. Indian rivers are the major source of irrigation systems, drinking water and fish as food. The fish industry of West Bengal and Orissa is some 1500 years old and in West Bengal, every family traditionally has at least one small or moderate-sized pond.

47.1 Introduction

Fish are one of the most important groups of vertebrates and have always been a significant species in man’s life, influencing it in a variety of ways. Fish are highly valued in human civilization for their food, cooking, and nutritional value. They have significant economic, nutritional, medicinal, industrial, aesthetic and religious values, and they employ millions of people worldwide. Several species are sought after as luxury foods in high-end restaurants. They help to ensure food security in many parts of the world by serving as a valuable supplement to varied and nutritious diets.

Worldwide, agriculture is the foundation of early human civilization. Humans transitioned from hunting and gathering to farming when they settled near rivers. As a consistent source of food, agriculture aided in human evolution. From then on, the economy has been sustained by agriculture. Among other things, illnesses and natural disasters frequently have an impact on agriculture. Such a state required advisory. This explains the existence of the agricultural extension domain. A social innovation, agricultural extension has been copied, altered, and developed over the years.

Introduction

It is said that Rome was not built in a day. Similarly, Extension was not master minded by one individual; rather it evolved through hard work of extension professionals around the world over more than a country.

The necessity of a human being is food, for which he must rely on agriculture. The agriculture to achieve its expected growth must depend on several factors which include technology, research and obviously extension. The basic function of agricultural extension is to train, teach and guide farmers. Agricultural extension’s primary role is to mentor, instruct, and train farmers.

Concept of Education

Education is derived from the Latin terms Educare (Educere) and Educatum. The word “educare” means to train, nourish, or shape. “Educere” means “to lead froth, to pull out.” The Latin term “Educatum” refers to the act of teaching. “Shiksha” and “Vidya” are two significant Sanskrit words that stand out as equivalents of English education. Shiksha is a word derived from “Shah,” which means “to control or discipline.” The term “Vidhya” is derived from the word “Vidh,” which means “knowledge.” During the ancient schooling period, the most essential aspects of human personality were discipline and knowledge.

Introduction

The definition of the teaching-learning process, also known as the education process, is a methodical, planned sequence of events that both the teacher and the student follow in order to accomplish the goals of teaching and learning. In primary education, values education is taught through games. Extension services are vital to the global rural and agricultural communities because they spread knowledge, offer useful skills, and encourage sustainable practices. The teaching and learning process, a dynamic exchange between extension agents and community members with the goal of enabling people to better their lives and livelihoods, is at the centre of these extension efforts.

Introduction

Planning is a “dynamic act of reflecting about, thinking about, and choosing among various options regarding the goals and objectives and the route to journey i.e. educational experience, we should follow to reach those destinations” (Forest and Baker, 1994). It offers opportunity to people to “participate” and “contribute” in the process. Therefore, it is understood that “planning extension programs has become an increasingly accepted practice among national authorities” (Maalouf, in Rivera, 1987, p. 116 as cited by Cristovao et al?, 1997).

Rural Development Concept

Rural development falls under the wider concept of “Development,” a goal universally valued by individuals, families, communities, and countries around the globe, regardless of its definition.

Rural development encompasses a wide scope, primarily targeting actions to enhance underdeveloped aspects of village economies. Key areas in rural India that require new development initiatives include- enhancing human resources, focusing on literacy (especially among women), education, skill enhancement, health, sanitation, public health improvements, and land reform, alongside the advancement of each locality’s productive assets.

Introduction

Rural development programmes are designed as an integral part for socio economic development, especially of developing country like India. These rural development programmes connotes greater social transformation which has recognized as a sine qua non. Since from independence, rural development programmes mainly focusing on poverty reduction (Dev, 1995). The number of public and private organizations focus on rural development as a way to poverty1 reduction has grown up with the comprehension that most impoverished people lives in rural and tribal areas.

Introduction

What is community development?

Community development refers to the process of bringing community people together after identifying issues related to them and taking a collective action. Community development empowers residents and builds stronger, more integrated communities. Community development is an all-encompassing approach based on the ideas of empowerment, human rights, inclusiveness, social justice, self-determination, and collective action (Kenny, 2007).

Introduction

Leadership as such has a broad connotation per se. It is an interesting social phenomenon. It could be stated that leadership is a part of the power structure and any form of group life can be traced back to some form of leadership. Stogdill (1950) said that the word “leader” originated back in the 1300s and the word “leadership” in the 1800s (Muhammad and Sameen, 2019). Different authors have given different definitions and outlooks at different times. “There are almost as many different definitions of leadership as there are persons who have attempted to define the concept” (Bass, 1990).

Introduction

To accomplish the objectives of the organisation, the administration often performs a standard set of tasks. Administration is the direction, leadership, and supervision of a group’s actions toward certain common objectives (Newman, 1950). It suggests sincere efforts made to plan and manage human activities in order to accomplish set or desired goals. Organising, leading, and controlling people and resources to achieve predetermined goals.

Introduction

The interest in technology transfer traces back to the colonial era, which began by disseminating knowledge about the core industries of mining, plantations, and agriculture, which was seven decades ago. Technology has had a significant impact on human development and life growth throughout history. People’s life are constantly changing due of technology, whether or not they are ready for it. There has been so much change brought about by technology, and it has occurred at such a rapid pace that many times people lose their capacity to handle it successfully and pleasantly. In this scenario, more ideas are being created in the smaller globe, and technology’s residence time is getting much shorter.

“Activities which develop individual knowledge, talents, skills, and behaviour and improve institutional structures and processes so that the organization may efficiently accomplish its mission and goals in a sustainable manner” it refers as a capacity building. One of the crucial elements of capacity building is training.

Training for Development

Training is becoming an integral component of HRD. It has developed into one of the elements that allows any institution to produce its personnel who are the most productive and qualified.

Information and Communication Technology: Concept

ICT refers to an extensive array of systems and technologies dedicated to managing and delivering information and facilitating communication. This includes digital platforms such as the internet and the World Wide Web, as well as traditional media like radio, television—through cable and wireless methods—mobile phones, and printed materials. Accompanying these technologies are services and applications such as videoconferencing and online learning that utilize these mediums.

Introduction

The ‘cutting edge’ of any development is the projects. No matter how well planned, a poorly executed project will waste valuable resources. India has pioneered many poverty-reduction programmes in agriculture, rural development, health and family welfare, education, women’s and children’s development, drinking water, and other fields. According to an analysis of these initiatives, monitoring and suitable mid-course corrective measures are crucial to accomplishing project objectives.

The 1980s and 1990s saw a few shifts in how we view development. There has been a significant ideological change in favour of privatisation. Since the 1990s, there has been an increase in the participation of the private sector (which deals with agro-inputs, agribusiness, and financial services), non governmental organisations (both local and international), producer groups, cooperatives, and associations, as well as independent and connected to or employed by agri-business/producer associations consultants and ICT (Information and Communication technologies) based services.

Introduction

In the animal kingdom, there are many animals with a concrete social system in their ranks. Animals like lions, wolves, and apes have complex social systems in their lives. And what is the most important thing in a functional social system? It’s communication! Communication is the most important function in any social system, which binds that system.

And what organism has the most complex social system? It’s humans. Thus, the human social system requires a very complex communication system.

Introduction

Agriculture plays important role in boosting economic activity of farmers. Since it transfers new technologies within the knowledge and information system, it has special features related to knowledge, innovation, and those three. Agribusiness farming needs the diffusion of innovation. Many farmers were unable to boost their earnings. The development of the agribusiness and the welfare of the farmer were both significantly influenced by innovation. Diffusion includes three fairly distinct processes i.e. presentation of the new culture element or elements to the society, acceptance by the society, and the integration of the accepted element or elements into the pre-existing culture (Linton, 1936).

Introduction

Diffusion is the process by which an innovation is transmitted to the members of a social system over some time and through channels in a specified manner. According to Rogers (1962), this is a unique form of communication in which the messages are focused on innovative concepts. The concepts can include (i) A new idea, (ii) An idea that is communicated via certain channels (iii) Among the members of a social system (iv) Overtime. On the other hand, the adoption process is the mental process through which an individual passes from first hearing about an innovation to final adoption, as defined by Rogers (1962).

Meaning and Definitions

Agricultural journalism refers to the specialized field of journalism focused on reporting, analyzing, and disseminating information related to agriculture, farming, rural development, and related topics. It plays a crucial role in educating and informing the public, policymakers, and stakeholders about the agricultural sector, its challenges, innovations, and contributions to society.

Here are a few definitions of agricultural journalism.

Introduction

The emergence of the green revolution highlighted the significance of agricultural communication. Its strategy and attitude were modified to reflect the priorities of contemporary agriculture. Earlier attempts at agricultural journalism drew their power mostly from agricultural extension rather than journalism or mass communication. The primary objective was to provide farmers with a collection of techniques authored by scientists or subject matter experts about a variety of crops. Due to the lack of synergy between journalism and extension, agricultural journalism stalled for many years..

1.1 Introduction

The greenhouse industry is rapidly growing, particularly in mild climates, and is crucial for providing access to fresh and clean food. Greenhouses provide an optimal climate for crops to grow and protect them from outside pests. Furthermore, greenhouse production has the potential to reduce water waste and implement integrated protection and production (IPP). It is essential to consider the environmental impact of protected cultivation, and Life Cycle Assessment (LCA) is a valuable tool for evaluating these impacts.

2.1 Introduction

Greenhouses are used mainly for cultivating vegetables and fruits during the off-season to provide favorable growing conditions. Proper management of the greenhouse structure is necessary to create these off-seasonal favorable conditions for plants. Factors like site selection, location, atmospheric conditions, cropping pattern, and structure of the greenhouse are considered during the development of a greenhouse. The National Committee on the use of Plastics in Agriculture (NCPA-1982) suggests conducting site-specific greenhouse technology trials before implementation across the nation.

3.1 Introduction

Greenhouses are buildings with a controlled environment that facilitate plant culture and development. They offer protection from adverse external weather conditions, high temperatures, strong winds, and pests, while providing an ideal environment for plant growth. The construction of a greenhouse involves the use of various materials to ensure its structural stability, longevity, light transmission, and insulation. The different components of the greenhouse, such as the frame, flooring, and covering, are constructed using different materials such as wood, aluminum, steel, concrete, soil, gravel, and more.

4.1 Introduction

Experts predict that the global population will exceed 9.6 billion by 2050. This, coupled with the rise of urbanization, the scarcity of arable land, and the destructive effects of climate change, poses significant challenges for agriculture and food production worldwide. To combat these challenges, new horticultural research techniques must be implemented to enhance productivity and efficiency, improve nutrition, and ensure food security, especially during times of crisis like the COVID-19 pandemic. Greenhouse technology has made remarkable strides in recent years, allowing for the manipulation of internal growth elements like temperature, light intensity, and CO2 concentration to create optimal growing conditions

Solar heat plays a pivotal role in the functioning of greenhouses, serving as a primary energy source that influences the internal climate crucial for plant growth. The absorption of solar radiation by the greenhouse covering material initiates a complex process of heat transfer, involving conduction, convection, and radiation. This solar energy, once absorbed, contributes to elevating the temperature within the greenhouse, creating a favorable environment for plants. A fundamental understanding of solar heat dynamics is essential for optimizing greenhouse design and operational efficiency.