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According to the facts, groundwater salinization and the scarcity of freshwater are indeed expanding. In the coming decades, saline water will replace freshwater as the principal resource for agriculture and aquaculture. Over 8.62 million hectares of land in India and over 397 million hectares of land worldwide have been rendered unusable for traditional agriculture as a result of secondary salinization. Use of salinized land and the water resources for aquaculture is a flexible solution to reduce environmental problem with multiple potential benefits on the economic, social, and environmental fronts. As aquaculture demand has increased, new production methods have been developed. Inland saline aquaculture, here defined as a land-based aquaculture system using saline groundwater and surface water, is practised by a number of countries, including Israel, USA, India, and Australia. The possibility that saline groundwater may differ chemically from coastal seawater is one of the key barriers to the growth of inland saline aquaculture. One must either change the chemistry or choose species that can tolerate the fluctuations to get around this. Several species are farmed or evaluated for their potential including finfish like tilapia, Indian Major Carps, catfishes, climbing perch, Asian sea bass, cobia, milkfish, mullet, and sturgeons. By combining the usage of resources, cultural systems play a significant part in attaining the disruptive technology of inland saline aquaculture. This review revealed the finfish species raised in inland saline resources as well as culture methods such as pond-based, tank-based, biofloc, and aquaponic systems for inland saline aquaculture. One of the cutting-edge food production methods required to boost aquaculture productivity and meet the expanding seafood demand is inland saline aquaculture. In spite of this, inland saline aquaculture has yet to become an industrial-scale and rural business to produce sustainably from unutilized lands.

Introduction

The global population is expected to reach 10 billion by 2050, with seafood making up about 15% of the animal protein consumed, averaging 20.2 kg per person in 2020 (Boyd et al., 2022). Due to the overfishing of fish stocks, estimated at 93.8%, aquaculture is seen as crucial to meet future seafood demand (FAO, 2022). Aquaculture offers a promising solution to food security challenges by leveraging our oceans, seas, and freshwater bodies to produce healthy and nutritious food. However, it's worth noting that aquaculture has been linked to the loss of mangroves, with shrimp farming accounting for 38% of historical global mangrove depletion (Friess et al., 2019).

Mangrove forests play a crucial role in supporting diverse ecosystems and providing essential services, primarily in tropical and subtropical coastal areas where they thrive in intertidal zones. However, these same areas are often utilized for aquaculture activities, leading to significant mangrove forest conversion. For instance, aquaculture has been responsible for converting approximately 5,44,000 hectares of mangrove forests in eight tropical countries (Hamilton, 2013). To address the challenge of balancing mangrove conservation with aquaculture production, integrated mangrove aquaculture (IMA) has been proposed. IMA involves planting mangroves within or alongside shrimp or f ish ponds. However, it's important to note that mangroves within IMA shrimp systems typically do not provide the same level of biodiversity and ecosystem functions and services as intact mangrove forests.

Crabs are one of the fast-growing animals from phylum arthropod. Freshwater crabs is now becoming as an important shellfish in freshwater aquaculture production due to its delicacy and nutritional richness. Freshwater crabs are considered good for human consumption and economically important crustacean in many developing countries such as India, China, Nigeria, Japan etc. Freshwater crabs are distributed in the tropical region of the world and they spend their entire lives in freshwater. In Indian territory Western ghats of Maharashtra and north east part of India are considerably more diverse in freshwater crab biodiversity. While only freshwater crab species Barytelphusa cunicularis is commonly observed all over India. In Maharashtra Kolhapur and Konkan region stands out for well-established crab market, driven by high freshwater crab consumption. Freshwater crab serve as good protein food, lipid and cheap carbohydrate source as well as valuable mineral source for human consumption particularly tribal and poor people. Freshwater crab aquaculture, like other types of aquaculture practices, offers a wide range of culture systems, extensive monoculture to intensive monoculture. In freshwater crab aquaculture crab farmers mainly prefers Barytelphusa cunicularis as a culture species.

Introduction

In the 21st century aquaculture has become one of the most important booming industries in the world. With just a mere contribution to the worlds fish production in 1960’s, and able to contribute to about nearly 50% in 2021, production from aquaculture has increased manifolds. Successful aquaculture relies on creating a suitable environment for growth of aquatic animals. Water quality has to be the most important component for successful aquaculture production. Throughout the farming period, it is necessary to maintain good water quality to ensure high survival and fast growth of cultured species. There are numerous water quality parameters that can impact the well-being of fish and crustaceans, most of which are discussed in this chapter.

Factors like salinity and water temperature play a critical role in assessing the suitability of a location for the cultivation of specific species. Additionally, factors such as alkalinity, turbidity, phosphorus, and nitrogen hold significance due to their impact on plant productivity, which, in turn, affects aquaculture production. As the cultivation progresses, factors like dissolved oxygen, carbon dioxide, ammonia, and others gain importance, as they have the potential to create stress for the cultured animals. This chapter offers an overview of the presence and behavior of each of these variables in both natural water environments and aquaculture ponds.

With constantly increasing population and need for food security in the present era, an alternate option to safeguard the nutritional well-being of human civilisation is the utmost necessity of the hour. Aquaponics is a system which combines two food-producing systems such as a recirculatory aquaculture system and hydroponics in such a way, that, the waste of one system is utilised in the other system making it a perfect example of the eco friendly model. This system is a soil-less system which can be set up in small vicinity, providing higher outputs. The designs can be changed according to one’s needs, but the main components of the unit should be kept in mind. The main components consist of a fish tank, mechanical filter, biological filter, hydroponics unit along with sump. Although the hydroponics unit are of various kinds but broadly it can be classified into three main types-1. media bed, 2. Nutrient film technique and 3. Deep water culture. If there is a scarcity of land and water or if the quality of soil is poor, usage of aquaponics will be sustainable.

Introduction

Aquaponics is a combination of hydroponics with recirculatory aquaculture system(RAS) as a single production system. Water with fish wastes coming from the fish tank circulates and passes through the filters, the plant grows on beds and water recycles back to the fish tank in an aquaponic system. At f irst solid waste are removed by mechanic filtration followed by biofiltration for removal of dissolved wastes. Ammonia, which is poisonous to fish, is converted to nitrate, a more readily available fertiliser for plants, by bacteria in the biofilter. The plants absorb nitrate and other nutrients when the water passes through plant growing beds, filtering it prior to its arrival in the fish tank.

Sustainability Issues Regarding Major Marine Raw Materials Used in Aquaculture Diets

In 2018, more than 70% of the fish production is from fed aquaculture where f ish meals (FMs) and fish oils (FOs) are the main marine raw materials used in aquaculture diets or fish feed (Hua et al. 2019). They are derived or reduced products from the catch of small, pelagic, low-priced marine fish (forage fish) like Peruvian anchoveta that are rich in protein, micronutrient and lipid and are commonly termed as the ‘feed grade marine fishery’ (Bell and Waagbø, 2008; Bendiksen et al. 2011). The whole fish or any other f ish processing by-products are either cooked and then pressed to produce a liquid which on centrifuging produce the fish oil or are dried and crushed into powder-like material which is called as the fish meal (FAO, 2020). FM has the enough balance and concentration of essential amino acids and FO are rich in n-3 essential fatty acids especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). FM and FO are the main ingredients in aquaculture diets as they are relatively cheap, readily available, accepted and digested by the fish. The highest amount of these ingredients are often used in feeds for the high value aquatic organisms like carnivorous finfish (eg: Dicentrarchus labrax, Rachycendron canadum) (mostly marine), eels, salmonids, trouts, marine shrimps and freshwater crustaceans (see figure 1) etc. (Houlihan et al. 2001; Halver and Hardy, 2002; Miller et al. 2008) which are mainly imported by prosperous countries adding to good seafood trade value. All the intensive aquaculture production systems like recirculatory aquaculture systems, raceway aquaculture systems, aquaponics, cage culture, shrimp ponds etc are the major end users of the marine raw materials.

Introduction

In the face of a burgeoning global population, the imperative for robust advancements in food production, especially within the aquaculture industry, is more pressing than ever. The expansion of this industry necessitates a nuanced consideration of environmental, economic, and social factors underpinned by a commitment to sustainable development. However, the intensification of aquaculture, particularly in coastal regions, poses long-term environmental risks due to increased organic matter in water, demanding innovative solutions.

In recent decades, recirculating systems have emerged as a step toward sustainable aquaculture, offering an effective approach to control wastewater. High operating costs have hindered widespread adoption despite their potential, particularly in developing countries. Enter the need for a game-changing, cost effective, and environmentally friendly technology that resonates with farmers on a large scale. This is where the Biofloc system, or Biofloc technology (BFT), takes center stage. A beacon of cost-effectiveness, sustainability, and environmental friendliness, the BFT reduces water exchange to almost zero and slashes artificial feeding ratios. This revolutionary system enhances water quality and generates microbial protein for aquatic species, addressing critical challenges faced by the aquaculture industry.

Introduction

In aquaculture practises carried out in open environments (e.g. ponds, cages and pens), natural interaction between the culture and non-culture species, where the culture species are been fed by the non-culture species (predation) can occur, causing significant economic loses (Ross, 1988). As many as thirteen different predators are considered to cause loss or damage on salmon farms in Scotland alone among which cetaceans are notable. Seals, sea lions, aquatic birds, dolphins, whales, otters, crabs, starfish, snail, snakes, rats etc are generally considered as predators (SSGA, 1990; Miron et al., 2005), but cetacean species are not notable predators within salmon farms. It is necessary to develop an environment friendly and economically feasible methods or technologies to limit the useless natural interaction. Manual chasing away or removal of predators, usage of scarecrows, anti-predatory nets, covering nets and increasing the tension of nets are some methods used to prevent predations in different aquaculture scenarios.

Acoustic Deterrent Devices (ADDs) otherwise called as Acoustic Harassment Devices (AHDs) help to prevent predation as they produce strong underwater noises (sound waves) that disturb and scare off the predators (Gordon & Northridge, 2002). AHDs are comparatively higher energy output devices than ADDs that operate at a power level of above 185 dB re 1µPa @1m. However, as the hearing threshold of different predators differ, the term “ADDs” are generally used for those that are efficient to deter the predators irrespective of their operating power levels (Götz & Janik 2010). One of the first usage of different unspecified sounds (eg: killer whale’s recorded voice) to deter predators (seals) were during the 1970s and no sounds were then found efficient in a long-term run (Anderson and Hawkins, 1988). Later through the 1980s, the precursor of modern ADDs (175-210 dB re 1uPa @1m) that emit out sound waves of frequency range (8-17 kHz), which is similar to the predator’s (seals) most sensitive hearing range were developed (Mate et al.,1987).

In the earlier chapter the major soil vulnerability namely, water and wind erosion, depletion of soil organic matter, loss of plant nutrients, salinity, alkalinity, acidity, pollution and contamination, compaction, sealing, crusting, water-logging, aridity, landslide and abandoned mines were described. In this chapter two more parts, Importance of remote sensing (RS) and geographical information system (GIS) in soils and Watershed management are also included after seeing their importance in agriculture and soils. Restoration means that by various actions or processes to return something to its original owner, site, place, or condition. In this context our aim is to restore our mother soil from various vulnerabilities by different actions and processes to its natural and original condition up to the maximum possible extent. Management is defined as the scientific methods to attain targeted production through planning, organising, training and fixing targets for employees. Therefore, after the restoration, soils should be managed according to scientific method of action by scientifically selected and trained staff to perform the assigned responsibilities, effectively, efficiently and rapidly within stipulated period. On these guidelines restoration and management of vulnerabled soils is described here,

Vulnerability of Soils

Soil vulnerability, Soil degradation, soil vulnerability index

Water and wind erosion, depletion of soil organic matter, loss of plant nutrients, salinity, alkalinity, acidity, pollution and contamination, compaction, sealing, crusting, water-logging, aridity, lowering of water table, over grazing, deforestation, landslide, loss and change in soil biodiversity, Abandoned mines etc.

Soil vulnerability, Soil Degradation, Soil Vulnerability Index

The terms vulnerable and vulnerability are now bites of every one and used for everything. Vulnerable means to the possibility of attack or harm by any mean. Human beings are vulnerable to Covid-19, computers are vulnerable to virus, softwares are vulnerable to hackers and attackers to control system, environment is vulnerable to pollution. Vulnerabilities refer to the lack of ability to resist the effects of the aggressive environment. Soils are vulnerable to numerous threats like water and wind erosion, depletion of soil organic matter, loss of plant nutrients, salinity, alkalinity, acidity, pollution and contamination, compaction, sealing, crusting, water-logging, aridity, lowering of water table, over grazing, deforestation, landslide, loss and change in soil biodiversity etc. However, this book will describe some of the most pertinent vulnerabilities for soils.

Physical Properties of Soil

Physical properties of soil have many important roles in the crop production. The basic requirements for germination, seedling emergence and root development are adequate moisture and aeration, optimum temperature and absence of mechanical hindrance. After germination the further development of plant is also governed by physical conditions of soil. Soil texture, soil structure, soil density, soil consistence, soil water, soil air, soil temperature and soil colour are main physical properties of soils also affecting mechanical behaviour of soils. These are described here.

1. Soil Texture

The weathering divides larger particles of rocks and minerals in to the smaller ones. This process goes continuously. Thus, particles of different sizes ranging from large fragments of rocks to the very fine clay minerals are found in soil. However, for texture particles less than 2mm diameter is considered. The relative amount of these particles indicates the soil type also. Such as sandy soils contain more amounts of coarse particles i.e., sand and clayey soils are rich in fine particles. The rock and mineral particles having diameter less than 2.0 mm and come between specifies size are called as soil separates. International society of soil science (ISSS) and United States Department of Agriculture (USDA) systems are Generally, followed to classify the soil separates. This classification is given in table 3.1.

Genesis of Soil

World’s geography is very widely diversified in relief showing various features like mountains and hills covered with snow and trees, glaciers, higher altitudes to plain to lowest valleys, forests to barren lands, fertile fields to waste lands, plateaus, deltas, swamps, lowlands, deserts etc. Temperature varies from arctic cold to scorching hot of equator, Rainfall from aridity to per humidity. All these situations and conditions under different sets of combinations generate and develop numerous types of soil from a single type of parent material. Therefore, many types of soils may develop at a smaller area.

Physical, chemical and biological weathering processes disintegrate and decompose various rocks and minerals to make asymmetrical soil parent material. This parent material is converted in to the soil profile by soil forming processes in the presence of soil forming factors. Soil genesis is defined as mode of formation of the soil from the parent material due to the action of soil forming factors and processes. Parent material, Factors of soil formation and Processes of soil formation, are three main part of soil genesis. These are described here:

1. Parent Material,

2. Classification of parent material,

3. Factors of soil formation,

4. Processes of soil formation,

5. Types of soil forming processes.

This chapter presents a birds’ eye view of the soil to develop the interest among the readers to know more about the fundamental concepts of soil.

Soil is a major determinant of terrestrial ecosystems and helps in the distribution of land flora and fauna. Soils are sources, transformers and stores of plant nutrients. Soils are the recycling places of plant and animal residues and wastes. Soils are also the screen and filter of pollutants in many ways, forms and degrees. Soils are the main link and recharger of hydrological cycle. Soils influence radiant heat exchange, temperature change and land surface reflection characteristics. Soils are important sources and sinks of biogeochemical cycles of carbon dioxide, methane, nitrogen oxides and sulphur dioxide. Soil is used in buildings, roads, brick kiln, naturopathy etc. Soils are good record of past climatic conditions and human activities, as they have some stable features originated from the interactions of climate, organisms, relief, parent material and time. Soil provides nutrients, water, air, heat and mechanical support to arable plants to produce the food, fodder, fibre, fuel and other plant products for human and animals. Mainly the soil is studied as a natural body and as a medium for plant growth.