eChapters

Defining Wellbeing
The notion of wellbeing is not new, it is much more difficult to come up with a consensus definition since the phrase is frequently ill-defined and under-theorized (Camfield, Streuli & Woodhead, 2009). The problem of definition inconsistency is exacerbated by the fact that the phrases “wellbeing” and “happiness,” “flourishing,” “enjoying a good life,” and “life satisfaction” are frequently used synonymously, although having quite different connotations.
Defining wellbeing is tough because it's talked about in many different ways across local and global media, literature, and daily conversations. So many voices, so many angles. But that makes the journey of understanding it all the more fascinating! At first, there were two distinct schools of thinking on wellbeing: hedonic and eudemonic. From a hedonic perspective, happiness is defined as the sum of all happy experiences.
Philosophers like DeSade, Bentham and Hobbes defined wellness as the “pursuit of sensations and pleasure” Hobbes as “a pursuit of human appetites,” and Husain (2008) as “the good society is built through maximizing pleasure and self-interest.” Being loyal to one’s inner self and having a eudaimonic viewpoint on wellbeing are synonymous with the concept of eudaimonia. Maslow (1970) developed a notion of self that builds upon the eudaimonic idea of wellbeing. The conditions that exist in life and the ways in which a person or community makes use of those situations directly affect the quality of life that an individual or community experiences. Wellbeing has become “something everyone seemingly aims for and arguably has a right to,” according to McCallum and Price (2016).

Future Scope of the research
1. Inclusion of more number of relevant variables to generate and delineate complex interactions in the ecosystem functioning with a focus on agriculture, livestock, and forest.
2. The future research merits application of data analytics for visualization, prediction, and prescription of CA beyond time and geography
3. A robust Management Information System (MIS) needs to be the possibility of related to CA and allied natural resource management can help better and effective research interpretation and policy formulation as well,
4. Application of artificial intelligence can go immensely important in monitoring, auditing, and analyzing ecological services.
Recommendations from the study/ Area of Intervention
1. Rationalization of chemical fertilizer and pesticides in a gradual manner and for which there will an environmental policy in place,
2. A data bank needs to be created on agricultural pollution and necessary recommendation from the environment and pollution department need to be made,
3. Fragmentation has come out as one of the barrier towards the socialization of Conservation Agriculture since small farms are energy and input prodigal, so we have to go for community based farming or farm enterprise creation in state of isolated and individual endeavours,
4. Through panchayat and rural development sector policies need to be promulgated,
5. Gender issues are coming up very strong and conspicuous in Conservation Agriculture, the more is the women participation in CA, the better has been the success, hence, gender mobilization can be a program and policy of the government in making CA sustainable,

7.1. Summary
The planet rise at this moment cannot endure and conjure up any further stress and distress created by un-mindful modernization of agriculture. This situation has gone further complex with the unabated rate of urbanization. The natural resources which looked plenty some 50 years back, now is coming up something scant and degraded. We have to protect this planet; hence, we have to protect our agriculture by placing ecological resilience with its perfect balance and dynamics. In doing so, we need to manage and recycle energy, water, and biodiversity in such a way that the operating agro-ecosystem can perform for another centuries. This is a herculean task, it will only be possible when farmers and other citizens are participating elegantly and equally into the process, because farmers are not producing food for their own, rather they are feeding the entire civilization. Every year 15-20 tonnes of top soils are being eroded, the highest anytime; the sea level is rising at the rate 5-10 mm again it has become highest over the last decades and the prediction for rate of changes in rainfall and temperature contributing to global warming has been accelerate like anything. In addition to this, we need to feed 950 crores of population by 2050, while lands are getting fragmented, resources are fragile, and water is getting increasingly contaminated. Thus, CA is the only option to create a perfect balance between productivity with increase of ecological resilience, even within the cropping system by introducing crop diversification with leguminous crops and this is specially so when the biodiversity is also getting eroded. Water harvesting is the need of the hour as we can make our farm more energy parsimonious, we have direct whatever crop residues are produced in the soil echelon and making this concept a revolution into a reality we have to go in a massive way with bring awareness, creating policies, and mobilizing community to make our agriculture ever- green and ever- resilient.
On this context the present research has been conducted with the following objectives:

First Part: Multivariate Statistical Analysis
6.1. Results
The chapter deals with the result and discussion of the study using multivariate statistical analysis and participatory Rural Appraisal (PRA) techniques with the purpose to provide sufficient information so as to arrive at valid conclusion. Tables and models are commonly used in this chapter to support and supplement the textual materials. Discussion helps to interpret the results of the study in proper perspective and to relate them with other relevant studies.
Axiomatic statement on the variable interactions and behaviour selected for the study
Research setting in the present study presents a dynamic social-ecology which is evolving along and across the undulation of social process. Both the structural and functional dimensions and behaviour are in constant interaction and response with the subject respondents in terms of innumerable variables. For the present research only some selected characters have been selected for empirical titration. There is no wonder these variables can be catalogued in terms of dependent or independent variables rather should not be distributed in a binary mode. Rather these variables are with seamless transformations like the algorithm of quantum physics. That is how whenever a set of x variables are supposed to behave with a contributor characters the same can be responsive with a recipient behaviour, e.g. in stepwise regression, set of ‘x variables’ are not considered as the only source of causal variables along with the couple of ‘y variables’ which are promoting rest other y variables have also been considered as causal variables. Hence, in case of y1, the rest of the y variables have to be treated like: y2 = y2' ; y3' = y3; y4 = y4' and so on.

The deliberation on the methodology has been made to understand the concept, methods, and techniques which were utilized to design the study, collection of information, analysis of the data and interpretation of the findings for revelation of truths and formulation of theories. This chapter deals with the method and a procedure used in the study and consists of eight main parts-
• Locale of research
• Pilot study
• Sampling Design and Framework
• Empirical measurement of the variables
• Item analysis and experts rating for devising scoring technique on dependent variables
• Preparation of interview Schedule
• Pre testing of Interview Schedule
• Techniques of Data collection
• Statistical Tools used for Analysis of Data
5.1. Locale of Research
The present research has been carried out at Kasthodanga, Mollabalia, Madhpur, Baksha, and Mitrapur villages of Kasthodanga gram panchayat in Haringhata block; Rautari, Ghetu Gachhi, Maniktala para, Tentul Baria, Maheswarpur from gram panchayat in Chakdaha block of Nadia district; Boinchigram, Goara, Chau bera, Uttarkhanda, Champahati villages of Bantika- Boinchi gram panchayat in Pandua Block; Dhopapara, Beleswar, Ichhapura, Tiornai, Baksagari from Dhopapara gram panchayat in Balagarh block of Hooghly district from the Alluvial zone of West Bengal. From the Terai zone of West Bengal, Elejanerkuthi, Kalabarighat, Hourgari, Ghughumari, Gokuler Kuthi, Hirar kuthi from Coochbehar- 1 block; Pundibari, Kalarayerkuthi, Sukhdhanerkuthi, Khagribari, Singimari Paschimpar, Basdaha Natibari, villages of Coochbehar- 2 block; Mirer Kuthi, Kismat Dasagram, Bara Shakdal, Kochabari, Bamanhat-ii, Durganagar, villages of Dinhata 2 block

4. Research Setting
Research setting presents the set of an ecosystem, here social-ecological systems, where the variables and characters are created, evolved, characterized and interact with others. Research setting is not a stale or lentic ecosystem rather it is agile, evolving and dynamic, so in this present work, we have perceived research setting as the performing social-ecology which sustains and keeps constantly characterizing the behaviour and dynamics of the variables under study, e.g. a settlement in close proximity to natural water body is expected to have interaction with ethiophonal diversity and performing economy therewith similarly, another set of respondents with the same set of variables but living in a forest ecosystem. The interaction and exposition of the variables will follow a different expression and pathway. So, while we will go for modelling, with the same set of variables but in different ecological set up, it is expected that the nature of interaction and expression will follow the unique characters of the concerned ecosystem.
4.1. Area of Study
The area of investigation of this study is situated in the state of West Bengal located in the eastern part of India. The state of West Bengal in eastern India has unique social and ecological backgrounds which influence the living standard and behavioural patterns of the people in many ways. The present research design has accommodated two agro- ecological set ups in West Bengal, India, and these are New Alluvial and Terai zone.

3. Contemporary Crisis in Global Agriculture
Over the past century, bunch of initiatives have been taken and achieved worldwide in expediting human welfare. Societies have also changed to great extent as a result of quantum leaps in technology, rapid globalization, and innovations in agricultural production systems. Perhaps the world ‘free of fear and want’ envisioned at the foundation programme of the United Nations is still a far cry.
Similarly, much work left to be fulfilled the vision of the Food and Agriculture Organization of the United Nations (FAO) and to make ‘a world free of hunger and malnutrition and one in which food and agriculture contribute to improving the living standards of all, especially the poorest, in an economically, socially, and environmentally sustainable manner’.
Amidst great plenty, millions of people still face pervasive poverty, inequalities, joblessness, natural resource depletion, environmental degradation, displacement, migration, disease, and deprivation. Majority of humanity’s progress has reached at a significant cost to the environment. The impacts of climate change are already being felt, and if left unabated; definitely will intensify to a considerable extent in the years coming. Besides, population dynamics will radically change demographics over the decades ahead. Growth in the world’s population is projected to be concentrated in Africa and South Asia and in the biggest cities.
Then agricultural production has to maintain pace with those of rising population for atleast a sustainable world. Although, agricultural production more than tripled between the years of 1960 and 2015, where Green Revolution owes to robust crop production and a significant increment in the use of land, water and other natural resources for agricultural purposes. This period witnessed a remarkable progress in both of industrialization and globalization of food and agriculture. At the same time changes in the length of food supply chains took place as the physical distance from farm to plate has increased dramatically; the consumption pattern of processed, packaged, and prepared foods has changed simultaneously in everywhere though the most in rural communities.

This chapter reviews the research work done in the fields related to the objectives of the study. In any scientific investigation or research a comprehensive review of relevant literature is very essential. Its main function apart from determining the work done before concerning the problem area i.e. area of investigation, it provides an insight into the methods and procedures and create a basis for interpretation of findings. As direct references on all the item are not in abundance, certain specific references along with some indirect references have been incorporated this chapter for the purpose of meaningful use.
2.1. Ecosystem Services and Conservation Agriculture
Acharya, S. K. and Chatterjee, R. (2019) found that conservation agriculture may help in re-building agro-ecology by maintaining carbon sequestration, maintaining soil health, checking soil erosion and ground water depletion, energy balance, mitigating climate change related problems through maintaining ecosystem services.
Ayyam, V., Palanivel, S., and Chandrakasan, S. (2019) stated that CA embraces higher rates of carbon sequestration, organic matter accumulation, soil erosion reduction, and its associated improvement in soil biological properties. Additionally, there is reduction in greenhouse gas emission as a result of CA. Adoption of CA-based farming practices particularly in areas facing notable land degradation and depleting natural resources delineates a win-win scenario due to improved crop yield and trends of increasing soil fertility and scope for climate change adaptation to recuperate degraded soils and improve ecosystem services.

The magnitude and trajectory of changes in ecosystem services and functioning have been as conspicuous as has never been until before 1980’s in this subcontinent. Both the services and resilience of agro-ecosystem, the pivotal for agricultural production and security have been disrupted in the name of modernization of agriculture as well as commercialization.
The impact of green revolution in India, that look place during 1960’s and 1970’s have started eroding very fast and as the consequence of this green revolution, the ground water depletion has gone to the worst, it is contaminated either. 40 % of ground water in Punjab has been moderately or severely contaminated leaving agriculture a coercive proposition both from economic and ecological perspective. 10-15 tonnes of top soil are being eroded per hectare per year in its wrong welcoming to farm mechanization process. Most of the highly yielding varieties which did the ‘magic revolution’ now has been fatigued or segregated either. The social-ecological impacts on agriculture perhaps have been both disruptive and deleterious. Due to unabated fragmentation of holding which again is tiny in size, has initiated another problem of resource and energy wastage, bad enough to add to an ecological disruptions.
With a non-denial to the gleaming success of green revolution, which ensured us with much awaited food security and self-reliance, has its intrinsic weakness and coercion as well.

1. Introduction
Omega-3 fatty acids are a vital group of polyunsaturated fatty acids (PUFAs) recognized for their complex chemical structure, which is characterized by multiple double bonds within their hydrocarbon chains. This unique arrangement not only influences their physical and biochemical properties but also underpins their essential roles in various biological processes across a wide range of organisms. Omega-3 fatty acids are categorized into three primary types: alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). While ALA is predominantly found in plant sources, such as flaxseeds, chia seeds, and walnuts, EPA and DHA are primarily sourced from marine organisms, particularly fish and algae.
1.1 Importance of Omega-3 Fatty Acids
1.1.1 Nutritional Significance in Aquatic Organisms
In fish nutrition, omega-3 fatty acids are indispensable for promoting optimal growth, development, and overall health. These essential nutrients contribute to a multitude of physiological processes, including:
1. Cellular Structure and Function: Omega-3 fatty acids are integral components of cell membranes, influencing their fluidity and permeability. This is crucial for maintaining cellular integrity and facilitating the transport of nutrients and signaling molecules across membranes.

1. Introduction
Aquaculture is one of the most rapidly expanding sectors in food production, making significant contributions to global food security and the economy. As natural fisheries resources are depleted, aquaculture has become an essential source of protein and employment for millions worldwide. With an increasing demand for seafood, the intensification of aquaculture systems has become necessary. This intensification, characterized by high stocking densities, increased fish production, and automation, has introduced a range of challenges that negatively impact the health and well-being of farmed fish and other aquatic species.
1.1 Stress in Aquaculture Systems
Stress is an inevitable part of aquaculture, particularly in intensive farming systems where fish are exposed to multiple environmental, biological, and anthropogenic stressors. Stress refers to a physiological condition where the normal homeostasis of an organism is disrupted due to external stimuli. In aquaculture, stress can arise from various factors, including changes in water quality parameters (such as dissolved oxygen, temperature, and pH), overcrowding, transportation, handling, and exposure to pathogens. The physiological response to stress can lead to a cascade of negative outcomes, including suppressed immunity, impaired growth, decreased reproductive success, and increased susceptibility to disease. If not adequately managed, stress can cause significant economic losses, affecting the sustainability and profitability of aquaculture operations.

1. Introduction
Aquaculture has rapidly emerged as a crucial industry to meet the growing global demand for seafood, contributing significantly to food security and economic development. However, as aquaculture operations expand and intensify, fish health management has become increasingly challenging. The close confinement of fish in high-density farming systems creates ideal conditions for the spread of infectious diseases. Stressors such as overcrowding, fluctuating water quality, and improper nutrition further exacerbate the susceptibility of fish to pathogens. As a result, disease outbreaks in aquaculture are more frequent and can lead to severe economic losses due to reduced productivity, increased mortality, and the cost of treatments. In the past, antibiotics and other pharmaceutical treatments were widely used to manage fish diseases. While these methods have been effective in controlling infections, they come with several significant drawbacks:
• Antibiotic resistance: Overuse of antibiotics has contributed to the rise of antibiotic-resistant bacteria, a major public health concern that can affect not only aquatic organisms but also humans through the food chain.
• Residues in fish products: Antibiotics and other chemicals may leave harmful residues in fish, posing potential health risks to consumers and limiting the export potential of farmed fish products to markets with stringent regulations.
• Environmental contamination: The use of chemicals in aquaculture can lead to the contamination of surrounding water bodies, affecting wild fish populations and the broader ecosystem.
Due to these limitations, there is a growing demand

1. Introduction
Aquaculture has emerged as one of the fastest-growing food production sectors worldwide, a trend driven by several factors, including the rising global demand for seafood, the depletion of wild fish stocks, and the search for sustainable protein sources. As the human population continues to grow and dietary preferences shift towards healthier, protein-rich food options, aquaculture plays a pivotal role in addressing food security. However, the expansion of aquaculture also brings forth significant challenges, particularly in the efficient use of resources, including feed. One of the primary challenges for the aquaculture industry is ensuring that fish and other aquatic organisms receive optimal nutrition through formulated feeds. Aquafeeds are typically designed to provide a balanced mix of proteins, lipids, carbohydrates, vitamins, and minerals necessary for the growth, health, and reproduction of farmed species. However, not all nutrients in these feeds are equally digestible or absorbable by the animals. The efficiency with which nutrients are utilized depends largely on their bioavailability—a term that refers to the proportion of ingested nutrients that are available for absorption and utilization by the body.
1.1 Defining Nutrient Bioavailability in Aquafeeds
In aquaculture nutrition, nutrient bioavailability is a crucial determinant of overall feed efficiency. It is defined as the fraction of a nutrient that, after ingestion, becomes available for utilization in physiological processes such as growth, tissue repair, metabolism, and reproduction. In practice, this means that bioavailable nutrients must first be digested in the gastrointestinal tract, absorbed through the intestinal walls, transported to various tissues, and

1. Introduction
The global demand for seafood has surged in recent decades, driven by population growth, rising incomes, and an increasing awareness of the health benefits associated with seafood consumption. In response, the aquaculture industry has expanded rapidly, making it one of the fastest-growing food production sectors in the world. As aquaculture continues to scale up, the need for sustainable and nutrient-rich feed ingredients has become a central concern. Traditional feed ingredients, such as fishmeal and soy, have significant environmental and ethical challenges. Fishmeal, derived from wild-caught fish, contributes to the depletion of marine resources, while soy cultivation is associated with deforestation and high water usage.
In this context, algal biomass has emerged as a promising, sustainable alternative to traditional aquafeed ingredients. Often referred to as a “superfood,” algae, which include both microalgae and macroalgae (seaweeds), offer a rich source of essential nutrients that support the growth, health, and productivity of farmed aquatic species. Algal biomass is increasingly recognized for its unique ability to provide a wide range of proteins, essential fatty acids (such as omega-3 and omega-6), vitamins, minerals, and bioactive compounds that are critical to the optimal functioning of fish and other aquatic organisms.

1. Introduction
Aquaculture, the farming of fish and other aquatic organisms, has experienced exponential growth over the last few decades, becoming one of the fastest-growing food production sectors globally. This expansion is driven by the rising global demand for seafood, fueled by population growth, increased per capita consumption, and the recognition of fish as a healthy and nutrient-rich food source. According to the Food and Agriculture Organization (FAO), aquaculture now supplies more than half of the world’s fish for human consumption, a significant leap from the 1980s when it contributed only a fraction of global seafood production. However, this rapid growth poses challenges, particularly with respect to sustainable feed production.
One of the primary concerns in aquaculture is the reliance on fishmeal, a high-protein feed ingredient traditionally sourced from small, wild-caught fish species such as anchovies, sardines, and menhaden. Fishmeal is rich in essential nutrients, particularly amino acids, omega-3 fatty acids, and micronutrients, making it an ideal component for aquafeeds. However, its dependence on wild fish stocks has raised sustainability concerns, as the continuous harvesting of these species can lead to overfishing, biodiversity loss, and ecosystem degradation. Moreover, the rising demand for fishmeal in aquafeeds, coupled with finite fishery resources, has driven up its price, making it less economically viable for aquaculture operations, especially for small-scale farmers.

1. Introduction
Aquaculture is a rapidly expanding industry, playing a crucial role in addressing the global demand for high-quality protein sources as wild fish stocks face depletion. With aquaculture production on the rise, ensuring the health and productivity of farmed fish has become increasingly important. The health of the fish gut is central to achieving these objectives, as the gut is responsible not only for nutrient digestion and absorption but also for maintaining a strong immune defense. A well-functioning gut leads to better growth performance, reduced disease susceptibility, and improved overall fish welfare.
However, maintaining optimal gut health in aquaculture systems presents challenges. The intensive nature of fish farming can lead to stressors that compromise the gut environment, including changes in water quality, fluctuating diet compositions, and exposure to pathogens. Gut health issues often manifest in poor feed conversion ratios, slower growth, and higher mortality rates, all of which negatively impact aquaculture productivity and sustainability. Therefore, there is a growing focus on finding innovative and natural solutions to improve the gut health of farmed fish.
In recent years, the use of probiotics and prebiotics in fish nutrition has gained significant attention as an effective and eco-friendly strategy to modulate gut microbiota and enhance fish health. These functional feed additives are considered a natural alternative to antibiotics and other pharmaceuticals, which have historically been used to manage diseases and promote growth in aquaculture but come with risks of antibiotic resistance and environmental contamination.

1. Introduction
Nutritional genomics, also known as nutrigenomics, is an emerging field that seeks to understand how individual genetic variations influence responses to specific nutrients and how diet, in turn, affects gene expression and overall health. By studying the complex interactions between nutrients and the human genome, nutritional genomics aims to develop personalized nutrition strategies that optimize health, prevent disease, and improve dietary outcomes for individuals based on their unique genetic makeup.
In the past, nutrition science largely followed a “one-size-fits-all” approach, with general dietary recommendations applied to broad populations. However, advances in genomics have shown that people respond differently to the same foods based on their genetic profile. Factors such as nutrient metabolism, absorption rates, and predispositions to certain diseases can vary significantly among individuals. These discoveries have led to a paradigm shift toward personalized nutrition, where diet plans are tailored to an individual’s genetic predispositions, improving the effectiveness of dietary interventions and reducing disease risks.
Nutritional genomics spans several sub-disciplines, including nutrigenetics (the study of how genetic variations affect the body’s response to nutrients) and nutrigenomics (how nutrients influence gene expression). These two aspects work together to help researchers understand the dual relationship between diet and genetics, contributing to the development of personalized diets that account for metabolic and physiological differences.

1. Introduction
Functional feed additives are specialized, non-nutritive substances added to animal feed with the primary aim of enhancing health, growth, and performance beyond the basic nutritional requirements. Unlike traditional feed ingredients that primarily provide essential nutrients, functional additives are intended to optimize physiological functions and overall well-being in animals. In the context of aquaculture, these additives are particularly crucial for improving the efficacy of fish diets, as they can significantly influence various health and performance parameters.
Functional feed additives can be derived from a diverse array of sources, including:
• Microorganisms: Probiotics and prebiotics that support gut health and improve digestion.
• Plants: Phytochemicals, such as flavonoids and alkaloids, which have antioxidant, anti-inflammatory, and immunostimulatory properties.
• Natural Compounds: Various extracts and essential oils known for their therapeutic effects on fish health.
By integrating these additives into aquafeeds, aquaculture practitioners aim to promote fish welfare, enhance production efficiency, and ultimately contribute to sustainable fish farming practices.

Introduction
The rapid expansion of global aquaculture, driven by the increasing demand for high-quality, protein-rich seafood, has necessitated significant advancements in feed production. Historically, fishmeal and fish oil—derived from wild-caught fish—have been the cornerstone ingredients in aquafeeds, providing essential proteins and lipids for the optimal growth, health, and productivity of farmed species. However, the over-reliance on these finite marine resources has raised a host of environmental, economic, and ethical challenges. The depletion of wild fish stocks due to overfishing, habitat degradation, and climate change threatens the sustainability of global fisheries. Moreover, the volatility in the cost and availability of fishmeal and fish oil has placed increasing economic strain on the aquaculture industry, which is projected to grow substantially in the coming decades. These concerns have spurred the search for alternative, sustainable feed ingredients that can reduce dependence on wild-caught fish while maintaining or even improving the nutritional value and health outcomes for farmed fish. This chapter explores the ongoing evolution of sustainable feed ingredients and their crucial role in shaping the future of aquaculture. It highlights innovative approaches, such as plant-based proteins, insect meals, and microbial sources of omega-3 fatty acids, which offer promising solutions to enhance the sustainability of aquafeeds. By addressing both the environmental impact and economic viability of aquaculture feed production, these alternatives represent a pivotal shift towards a more responsible, resilient, and efficient aquaculture industry poised to meet the growing global demand for seafood.

Introduction
Fish nutrition is a critical determinant of growth, reproduction, and overall health in aquaculture systems. A thorough understanding of the nutritional physiology of fish lays the groundwork for designing innovative feeding strategies that improve fish production, health, and sustainability. Unlike terrestrial animals, fish have unique physiological traits that influence their dietary needs and how they process nutrients, requiring specialized nutritional approaches. This chapter provides a detailed exploration of these physiological features and their implications for the development of cutting-edge nutritional innovations in aquaculture.
1. Basics of Fish Anatomy and Physiology Related to Nutrition
Fish anatomy and physiology particularly in the context of nutrition present unique characteristics that differentiate them from terrestrial animals. One of the most significant features of fish is their poikilothermic nature, meaning their body temperature fluctuates with the surrounding water. This directly impacts their metabolism, as colder waters slow down metabolic processes, reducing the need for energy, while warmer waters increase metabolic rates, driving higher energy demand. This temperature dependency is critical in understanding the feeding behavior and nutritional needs of different fish species. Unlike mammals or birds, which expend energy to maintain a constant internal body temperature, fish can allocate a greater proportion of their consumed nutrients toward growth, reproduction, and immune function.