This book summarizes the latest understanding of the impact of xenobiotics on the developmental and reproductive processes of aquatic animals, particularly nektonic forms, which comprise an important group of aquatic ecosystems.

Aquaculture is quickly becoming the largest contributor of fish protein for human consumption. As the aquaculture business expands, farmed fish will be exposed to more environmental toxins, necessitating the use of chemical therapeutic drugs for fish. This book brings together experts on the regulation of environmental toxins and food chemicals from around the world, as well as researchers looking into the metabolism and disposal of foreign chemicals (xenobiotics) in fish species. The impact of xenobiotics on reproductive and developmental biology of all living forms has become of prime importance at the current time. As the effect of these xenobiotics on aquatic animals is an emerging area for research and development, several groups across the world are working on these aspects, targeting different groups of fishes in both marine and freshwater ecosystems.

 This collective work highlights several key and updated recent aspects of different types of xenobiotics entering aquatic ecosystems, impacts of these agents on reproductive physiology, developmental biology, breeding biology, hormonal imbalance, aquatic ecology, and pollution on the aquatic ecosystem. The unique aggregation of different types of stressors to aquatic animals under a single volume will be a useful reference for readers, including scientists, teachers, students, researchers and policymakers and those involved in aquaculture and environment conservation..

Pesticide and Xenobiotic Metabolism in Aquatic Organisms 1 Introduction 2 Pesticides and Xenobiotics 2.1 Classification of Pesticides 2.2 Pesticide Categories 2.2.1 Chemical Structure of Pesticides 2.2.2 Organochlorine Pesticides (OCPs) Organophosphate Pesticides Carbamate Pesticides Pyrethroid Pesticides Pesticides in Water Resources Fate and Effects of Pesticides in Aquatic Ecosystems Direct Effects of Pesticides Indirect Effects of the Pesticide on the Aquatic Community 2.3 Pesticide Metabolism in Aquatic Animals 2.3.1 Paraquat 2.3.2 Copper Sulfate 2.3.3 Diquat 2.4 Bioconcentration of Pesticides 2.5 Bioaccumulation of Pesticides 3 Xenobiotics 3.1 Common Xenobiotic Compounds Based on Its Course of Action 3.1.1 Analgesics and Nonsteroidal Anti-inflammatory Drugs (NSAIDs) 3.1.2 Mode of Action 3.1.3 NSAIDs (Nonsteroidal Anti-inflammatory Drugs) 3.1.4 Blood Lipid Regulators 3.1.5 Beta-Blockers 3.1.6 Neuroactive Compounds (Antiepileptics and Antidepressants) 3.1.7 Mode of Action 3.1.8 Various Other Compounds 3.1.9 Effects of Xenobiotics on Ecosystem 3.1.10 Effects on Aquatic Ecosystem 4 Bioconcentration and Bioaccumulation of Xenobiotics 4.1 Biomagnification of Xenobiotics 4.2 Xenobiotic Compounds: Other Effects 4.3 Marine Life Affected by Xenobiotics 4.4 Food-Based Xenobiotic Uptake 4.5 Xenobiotic Metabolism in Aquatic Animals 4.5.1 Enzymes Involved in Phase I Metabolism 4.5.2 Enzymes Involved in Phase II Metabolism Toxicity of Xenobiotics in Aquatic Ecosystems 5 Conclusion References Endocrine-Disrupting Activity of Xenobiotics in Aquatic Animals 1 Introduction 2 Xenobiotics-Induced Toxic Manifestations 3 Stress 4 Effects of Xenoestrogens 5 Effect of Xenobiotics on Fish Reproduction 6 Effect of EDCs in Aquatic Mammals 7 Freshwater Mammals 8 Bisphenol A (BPA) 9 Toxic Effects of Bisphenol A on Goldfish Gonad Development and the Possible Pathway of BPA Disturbance in Female and Male Fi... 10 Effect of Endocrine-Disrupting Chemicals on Fish Gamete 10.1 Effects of EDC Exposure on Ovarian Physiology 10.2 Effect of EDCs on Morphology of the Ovary and Oocyte Growth, Maturation, and Fertility 10.3 EDC Effects on Molecular Markers Linked to Steroidogenesis, Ovarian Growth, and Maturation 10.4 Effects of EDC Exposure on Male Gonadal Physiology and Functionality 11 Spermatozoa Production, Morphology, Motility, and Velocity 12 Effects of EDCs on Steroidogenesis and Hormone Synthesis 12.1 Effects of EDCs on Sex Reversal 12.2 Effects of EDCs on Epigenetic Process References Water Contamination Through Xenobiotics and Their Toxic Effects on Aquatic Animals 1 Introduction 2 Transport Route of Xenobiotic Compounds 3 Classification of Xenobiotics 4 Classification of Xenobiotic Sources 4.1 Direct and Indirect Sources 4.2 Product and Processes as a Source 4.2.1 Deliberate and Accidental Causes 4.2.2 Moving and Stationary Sources 4.2.3 Regulated and Unregulated Sources 5 Sources 5.1 Personal Care Compounds 5.2 Flame Retardants 5.3 Pharmaceuticals 5.4 Steroid Hormones 5.5 Biocides 5.6 Polycyclic Aromatic Hydrocarbons (PAHs) 5.7 Corrosion Inhibitors 6 Physicochemical Nature of Xenobiotics 7 Water Contamination Through Xenobiotics 8 Impact of Xenobiotics on Aquatic Life 8.1 Microplastics 8.2 Mercury Accumulation 8.3 Oxidative Stress 8.4 Heavy Metals 8.5 Mercury 8.6 Lead 8.7 Cadmium 8.8 Pesticides 8.8.1 Classification of Insecticides 8.8.2 Herbicides 8.8.3 Fungicides 8.9 Dyes 9 Pesticides in the Aquatic Ecosystem 10 Conclusion and Future Perspectives References Cypermethrin-Induced Reproductive Toxicity in Zebrafish: Biochemical and Molecular Perspective 1 Introduction 2 Applications and Pathways of Cypermethrin in Aquatic Systems 3 Exposure Routes for Absorption of Cypermethrin 4 Toxicological Mechanisms of Cypermethrin 4.1 Induction of Oxidative Stress 4.2 Disturbances in Ion Channels 4.3 Induction of DNA Damage 5 Reproductive and Developmental Toxicity in Zebrafish 6 Impacts in Female Zebrafish 7 Impacts in Male Zebrafish 8 Impacts in Zebrafish Embryo 9 Conclusion References Impact of Pesticide Application on Aquatic Environments and Biodiversity 1 Introduction 2 Pesticides 2.1 Insecticides 2.1.1 Carbamate 2.1.2 Organophosphate 2.1.3 Pyrethroids 2.1.4 Organochlorine 2.2 Fungicides 2.3 Herbicides 2.3.1 Chlorophenoxy-Based Herbicides 2.3.2 Glyphosate 3 Sources of Pesticides into Aquatic Ecosystems 3.1 Point Sources 3.2 Nonpoint Sources 4 Pesticides in Aquatic Environments 5 Behavior and Fate of Pesticides in Aquatic Ecosystems 5.1 Release of Pesticides in the Water 5.2 Mobility 5.3 Persistence 5.4 Patterns of Application 5.5 Site Condition 6 The Impacts of Pesticides on Aquatic Ecosystems 7 Impact on Aquatic Flora 8 Impact on Aquatic Fauna 9 Routes of Exposure to Fish 10 Effect on the Hematological Parameters of Fish 11 Pesticides as Genotoxic Agents 12 Effect of Pesticides on the Reproductive System of Fish 13 Effect of Pesticides on Various Biochemical Processes in Fish 14 Impact on the Behavioral Changes of Fish 15 Effect of Pesticides on Animal Diversity References Impact of Microplastics on Reproductive and Physiological Aspects of Aquatic Inhabitants 1 Introduction 2 Occurrence of Microplastics in Aquatic Systems 3 Exposure Route of Microplastics in Aquatic Inhabitants 3.1 Effect of Microplastics on Reproductive Aspects 3.2 Effect of Microplastics on Various Physiological Aspects 4 Conclusion References The Impact of Xenobiotics in Development and Reproduction of Freshwater Fishes 1 Introduction 1.1 Types or Chemical Nature and the Applications of Xenobiotics 1.2 Impact on Different Freshwater Fish Species 1.2.1 Cypermethrin 1.2.2 Chlorpyrifos 1.2.3 Dichlorvos 1.2.4 Fipronil 1.2.5 Atrazine 1.2.6 Others 1.3 Impact in Cold Water Hill Stream Fishes 1.4 Impact on Fish Reproduction 1.5 Concluding Remarks References Contaminant Mixtures and Reproduction in Aquatic Organisms 1 Introduction 2 Ecotoxicology Approaches to Mixtures 3 Reproduction in Mixture Toxicology 3.1 Standardized Toxicology Tests That Assess Reproduction 3.2 Expanding Beyond Fecundity in Reproduction 4 Mechanisms of Reproduction and Mixture Toxicology 4.1 Hypothalamus-Pituitary-Gonad Axis in Fish 4.2 Fish Gonads 4.3 Mixture Studies Assessing Endpoints Beyond Fecundity 5 The Challenges the Field of Ecotoxicology from Contaminant Mixtures References Phytoestrogens as Endocrine-Disrupting Agents in Aquaculture 1 Introduction 2 Structure and Classification of Phytoestrogens 2.1 Flavonoids 2.1.1 Isoflavones Genistein Daidzein Glycitein Biochanin A and Formononetin 2.1.2 Coumestrol 2.2 Lignans 2.3 Stilbenes 3 Phytoestrogen on Reproduction Mechanism of Endocrine Disruption 3.1 Effect on Gonadotropins and Thyroid Homeostasis 3.2 Effect on Steroidogenesis 3.3 Effect on Vitellogenesis in Fish 3.4 Effect on Gonadal Development and Sex Reversal 4 Beneficial Effects of Phytoestrogens 5 Conclusion References A Proteomic Approach to Studying the Effects of Xenobiotics on Aquatic Living Organisms 1 Introduction 2 Proteomics 3 Evolution of Proteomic Research 4 Types of Proteomic 5 Biomarkers in Xenobiotics 6 Methods Used in the Identification of Xenobiotic Markers 6.1 Quantitative Proteomics 6.2 Techniques Used to Quantify Proteome 6.3 Gel-Based Quantification 6.3.1 Two-Dimensional Gel Electrophoresis (2-DE) 6.4 Gel-Free Quantification 6.4.1 Label-Free-Based Method 6.4.2 Label-Based Method 6.5 Mass Spectrometry (MS) 6.6 Mass Analyzer 7 Database Searching and Software 8 Proteomic Application in Fisheries 8.1 In Culture Species 8.2 Authentication and Food Safety in Aquaculture 8.3 Welfare in Aquaculture 8.4 Immunoproteomics 8.5 Nutriproteomics 8.6 Climate Change and Toxicology 9 Conclusion References Role of Cytochrome P450 in Xenobiotic Metabolism in Fishes (Review) 1 Introduction 2 Cytochrome P450 Metabolism 3 Effects of Environmental Pollutants on Cytochrome P450 (CYP1A) 4 Conclusion References Pharmacokinetic-Pharmacodynamic Modeling of Xenobiotics: Fate and Effect in Aquatic Animals 1 Introduction 2 Pharmacokinetics of Drugs in Aquatic Animals 2.1 Absorption of Drugs 2.1.1 Transportation of Drugs 2.1.2 Factors Affecting Absorption of Drugs 2.1.3 Route of Drug Administration in Fish 2.2 Distribution of Drugs 2.3 Metabolism of Drugs 2.4 Excretion of the Drug 2.4.1 Filtration Mechanism (Steps) 3 Pharmacodynamics of Drugs in Aquatic Animals 3.1 Drug Dosage References Occurrence of Xenoestrogen Alkylphenols (Octylphenols and Nonylphenol) and Its Impact on the Aquatic Ecosystem 1 Introduction 2 Distribution of Alkylphenols 3 Effect on the Aquatic Species 3.1 Male Reproductive System 4 Female Reproductive System 5 Effect on Growth of Microalgae 6 Effect on the Mollusk 7 Conclusion References Xenobiotics´ Effect on Fish Reproduction and Development 1 Introduction 2 Xenobiotics and Toxicity 3 Absorption of Xenobiotics in Fish 4 Biotransformation of Xenobiotics in Fish 5 Stress Signal Transduction by Xenobiotics in Fish 6 Xenobiotic Action on Steroid Hormones 7 Xenobiotic Interactions with Steroidogenesis 8 Vitellogenin as an Indicator of Estrogen Exposure 9 Vitellogenin Indicative of Reproductive Dysfunction 10 Energetic Adaptation 11 Non-vitellogenic Responses 12 Ecological Consequences 13 Types of Endocrine Disruptive Chemicals (EDCs) 14 Target of endocrine disrupting chemicals in Fish 14.1 Thyroid 14.2 Interrenal Gland 14.3 Gonads 14.4 Fish Reproduction 15 Conclusion References Scientometric Analysis of Ecotoxicological Investigations of Xenobiotics in Aquatic Animals 1 Introduction 1.1 What Are Xenobiotics? 1.2 Xenobiotics in Various Fields 1.3 World Scenario of Xenobiotics 1.4 Xenobiotics in Aquatic Environments 1.5 How It Affects the Aquatic Environment 2 Materials and Methods 3 Results and Discussion 3.1 Xenobiotics 3.2 Xenobiotics in Fish 3.3 Effect of Xenobiotics on Fish Physiology 4 Conclusion 5 Virtual Reality Application in Various Domains 6 Status of Fisheries Education in India 7 Possible Virtual Reality Application in Fisheries Education 8 Distance Learning/Virtual Classrooms 9 Virtual Field Visits 10 Virtual Fish and Fish Systems 11 Virtual Labs 12 Conclusion References Toxic Effects of Nanomaterials on Aquatic Animals and Their Future Prospective 1 Introduction 2 Aquatic Organisms and Penetration of Nanomaterials 2.1 Toxicological Effects of Nanomaterials on Aqueous and Terrestrial Ecosystems 2.1.1 Uptake of Nanomaterials in Aquatic Ecosystems 2.2 Toxicological Profiling of NMs in the Aquaculture Sector 3 Effects of NPs on Aquatic Animals 3.1 In Fish 4 Toxicity of Nanomaterials 5 Bio Modification and Migration Along Food Webs 6 Current Nanotechnology in Aquaculture 7 Conclusions References Microplastic Contamination in Aquatic Organisms: An Ecotoxicological Perspective 1 Introduction 2 Sources of Microplastics 2.1 Primary Microplastics 2.2 Secondary Microplastics 3 Microplastics in Aquatic Organisms 4 Eco-Toxicological Effects of Microplastics 5 Management of Microplastics 6 Conclusions References Effects of Xenobiotics and Their Degradation in Aquatic Life 1 Introduction 2 Epithelial Transport in Aquatic Organisms´ Digestive System 2.1 Transporters of Nutrients and Endogenous Substrates 3 Impact of Xenobiotics on Aquatic Life/Fauna 4 Impacts of Xenobiotics on the Ecosystem 5 Biodegradation of Xenobiotics 6 Degradation of Xenobiotics Through Bacteria 7 Degradation of Xenobiotics Through Fungi 8 Conclusion References Transcriptome Analysis of Aquatic Species Exposed to Endocrine Disruptors 1 Introduction 2 Different Endocrine Disruptor Compounds (EDCs) 2.1 Arsenic 2.2 Cadmium 2.3 Chromium 2.4 Lead 2.5 Mercury 3 The Workflow of Transcriptomics Through Illumina Sequencing 4 Bioinformatics Analysis 5 Transcriptomics of EDCs-Exposed Aquatic Life 6 Conclusion References Fundamentals of Genotoxicity and Antiparasitic Drugs Associated with Genotoxicity in Fish 1 Introduction 1.1 Genotoxicity and Underlying Mechanism 1.1.1 Direct Acting Agents 1.1.2 Indirect Acting Agents 1.1.3 Genotoxicity Assessment Techniques 1.1.4 Micronuclei Test (MNT) 1.1.5 Comet Assay 1.1.6 Chromosomal Aberrations 1.1.7 Sister Chromatid Exchange 1.1.8 Ames Test 2 Toxicity Associated with Antiparasitic Drugs 2.1 Genotoxicity Study in Fishes 2.2 Gene Expression Associated with Genotoxicity 3 Conclusion References Endocrine-Disrupting Compounds (EDCs) as Emerging Aquatic Contaminants: Emphasis on Reproduction and Development 1 Introduction 2 Endocrine-Disrupting Chemicals (EDCs) 3 Effects of EDC Exposure on Fish Reproduction and Development 4 Conclusion