Water pollution is the contamination of water sources by substances which make the water unusable for drinking, cooking, cleaning, swimming, and other activities. Pollutants include chemicals, trash, bacteria, and parasites. All forms of pollution eventually make their way to water.

Fisheries science is the study of freshwater, marine and/or estuarine aquatic systems that involve humans. A fishery is any body of water with which humans interact, such as in the form of fishing or swimming. A body of water that does not involve human interaction in one form or another is not a fishery.

For the purpose of sustainable development of aquaculture and fisheries, biotechnology proves to be a very effective tool. The combination of genetic alteration and biotechnology to expand the production of aquatic species, embraces incredible potential to take care of demand as well as to ameliorate aquaculture. Researchers are exploring genes that might enhance the generation of natural fish growth factors and additionally, the natural defense compounds marine living beings utilize to battle microbial contaminations.

Fisheries ecology and management employs mechanisms that regulate fish populations, food webs, and community structure and dynamics. Pollution and global warming have been the predominant causes of unprecedentedly low fish stocks in recent years. Fish communities can be altered in a number of ways which affects predator and prey dynamics.

Developing and implementing policies that enable marine aquaculture and works to ensure that aquaculture complies with existing federal laws and regulations are a very essential step in the field of aquaculture. Such policies and regulations ensure environmental protection, water quality, food safety, increase efficiency, transparency, and predictability in making permit decisions and protection of public health.

Captive fishing, also known as wild fishing is exploitation of aquatic organisms without stocking the seed. This often exists in the sea, rivers, reservoirs, continental shelves, around coasts, etc. Fish yield decreases gradually in capture fisheries due to indiscriminate catching of fish including brooders and juveniles. Captive Fishing and their subsequent re-introduction of an endangered species is an essential and in some instances a quite successful method for conservation of such species.

Growing concern over the environmental impact of aquaculture, in any case, has incited an analysis for an administration structure that can ensure supportability – that is, a fiscally reasonable aquaculture industry in which the ecological harm is limited. Sustainable aquaculture is a dynamic idea and the supportability of an aquaculture framework will fluctuate with species, area, societal standards and the state of information and innovation.

One of the fastest developing food-producing sectors is Aquaculture, and as of now contributes about 40% of the world supply of fish and other aquatic organisms. The advantages of the development are no doubt genuine and unmistakable for both producing countries and for consumers in the form of lower prices. Ideally it is likely to be able to attach a monetary value to the ecological effects of aquaculture, and in a few occurrences this is conceivable where a quantifiable impact on creation can be distinguished.

The sub-discipline of biology concerned with the study of all life forms that inhabit oceans and freshwater of the earth is known as marine and aquatic biology.   Life forms possess morphological and anatomical adaptations that empower them to live and flourish in aquatic habitats. Scientific investigations inherent to this field often analyze the human impact on and interaction with aquatic systems and range from the molecular level of contaminants to the stresses on entire ecosystems.

A method of cultivating aquatic plants in water comprises of aquatic plant farming. Such plants are fundamental to a healthy aquatic ecosystem. They can act as a source of sustenance for fishes and also provide oxygen. Floating aquatic plants shut out sunlight from reaching the rest of the water column which in turn limits the growth of other aquatic plants and can also regulate the amount of oxygen so that the fish can breathe.

Aquatic physiology studies the morphology and function of the various parts of the organisms inhabiting the aquatic ecosystem. The effect of environmental stress conditions on the aquatic inhabitants can be studied with the help of structural and physiological information obtained from this field of study.

Aquaculture engineering aims to provide solutions to technical problems related with harvesting of aquatic vertebrates, invertebrates, and algae. Design and development of the field not only requires knowledge of mechanical, biological and environmental systems but also of material engineering and instrumentation. Solutions from wastewater treatment, fisheries, and traditional agriculture additionally aid in engineering techniques.

The effective and efficient utilization of the available resources pertaining to aquaculture is referred to as aquaculture resource management. It is required keeping in mind the end goal to decide the best maintainable yield of market-sized animals within a given time period. Such management is required to employ utilization of financial information and ecosystem services valuation philosophies alongside past researches.

Aquaponics is basically the blend of aquaculture and hydroponics in a symbiotic environment. The fish waste gives a natural sustenance source to the plants, and the plants actually filter the water for the fish. Ammonia from the fish waste is first converted into nitrites and then to nitrates by the nitrifying bacteria. Additionally, fish waste is converted into vermicompost that acts as a food for the plants.

Aquafarming is the cultivating of fish, crustaceans, molluscs, aquatic plants, algae, and other aquatic organisms. It includes developing freshwater and saltwater populaces under controlled conditions, and can appear differently in relation to commercial fishing, which is the reaping of wild fish. On aquafarms, high-volume frameworks control nourishment, light on indoor homesteads, and development incitement. The Food and Agriculture Organization of the United Nations reports that the aquaculture business is growing three times quicker than terrestrial animal horticulture, and aquafarms will without a doubt turn out to be significantly more common as our regular fisheries wind up noticeably depleted.

Seaward fish ranches are driving the charge with regards to cutting edge aquaculture innovation, procedure and outline. Advancements in research keep on leading to changes in aquaculture generation frameworks, bringing about expanded creation productivity, higher product quality for customers and a more sustainable industry.

The strategies and the procedure utilized for catching the fishes for various purposes are termed as fishing technology. The term may likewise be applied to techniques for capturing other aquatic animals such as molluscs and edible marine invertebrates. Some of the fishing techniques comprises of hand gathering, spearfishing, netting, angling and trapping. The successful utilization of fishing techniques relies upon knowledge about the fish and their behavior including migration, rummaging and natural surroundings.

Various materials, including nylon, polyester, polypropylene(PP), polyethylene(PE), polyamide(PA), plastic-coated welded wire, rubber, patented rope products, galvanized steel and copper are used for netting in aquaculture fish enclosures around the world. The material strength of net panels made with PA, PP and PE gets reduced when exposed to sunlight (UV), wind, rain, acid rain, etc. Materials being soft can also be damaged by crabs and fish with strong dentations resulting in fish escape from the cage. By inhibiting microbial growth, copper alloy aquaculture cages avoid biofouling costly net changes that are necessary with other materials.

Integrated multi-trophic aquaculture (IMTA) includes developing fed species with extractive species that use the inorganic and organic wastes from aquaculture for their development. It consolidates, in the fitting extents, not only the cultivation of fed aquaculture species with organic extractive aquaculture species but also inorganic extractive aquaculture species to make adjusted frameworks for ecological maintainability, monetary dependability, and social acceptability.

Mariculture alludes to the development of marine life forms in seawater, more often than not in protected coastal waters. The cultivation of marine fish is a case of mariculture, thus additionally is the cultivating of marine crustacean, e.g. shrimp, molluscs, e.g. oysters and kelp. Mariculture may comprise of raising the life forms on or in simulated walled in areas, for example, floating fenced areas for salmon and on racks for oysters. For the instance of enclosed salmon, they are fed by the operators and oysters on racks channel feed upon naturally accessible food.

Algaculture is the commercial harvesting of algae. It is a type of aquaculture. A major portion of the algae that are deliberately developed fall into the classification of microalgae, additionally alluded to as phytoplankton, microphysics, or planktonic green growth. Macroalgae, normally known as kelp, additionally have numerous uses, however because of their size and the particular environmental requirements in  which they have to develop, they don't lend themselves as promptly to development on an extensive scale as microalgae and are frequently harvested wild from the sea.

Another noted aquaculture practice is the oyster cultivation where oysters are reared mainly for human consumption. Oyster farming began as early as 1^st century BC on the Italian peninsula by the ancient Romans and later developed in Britain too for the purpose of export to Rome. Aquacultured oysters were the main source of oysters for the French oyster industry since the late 18^th century. Oysters normally develop in estuarine bodies of salty water. They generally reach market size within 18 months to 2 years

Shrimp farming is the practice of harvesting shrimp or prawns for human utilization. This can be carried out in marine or freshwater systems. It is an aquaculture business that started in the 1970s, and production developed steeply, especially to coordinate the market requests of the United States, Japan, and Western Europe. Shrimp cultivating has made considerable progress and has changed into a worldwide industry, from the little scale cultivates in Asia and Thailand. There are just a couple of types of shrimp that are cultivated internationally. A standout amongst the most well-known species is the Macrobrachium rosenbergii, the Giant Malaysian Prawn, which is a freshwater prawn, local of South Asia.

Fish stocking is the act of rearing fish in hatcheries and discharging them into a waterway, lake, or the sea to make new or supplement existing populaces of threatened or endangered fishes in a waterway shut to angling. Fish stocking can give many advantages, for example, making new fisheries or expanding existing ones and is perceived for its significance to the group regarding quality business, recreational, or tribal angling, conservation purposes, employment and ensuing monetary advantages that have developed in light of the action over numerous years. Protection and conservation of our unique biodiversity should be ensured while fish stocking.

A fish hatchery is an area for artificial breeding, hatching and raising through the early life phases of animals, finfish and shellfish in particular. A few fish species that are usually brought up in hatcheries consists of Pacific oysters, shrimp, Indian prawns, salmon, tilapia and scallops. Hatcheries deliver larval and juvenile fish (and shellfish and crustaceans) principally to aid the aquaculture business where they are exchanged to on-growing systems i.e. fish farms to achieve reap estimate.

Like humans and other organisms, fish suffer from parasitic infestation and diseases. The defensive mechanisms can be specific and non-specific. Non-specific mechanisms consist of skin and scales, and additionally the mucus layer secreted by the epidermis that traps microorganisms and restrains their growth. On the off chance that pathogens break these defenses, fish can create inflammatory responses that enhance the flow of blood to infected territories and deliver WBCs that attempt to kill the pathogens. Specific defenses are specific reactions to specific pathogens perceived by the fish's body that are adaptive immune reactions.

At the point when fishes are kept in aquaculture, it must be ensured that the fish get the supplements they require for development and proper health. Fish meal and fish oil have been the customary beginning stages for good fish feed, since they contain the supplements that fish require. It has turned out to be certain that plant proteins can supplement fish meal, since crude materials from the plant kingdom contain adequate measures of the critical amino acids, which are the building squares of proteins. Fish meal ought to contain significant measures of iodine, selenium and vitamin A.

Pisciculture or fish farming includes raising fish in tanks or walled in areas, mostly for sustenance. It is the most significant form of aquaculture, while different techniques may fall under mariculture. Around the world, the most critical fish species utilized as a part of fish farming are carp, tilapia, salmon, and catfish. Fish farms can appear as submerged mesh cages or as solid enclosures in areas ashore. Today, an enormous portion of the fish consumed globally is raised in these artificial environments.