Short answers, pulled from the story.
The Food and Agriculture Organization defines aquaculture as the farming of aquatic organisms including fish, molluscs, crustaceans, and aquatic plants. This practice requires some form of intervention in the rearing process such as regular stocking, feeding, and protection from predators.
The Gunditjmara people in south-western Victoria may have raised short-finned eels as early as about 4580 BCE. They developed about 10 hectares of volcanic floodplains near Lake Condah into a complex of channels and dams to capture and preserve eels for year-round consumption.
By 2022 global aquaculture operations had risen to produce 130.9 million tonnes of aquatic organisms. The value of this output reached USD 312.8 billion during that same year.
A farm with 200000 salmon discharges more fecal waste than a city of 60000 people directly into the surrounding aquatic environment untreated. This waste often contains antibiotics and pesticides leading to an accumulation of heavy metals like copper and zinc on the benthos near the farms.
Some 16 countries now use geothermal energy for aquaculture including China Israel and the United States. In California alone 15 fish farms produce tilapia bass and catfish using warm water from underground to generate 4.5 million kilograms of fish annually.