Fish farming is a form of aquaculture. It involves raising fish commercially in ponds for human consumption. There are different fish farming that utilize different aquiculture methods.
This method uses cages that are placed in lakes, oceans, and ponds that contain fish. This method is also commonly known as off-shore cultivation. Fish are normally kept in cages where they are artificially fed and harvested. The fish farming cage method has made numerous technological advances over the years, especially with reducing diseases and environmental concerns. However, the number one concern of the cage method is fish escaping and being loose among the wild fish population.
Irrigation Ditch/Pond Systems
This basic requirement for this method is to have a ditch or a pond that holds water. This is a unique system because at a small level, fish are artificially fed and the waste produced from the fish is then used to fertilize farmers’ fields. On a larger scale, mostly in ponds, the pond is self-sustaining as it grows plants and algae for fish food.
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Composite Fish Culture
This is a type of fish farming that allows both local fish species and imported fish species to coexist in the same pond. The number of species depends, but it is sometimes upwards of six fish species in a single pond. The fish species are always carefully chosen to ensure that species can coexist and reduce competition for food.
Integrated Recycling System
This is considered the largest scale method of “pure” fish farming. This approach uses large plastic tanks that are placed inside a greenhouse. There are hydroponic beds that are placed near the plastic tanks. The water in the plastic tanks is circulated to the hydroponic beds, where the fish feed waste goes to provide nutrients to the plant crops that are grown in the hydroponic beds. The majority of types of plants that are grown in the hydroponic beds are herbs such as parsley and basil.
Classic Fry Farming
This method is also known as “flow through system”. This is when sport fish species are raised from eggs and are put in streams and released.
Different Fish Species Raised on Fish Farms
There are a number of different fish species that are raised on fish farms, the most common fish spices raised are salmon, carp, tilapia, catfish and cod.
Catfish are easy to farm in warmer climates. Catfish are predominantly farmed in fresh water ponds and fed mostly soybeans, corn and rice. Catfish are often considered one of the more sustainable fish specifies for fish farming purposes. Cultivating catfish first began in the 1900s and became commercialized in the 1950s. Catfish is populous because of its health benefits and market demand. Farm-raised catfish are usually harvested at 18 months of age where as wild catfish usually get much bigger. There are a number of catfish species, but the three most prominent ones are blue catfish, channel catfish, and flathead catfish.
Tilapia is the third most popular fish used in fish farming or aquaculture, with the first two being carp and salmon. They have increased in popularity due to their high protein, large size and growth capabilities. Tilapia is a tropical fish that requires warmer water to survive. The ideal water temperature is usually between 28 to 30 degrees C. Tilapia fish are known to reproduce rapidly and this is a challenge for managing tilapia fish species for farming use. If not managed properly, fish will aggressively compete for food which may result in stunted growth. Therefore, males are almost used exclusively. Tilapias are resilient towards fighting off diseases and parasites. Tilapia fish require a cereal-based diet and don’t eat other fish, but they are also considered to be one of the most invasive fish species.
Salmon is one of the most popular fish species with the most commonly farmed being Atlantic salmon. There are two other varieties of Pacific salmon that are also farmed – Chinook and Coho. Farmed salmon are vaccinated to prevent disease outbreaks and only on rare occasions do they require additional medications. There are often questions about the different colours between wild and farmed salmon – farmed salmon aren’t dyed, their colour comes from their food. Salmon feed is made to conserve wild fish stocks.
Tuna fish are saltwater fish and are important in the commercial fish farming industry. Japan is the biggest consumer of tuna and has invested a significant amount of research into studying the fish. There are different species of tuna including, bluefin, yellowfin, and albacore. Bluefin tuna populations have dropped significantly in some regions due to over fishing. Farming tuna is complex as the fish are “massive” and are very active – so simulating their natural environment is extremely difficult. Most tuna for human consumption are caught in the wild and raised in a facility to increase weight gain. Tuna are carnivorous and eat other fish. Tuna are typically farmed in net pens offshore and in some cases are farmed in recirculation systems.
Eel fish farming emerged in the early 1950s and it is considered one of the most profitable in terms of export value in the fishing industry. However, the profit value is largely driven by the Asian markets and is culture specific. Eels are a carnivorous and catadromous fish, which means that when they are young they live in fresh water, but as they mature they migrate to the sea for breeding –spending anywhere from 8 to 30 years in freshwater before they migrate. The majority of eel farming takes place in Asia, with China, Japan and Taiwan leading as the biggest producers. Glass eels are preferred over elvers because they are easier to transport and wean onto artificial diets. Eel farming can take on one of two different forms – high intensity recirculating tank (indoors) or intensive pond facilities.
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Indoor fish farming
Indoor fish farming is the alternative to cultivating fish outdoors in a cage system. With the emergence of technological advances, raising fish indoors is now possible using proper control production methods. Indoor fish farming is often very sophisticated and in some cases allow for automatic collection and processing of fish wastes into crop fertilizers. There are advantages and disadvantages to indoor fish farming:
Advantages to indoor fish farming
- Fish are protected from predators and weather changes.
- Fish are often produced faster through temperature control, water quality and feeding practices.
- Indoor fish farming is often considered more environmentally friendly because it requires less water and produces less waste.
- Avoids the chance of fish escaping and getting loose amongst wild fish populations.
- Allows higher stock densities and often saved farm labour input costs.
- It often allows greater flexibility for facility locations, which can save transportation costs if facilities are located near markets.
Disadvantages to indoor fish farming
- Requires electricity input costs.
- Requires infrastructure set-up which often requires a significant amount of startup capital.
- Fish raised indoors are carnivorous, which requires the capture of large amounts of other fish for their diet.
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