How to Raise Salmon in Aquaponics

Who doesn’t love salmon? Salmon is one of the most consumed fish in the US. It is a great-tasting and healthy fish and is popular with anyone seeking a more nutritious diet. Raising salmon in your aquaponics system is possible, given the proper climatic conditions and enough space to grow. Growing salmon in aquaponics systems can be challenging, but the long-term benefits could be worth the effort. In this article, you will learn how to raise salmon in an aquaponics system. 

Why Raise Salmon in Aquaponics Systems?

Salmon is a great-tasting fish and is also packed with nutrients such as Omega-3 fatty acids, which are known for helping lower blood pressure, improve cell functions, and many more. However, many experts debate the healthiness of farmed salmon compared to the wild-caught variety. Raising salmon in aquaponics systems prevents the fish from growing in poor environmental conditions and potentially exposure to harmful chemicals. Making them more healthy than salmon caught in the wild. Here are the pros and cons of raising salmon in aquaponics systems.

Pros

1. Healthy Fish: Salmon is a good source of essential vitamins and minerals that help keep our body strong and healthy. 
2. Delicious Taste: Salmon is not only a healthy fish but also a delicious taste.
3. High Market Demand: Salmon is considered a top fish product and the second most-consumed seafood in the USA.
4. Social fish: Salmon can grow well with other fish, like trout.
5. Cold Tolerance: Salmon is well adapted to cold weather. So they are great for aquaponics systems that are located in a colder climate.

Cons

1. Temperature Control: Salmon, do not do well in warm temperatures, so if you live in a warmer climate, you must ensure that their water meets their ideal temperature range.
2. Picky Eater: Adult salmon are predatory fish and will only eat meat. Some of their food in the wild are smaller fish, squid, and shrimp. So if you're only growing salmon as a hobby, their food might be pricey.
3. Disease Prone: salmon are known to be disease prone.

Which Salmon Species is Best for Aquaponics

There are six common salmon varieties; Coho, Sockeye, Chinook, Chum, Pink, and Atlantic. Of all these varieties, the Atlantic salmon is recommended to be farm-raised because it is more closely related to trout. Atlantic salmon is also a tasty and disease-resistant fish and is widely sold in stores across the USA.

Factors to Consider in Growing Salmon for Aquaponics

Salmon is more challenging than the other common fish for aquaponics systems. This is why it is not recommended for aquaponics newbies. However, if you can provide a favorable environment for their optimum growth and survival, raising salmon in your aquaponics system can be very rewarding. Below are some factors you need to consider when growing salmon in your aquaponics system. 

• Stocking Density

Always keep in mind not to overstock your fish tank because this might cause fish stress, diseases, and other potential issues. The recommended salmon stocking density is based on the recommended fish mass of 20 kg per 1000 liters of water. Salmon can grow up to 58 inches long in size and weigh 126 pounds, so always consider the estimated size and weight of your mature salmon. 

• Fish Tank Size

A 1000 liters (264 gallons) is enough to contain four Atlantic salmon. A 20-gallon fish tank can also be used to start salmon eggs. 

• Feeding

You should provide different kinds of fish feed for each stage of development. These fish foods are classified as starter, grower, smolt transfer, and broodstock.

• Saltwater Cultivation

Salmon can dwell in freshwater and the sea. In the wilds, salmon are born in freshwater, develop at sea, and return to their birth streams to reproduce. This is why some commercial salmon growers relocate their fish into tanks that contain saltwater until they are ready for harvest. However, there are also many salmon growers who used freshwater from beginning to end and were successful.

• Breeding

Salmon are bred the same way as trout, where milt is collected from the male, while the eggs are collected from the female. Then the eggs are fertilized by mixing them with the milt. The water will activate the sperm, allowing for fertilization. The eggs will be fertilized at 39.2 °F - 51.8 °F and hatch in 6-20 weeks.

Requirements for Raising Salmon in Aquaponics Systems

pH Level: The ideal pH range for salmon is 6.5 to 8.5.

Water Temperature: Salmon are cold-water fish, and their ideal temperature is between 55 °F -65 °F.

Sunlight: Keep your fishtank from direct sunlight because it might heat up. Provide shade to your tank to maintain its temperature cool. 

Oxygen requirement: The ideal oxygen level for salmon is 6mg/l or higher of dissolved oxygen.

Fish Diet: Salmon are predatory fish and feed on smaller fish species in the wild. In aquaponics, salmon can be fed with commercial fish meals that contain 70% vegetables and 30% marine ingredients like fish oil and fish meal.

Feeding frequency: The feeding frequency will depend on your fish's water temperature and size. Fry need to be fed 8-12 times or more daily, but it decreases to 3-4 times a day as they mature. Hatchlings don’t need to be fed for 40 days because the yolk will serve as their food. 

Salmon Growth Rate: In the wild, salmon lay eggs in holes in the river bed and will hatch between 6 - 20 weeks after fertilization. Once hatched, the tiny alevins will live under the rock and feed on the attached yolk sac. The pink and chum salmon will head straight into the sea, while the other varieties of salmon will stay in the river for two years and then head to the sea. It can take up to 2 years for salmon to be fully grown. In the aquaponics system, it will take two years before a salmon can reach its full size, which is 20 inches.

Mixing with Other Fish Species: It is possible to mix salmon with other cold-water fish species like trout, as long as they are of the same size, 

Common Salmon Diseases: The most common diseases in farmed salmon living in poor conditions are red mouth disease and fin rot. The symptom of red mouth disease is hemorrhaging of the fins, eyes, and mouth. Diseases can be avoided by maintaining excellent water quality and healthy stocking density in your fish tank. 

How to Harvest Salmon

Salmon are carnivorous and will feed on smaller fish. So it is best to have several tanks to house fish of the same size and age. Having several tanks will also make you harvest salmon regularly at specific target dates. You can connect all the tanks, but to avoid diseases and infections from spreading to all your fish, have a valve that could disconnect the infected tank from the rest of the system. 

Once ready for harvest, you can starve the fish for up to three days before being harvested. Starving will clean the fish gut, help minimize fish stress and maximize the fish quality. 

What Aquaponics Plants are Best Suited for Salmon?

Salmon can be a great fish to grow cool-season crops like broccoli, collard greens, cabbage, lettuce, arugula, and other cool-weather plants. 

Conclusion

Raising salmon in your aquaponics system can be challenging. However, if you are up to the challenge and can provide their growing requirements, it can be a rewarding hobby. Thank you for reading our article. For more information about aquaponics, please read our blog, “The Ultimate Aquaponics for Beginner's Guide”.