For you to raise crayfish in aquaponics, you have to observe specific factors that lead to a profitable harvest of crayfish. Like any other aquaponics farm, the quality of water directly influences how healthy your fish tank will be, which also affects the well-being of the plants in your grow bed.
What is the difference between lobster and crayfish?
Lobster is often confused with crayfish and vice versa. The situation is quite understandable since both crustaceans have similar characteristics. However, there are still some features that differentiate the two.
Crayfish is a nocturnal crustacean that resembles a lobster, yet its habitats are freshwater environments such as streams and rivers. On the other hand, a lobster is a saltwater species of the same group. It has a cylindrical body, stalked eyes, and has modified pincers at its first limbs.
Due to the similarity of these two, crayfish is also called "rock lobster," which I will discuss in this post since saltwater animals are not recommended for aquaponics.
Why raise crayfish in aquaponics?
Crayfish (also known as crawdads, crawfish, or freshwater lobsters) are freshwater crustaceans that resemble a small lobster. They may not be as popular in aquaponics systems as other fish species, but they have been successfully raised in thriving aquaponics installations. Crayfish might be a cheap approach to add a distinctive touch to your system because they are readily available.
What species of crayfish are available for aquaponics?
While keeping crayfish in your aquaponics system can be entertaining, many species cannot flourish in captivity. Consider the following species if you are pondering about introducing crayfish to your fish tank:
- Red claw — This species is native to Northern Australia, and it comes in a wide range of colors, from blue-green to practically black, with yellow lines or spots. They can grow to be 8.5 inches long, so they'll need to be kept in a bigger tank.
- The Miami Cave Crayfish - This crayfish is a bright to pale yellow-orange colored species that is native to Miami, Florida. They barely reach a maximum of three inches, yet they are considered a more tolerant crayfish species.
Which species of crayfish is best for aquaponics?
The well-suited species of crayfish for aquaponics is the red claw. Redclaw has several morphological, ecological, and commercial characteristics that make it a great aquaponics species. It has a vast geographic potential, a simple life-cycle and easy production method, requires a low-protein diet and is cost-effective to produce. Its texture and flavor are similar to that of regularly consumed marine crustaceans. Finally, it is positioned at the high end of the crustacean market due to its lobster-like appearance.
What are the factors to consider in growing crayfish in aquaponics?
In growing crayfish for an aquaponics setup, the following factors should be appropriately observed:
Stocking density
You can roughly raise 8 - 10 crayfish per square meter. These crustaceans want space to move about, so a stocking density of 5 gallons of water per crayfish is appropriate. The stocking density for larger species is 15-20 liters of water per crayfish.
Tank size
A 25-gallon tank can hold one Red Claw Crayfish, whereas a 40-gallon aquarium can have two. A tank at least 40 inches long and 20 inches deep is required for the larger Australian Redclaw Crayfish.
Water temperature
Red claws are native to northern Australia's tropical region. As a result, red claw thrives in warm water at about 75 to 85 °F (24 to 29 °C) and will not tolerate low temperatures. The pace of growth is considerably slowed when the water temperature falls below 70 °F (21 °C).
pH range
Redclaw thrives in a pH range of 7 to 8.5. Molting and shell hardening issues may occur at levels below 7.
Dissolved oxygen
It's worth noting that crayfish require a lot of oxygen. They will climb up to acquire oxygen from the air if you fail to have a filter or an airstone. They will drown if they do not have a way to get out of the water. If possible, dissolved oxygen levels should be maintained above two parts per million (ppm).
Feeding requirement
Red claws eat a wide variety of things, including rotting plant and animal detritus, macrophytes, benthic invertebrates, algae, bacteria, and fungi. This fact could allow natural foods or forages to supplement or replace pricey prepared diets.
What are the pros and cons of growing crayfish in aquaponics?
Crayfish aquaponics brings to the table a set of advantages and disadvantages which you should take into consideration before deciding to use it in filling your fish tanks. Here are some of those pros and cons:
Pros:
- It reproduces quickly and has no larval stage.
- High stocking densities are tolerated.
- It necessitates a low-protein diet and is not dependent on fishmeal.
- The texture and flavor of the flesh are superior to that of other crabs.
- Tolerant water quality variations include low dissolved oxygen, significant daily pH shifts, low alkalinity, temperature changes, and heavy nutrient loading.
- The species is omnivorous, which means it is not a picky eater.
Cons:
- They are bottom feeders, which means at some point, you need another aquatic animal to deal with foods found at the water surface.
- In some countries, crayfish breeding is regulated by law because they can become invasive species. A 2016 Science journal mentions this fact. Since this is the case, it would be helpful for you to determine any regulations your region has against crayfish aquaponics.
How to harvest crayfish in aquaponics?
Harvesting crayfish implies using large dip nets that fit your yield. I also advise that you use protective gloves because they may nip your fingers when frightened.
Choosing crustaceans as aquatic animals of your aquaponics setups is an excellent choice. Crayfish is a perfect addition to your fish tanks occupants because they are easy to manage and maintain. But this does not mean that you can be lax in raising crayfish. Consistent monitoring of water quality is still an essential aspect of success in crayfish aquaponics.
