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If you are new to culturing fish, it might surprise you that some fish species possess an unusual characteristic of eating their young. This phenomenon is called filial cannibalism and is often caused by population and environmental factors. Although research has been conducted on this subject, minimal literature focuses on the occurrence of this trait on common aquaculture fish like tilapia. It is for this reason why this article focuses on whether tilapia will eat their young depending on their living condition.
While tilapia are known to produce a lot of eggs, not all of these eggs reach the fry or fingerling stage. This is because they are eaten by their parents or other adult tilapia present in the breeding pond or tank before they are transferred. The most common reason why tilapia eat their young is that they have a huge appetite, and they consider them as a great source of protein.
This article will aim to explain more about this phenomenon that occurs not only in tilapia but with other fish species as well. The factors influencing filial cannibalism as well as the ways to mitigate it are discussed in detail below.
Explaining filial cannibalism
According to a journal published in Science Direct, some animal parents tend to exhibit filial cannibalism which is the act of killing, deserting, or aborting their offspring. The primary hypothesis related to this is the Energy-based Hypothesis which states that parents eat their young because of the potential nutritional benefits that they will gain. However, several studies suggest that some male parents do this because of endocrinological necessity. For them to restart courtship, they need to regulate their androgen levels by getting rid of all the eggs. This draws the line between total and partial filial cannibalism.
Total filial cannibalism
In total filial cannibalism, parents eat their young for future reproductive success. In other words, they abandon all of their offspring so that they can prepare for courtship and begin the next reproduction phase. Some believe that this should no longer be called cannibalism but infanticide or embryocide.
Partial filial cannibalism
Partial filial cannibalism differs from the former in such a way that the parents only eat a portion of their eggs to make up for the energy they lose in caring for their eggs. This type of cannibalism is believed to improve reproduction as well, but the main benefit from this is that the remaining offspring has a higher chance of surviving.
Factors influencing filial cannibalism in fish
Many factors affect filial cannibalism in fish, aside from what we have mentioned earlier. According to research published in the Springer Link, there are two bases of cannibalism which includes population and environmental factors. The population factors include the following:
- Genetic background
- Size of larvae
Meanwhile, the environmental factors that are believed to affect filial cannibalism are:
- Light conditions
- Colour and shape of tanks
Will tilapia eat their young like other species?
Tilapia is an omnivorous species. It consumes both fish and plants for its diet that’s why it is no wonder it exhibits filial cannibalism. When hungry, tilapia would eat any food item available in their tank, but in some cases where food is not readily available, they choose to consume their young.
The rate of filial cannibalism on tilapia is seen to be higher on non-spawning adults, and most of the time, the more cannibalistic tilapia are those that are from the previous spawn. So this is not just a parental case but also in between siblings. Because of their huge appetite, they often see other tilapia as an excellent protein source, so they consume them as long as they fit in their mouth.
Mitigating cannibalism in tilapia
Several ways should be strictly followed to mitigate the occurrence of filial cannibalism in a tilapia pond or tank and increase the practitioner’s harvest. These approaches are proven effective in lessening tilapia mortality, especially when applied simultaneously. However, the practitioner may choose to focus on a specific method if he identified a particular reason that significantly affects the rate of filial cannibalism in his tank.
Maintaining correct stocking density
The population density of tilapia significantly affects its cannibalistic behavior. Since tilapia produces a lot of eggs in just a single spawn, the tank is usually full, resulting in parents eating their young. Abiding by the appropriate tilapia density standards will help alleviate their cannibalistic behavior.
Applying fingerling grading
Fingerling grading is a necessary step in raising tilapia fingerlings as well as in preventing filial cannibalism. By doing size-sorting, the practitioner is eliminating dominance hierarchies present in the tanks, which also contributes to cannibalism.
Following appropriate feeding and supplementation
If the grower is applying good feeding practices and ensuring that the fish are given enough supplements for a nutrient boost, the occurrence of cannibalism will be lessened dramatically. There are many available food pellets and supplements to choose from in local fish stores and Amazon.
Another factor that has a high impact on filial cannibalism is temperature because it affects tilapia’s metabolism. Once the temperature rises, the demand for food is also higher. Thus, resulting in increased instances of parent fish eating their young.
Designing refuges for weak and developing fish
Providing refuges for weak and developing fish proves to be efficient in lessening cannibalism as well as territorial aggression among tilapia species, specifically in the pond culture. However, the practitioner should make sure to construct the right size to prevent the fish from fighting for refugees.
Tilapia exhibits filial cannibalism which is either a result of the high population in the tanks or pond or due to other environmental factors. One of the most common reasons why tilapia eat their young is because they find them a good source of protein when they are hungry. There are several ways that we have listed above to mitigate tilapia cannibalism. This involves maintaining correct stocking density, applying fingerling grading, following appropriate feeding and supplementation, regulating temperature, and designing refuges for weak and developing fish. If not implemented correctly, tilapia will eat their young, which will result in a poor harvest.