Vannamei shrimp farming has flourished in Indonesia and is becoming a promising aquaculture venture. Vannamei shrimp, also known as whiteleg shrimp, holds high economic value for both domestic and export markets. However, successful cultivation of this shrimp isn't solely dependent on pond and environmental management, but also on the seeds' quality. A crucial stage in the cultivation process is the selection of postlarvae shrimp (PLs), which are vannamei shrimp seeds approximately 15-20 days old after the spawning process.

At this stage, PLs have the potential to develop into adult shrimp when raised under optimal conditions. Carefully chosen PLs will thrive in the pond and yield abundant harvests. Conversely, using low-quality PLs can lead to slow growth, diseases, and even mortality, causing losses for farmers. Therefore, understanding how to select healthy and high-quality PLs is vital.

While environmental factors like water quality, temperature, and feed provision significantly influence farming success, these factors must be complemented by good seeds. Healthy and high-quality seeds have a higher chance of survival and optimal growth. Hence, this article will delve deeper into the characteristics and traits of vannamei shrimp PLs suitable for cultivation, along with tips on choosing the best PLs to maximize harvest yields.

The right time for PLs stocking

Vannamei shrimp PLs are shrimp seeds that have undergone several developmental stages. One critical aspect to consider when selecting PLs is their age. PLs are categorized based on age, and the ideal age for stocking in ponds is between 18 and 20 days. At this age, vannamei shrimp have completely shed their larval shells and are entering a more mature developmental phase. When PLs reach this age, they possess a more complete body structure and are ready to adapt to the pond environment. The term PL followed by a number, such as PL-10 to PL-12, is used to indicate the shrimp's age since shedding its larval shell.

The size of PLs at this stage is still very small, not even reaching 1 cm. Nevertheless, high-quality PLs can be identified by certain physical signs. One observable indicator is the well-formed gill structure, clearly visible through the transparent body of the PLs. Additionally, internal organs like the gut can also be seen with the naked eye, providing a crucial clue for assessing the health of the PLs. The transparent body of PLs allows farmers to examine the condition of their internal organs, making it easier to determine if the PLs are in a healthy state.

Vannamei shrimp fry swimming against the current: supplierbenur

Swimming ability is another vital factor in evaluating the quality of vannamei shrimp PLs. Healthy PLs should exhibit strong and stable swimming capabilities. They should be able to swim against the water current, demonstrating that their muscles and nervous systems have developed well. On the other hand, PLs that are easily carried away by the water current indicate physical weakness or health problems that could affect the shrimp's future development. Additionally, healthy PLs are generally more active and responsive to stimuli from their surroundings. Active swimming behavior signifies that the PLs have sufficient energy and are not under stress. 

Uniform size

Uniformity in PLs size is a key indicator of the quality of vannamei shrimp seeds. PLs with uniform sizes signify that their growth has been normal and undisturbed. This uniformity is important because PLs growing at the same pace tend to be healthier and have better resilience. Conversely, if there are size differences among the stocked PLs, shrimp growth in the pond can become uneven. Smaller shrimp may struggle to compete for food, which can ultimately slow their growth and increase the risk of mortality.

Furthermore, the uniformity of PLs size significantly affects the efficiency of the harvesting and selling process. If the stocked PLs have varying sizes, the resulting shrimp will also vary in size. This can make it difficult for farmers during harvest time, as shrimp that haven't reached the ideal size must be separated from those ready for harvest. Size differences will also impact the shrimp's market value, as the market prefers shrimp with uniform sizes.

Perfect physical form

Healthy and high-quality vannamei shrimp PLs have distinctive physical characteristics that are easily recognizable, one of which is their firm and straight body shape. Unlike some other shrimp species that might have a slightly hunched posture, healthy vannamei shrimp typically have a straight body when swimming. This indicates that the shrimp's muscles have developed well and are free from structural abnormalities. When PLs swim with a straight posture, it's a sign that the shrimp are in optimal physical condition and ready to thrive in a larger pond environment. This good physical condition will also influence the shrimp's ability to grow quickly and healthily.

In addition to a firm body shape, the condition of the eyes and the transparent body are also important indicators for assessing PLs quality. Healthy PLs usually have clear eyes and no blemishes or spots on their bodies. The transparent body allows farmers to examine the condition of internal organs, like the gut, which should also be visible and full. If there are stains or spots on the PLs' bodies, this could be a sign of infection or health problems that may affect the shrimp's development in the future.

Healthy and physically perfect PLs: Banglele Indonesia

Apart from body shape, the antennae and tail of PLs are also crucial aspects in determining shrimp quality. Intact antennae, not broken or damaged, indicate that the PLs are in good condition. Antennae serve as vital sensory tools for shrimp to interact with their environment, so damage to the antennae can affect the shrimp's survival ability. A fully opened tail in PLs is also a sign that the shrimp is ready to be stocked in the pond. An open tail signifies that the PLs have reached a sufficient developmental stage to face the conditions of the cultivation pond, and if the tail is still closed, it's best to postpone stocking the PLs until the tail opens.

A full gut

One easy indicator to identify healthy vannamei shrimp PLs is to observe the contents of their stomach or gut. In healthy PLs, the gut will appear full, indicating that the shrimp is actively feeding and in good condition. A full gut suggests that the PLs have a normal metabolism and are ready to grow larger after being stocked in the pond.

Conversely, if the gut appears empty, it could be a sign that the PLs are stressed or sick, leading to a reduced appetite. PLs with empty guts tend to have lower survival rates, as this condition indicates a nutritional imbalance that can disrupt their development and resilience.

Tips for choosing quality PLs

Before starting the vannamei shrimp cultivation process, farmers must conduct a thorough observation of the quality of the PLs to be used. One highly recommended initial step is sorting. This sorting process aims to ensure that only quality PLs are stocked in the pond. Healthy PLs have a higher chance of survival and growth, making sorting a key to successful cultivation. By performing this selection, farmers can reduce the risk of spreading sick or weak PLs, which can affect overall cultivation productivity.

PLs sorting process: Banglele Indonesia

Besides sorting, physical observation of PLs is also very important. Quality PLs can be recognized by several clear physical signs. One main characteristic is uniform size, where PLs that grow normally will have relatively the same size. The bodies of healthy PLs also appear straight when swimming, unlike unhealthy PLs that tend to be hunched or bent. Bright eyes and a transparent body without blemishes or spots also indicate that the PLs are in prime condition. Additionally, a full gut signifies that the PLs have a good appetite and are in good health, which is a good sign for their subsequent growth.

To further ensure the quality of PLs, a swimming response test can be conducted. This is done by providing stimuli through water movement around the PLs. Healthy PLs will show a quick reaction and actively swim against the water current. They also tend to cling to the bottom of the pond, demonstrating their good resilience to the cultivation environment. A good response to these stimuli indicates that the PLs have the strength and ability to survive in a larger environment, making them better prepared to face the more challenging cultivation process.