Dear friend Senthilkumaravelan Ayyar

The presence of Thalassiosira weissflogii diatoms in the shrimp larval rearing tank can indeed cause the water to appear green. Diatoms are a type of microalgae that are known to contain chlorophyll, which gives them a green coloration. When they proliferate in large numbers, the water can take on a greenish hue.

However, it is important to note that the presence of diatoms alone does not necessarily lead to high mortality rates in shrimp post larvae. Diatoms are a natural part of the aquatic ecosystem and can provide a food source for shrimp larvae. In fact, some species of diatoms are commonly used as a feed source in shrimp hatcheries.

The impact of diatoms on shrimp larvae depends on various factors, including the species of diatoms present, their abundance, and the overall water quality conditions in the rearing tank. It is possible that other factors, such as water quality parameters (e.g., temperature, pH, dissolved oxygen), presence of other microorganisms, or inadequate nutrition, may be contributing to the mortality rates observed.

To better understand the specific effects of diatoms and the potential correlation with mortality rates in shrimp post larvae, it is advisable to consult scientific literature and research studies that focus on shrimp larval rearing, water quality management, and the role of microorganisms in aquaculture systems. These references can provide more detailed insights and specific findings related to your inquiry.

Too much light, you need to adjust the photoperiod better.

@all Yes, Thalassiosira weissflogii diatoms can contribute to a change in the color of the shrimp larval rearing tank water, typically turning it green. Thalassiosira weissflogii is a common species of marine diatoms that are known to form extensive blooms under favorable conditions.

The green color of the water is primarily due to the presence of chlorophyll in the diatoms. Chlorophyll is the pigment responsible for photosynthesis in plants and algae, including diatoms. When Thalassiosira weissflogii diatoms grow and multiply in large numbers, the concentration of chlorophyll in the water increases, resulting in a greenish hue.

Diatoms, including Thalassiosira weissflogii, require light for photosynthesis. They utilize nutrients, such as nitrogen and phosphorus, along with carbon dioxide and sunlight, to grow and reproduce rapidly. When the conditions in the shrimp larval rearing tank are favorable, including sufficient light and nutrient availability, diatoms can flourish and lead to the green coloration of the water.

To control the overgrowth of Thalassiosira weissflogii and prevent excessive greening of the water, you can implement the measures mentioned earlier:

It's important to note that diatoms, including Thalassiosira weissflogii, are not necessarily harmful to shrimp larvae. In fact, they can serve as a valuable food source for the larvae, providing essential nutrients. However, if their population becomes too dense, it can impact water quality and oxygen levels, potentially leading to imbalances and other issues.

Regular monitoring of water quality parameters, including dissolved oxygen, pH, and ammonia levels, along with observation of the shrimp larvae's behavior and health, is crucial to ensure a suitable rearing environment. Adjustments should be made as needed to maintain optimal conditions for the larvae's growth and development.

@all Apologies for the confusion in my previous response. You are correct that Thalassiosira weissflogii diatoms typically produce a brown color tint in the water rather than a green color. I apologize for the oversight in my previous explanation.

In the context of shrimp larval rearing tanks, the presence of a green color in the water is more commonly associated with the overgrowth of green algae, such as species from the genera Chlorella, Nannochloropsis, or Tetraselmis. These green algae can proliferate under favorable conditions and lead to the water turning green.

Excessive green algae growth can have various impacts on the larval rearing tank and the shrimp post-larvae (PL). While green algae themselves are not usually directly harmful to shrimp larvae, their overgrowth can indirectly affect the larvae and potentially lead to high mortality rates. Here are some possible reasons for the negative effects:

To prevent or manage excessive green algae growth and mitigate potential risks to the shrimp larvae, you can consider the following measures:

By maintaining optimal water conditions and preventing the overgrowth of green algae, you can help reduce stress on the shrimp post-larvae and minimize potential mortality rates.