Every fish farmer knows that water temperature strongly influences fish metabolism. Therefore, the colder months of the year in subtropical countries are crucial for maintaining production, ensuring fish health, and resuming growth during warmer periods.
In this regard, fish farmers need to implement specific management strategies to optimize the performance of tropical and subtropical fish species.
In this context, the Department of Agriculture, Livestock, Sustainable Production, and Irrigation (Seapi) of the Rio Grande do Sul State Government has launched the e-book “MANEJO DE INVERNO PARA A PISCICULTURA NO SUL DO BRASIL” (Portuguese language) describing the practices that fish farmers should implement to raise tilapia during the coldest months of the year.
The book has been written by scientists from the Department of Agricultural Diagnosis and Research (DDPA/Seapi), Emater/RS-Ascar, and the Federal University of Santa Maria (UFSM). Its aim is to become a technical guide that directly addresses the main aspects of winter management for fish farming in southern Brazil but can be applied to other latitudes.
Tilapia Farming in Cold Climates
The book provides practical, technical, and scientific information to fish farmers, technicians, and researchers for pre, during, and post-winter management. While the document is focused on tilapia production, the information can also be applied to other species, including subtropical ones.
“Winter’s low temperatures can cause various problems in fish farming, such as reduced fish metabolism, increased mortality rates, decreased growth, and worsened diseases,” explained DDPA researcher Marco Aurélio Rotta, one of the authors of the publication.
The book lists a series of management recommendations to minimize the impacts of winter on fish farming.
“There are guidelines on planning and the necessary infrastructure for winter, nutritional and feeding management, health management, and water quality management, among other aspects,” detailed Rotta.
Planning for Winter
As we all know, we cannot control the weather, so we must try to mitigate (as best as possible) the extreme conditions that fish farming is subjected to.
In this sense, precautions and measures to reduce losses from low temperatures should start in the summer. According to the book’s authors, one of the critical actions to consider is the selection of species best adapted to the region’s climate.
The Arrival of Winter
To ensure that the arrival of winter does not have a negative impact on fish farming, several aspects need to be carefully considered, including:
- Avoid stocking ponds with fingerlings for fattening before winter and use juveniles weighing at least 30 grams.
- Supplement the feeding with vitamins (C and E) and probiotics to increase fish immunity. Selenium supplementation increases mucus production.
- Use feeds with high protein and energy content. Using pellets with smaller diameters also facilitates digestion.
During Winter
Cold temperatures decrease fish immunity, making them more susceptible to various diseases, including parasites. Therefore, during the winter period, you must pay closer attention to the fish and maintain good management practices to minimize losses.
Some recommendations include:
- Monitor the animals carefully to identify any changes in behavior (e.g., loss of appetite) and mortality.
- Ensure excellent water quality in the tanks. Probiotics can be used to minimize the accumulation of organic matter.
- Plan stocking before winter with a density compatible with the tank’s capacity during this period.
- Pay greater attention to feeding, ensuring the provision of adequate feed quantities. Feeding rates should be reduced according to the water temperature.
End of Winter
This period of temperature increase, marking the end of winter and the beginning of spring, is crucial in fish management, aiming to initiate breeding activities or resume commercial volumes, particularly for tropical species.
The book’s authors recommend paying attention to the following aspects:
- Monitor nitrogen compounds in the cultivation water.
- Monitor the temperature increase as it will have a significant influence on water quality.
- Avoid over-fertilizing the tanks during this period; excessive fertilization can be toxic and potentially fatal for the fish.
Final Considerations
“This publication provides an overview of actions that can minimize the impacts of low temperatures on fish farming, focusing on tilapia, as it is a fish with great potential but more sensitive to low temperatures,” describe the authors.
According to the researcher, although the book focuses on tilapia production, the information contained in the publication is relevant to other species, including subtropical ones.
Reference (open access)
Marco Aurélio Rotta, Andréa Ferretto da Rocha, Benito Guimarães de Brito, João Alfredo de Oliveira Sampaio, Kelly Cristina Tagliari de Brito, Lissandra Souto Cavalli, Rafael Lazzari. 2023. MANEJO DE INVERNO PARA A PISCICULTURA NO SUL DO BRASIL. 1. ed. Porto Alegre: DDPA, 2023. 149 p.
