A recent study led by researchers at Rutgers University has revealed that marine heat waves, prolonged periods of abnormally warm ocean temperatures, have not had a significant and lasting impact on the fish communities that support much of the world’s food supply. This discovery stands in stark contrast to the devastating consequences observed in other marine ecosystems following similar warming events, including widespread coral bleaching and harmful algal blooms.
Fish health management in aquaculture refers to the set of practices and strategies aimed at preventing diseases among fish. Once fish become ill, it can be challenging to save them.
Effective fish health management starts with disease prevention rather than treatment. Preventing fish diseases involves maintaining optimal water quality, providing proper nutrition, and ensuring good sanitation practices. Without these fundamental aspects in place, it becomes difficult to stop outbreaks of diseases that take advantage of weakened fish. Fish are constantly exposed to potential disease-causing agents like bacteria, fungi, and parasites, even if efforts are made to eliminate them through sterilization methods like ultraviolet treatment and ozonation. Subpar water quality, inadequate nutrition, or weakened immune systems due to stress provide openings for these agents to cause diseases. While medications can be used to treat such diseases, they are not a substitute for proper fish care.
Regularly observing fish behavior and feeding habits allows for early detection of issues, enabling diagnosis before the majority of the fish population becomes sick. If treatment is necessary, it is most effective when administered early in the disease’s progression, while the fish are still in good health.
The impact of fish diseases on aquaculture is significant in terms of financial loss. Disease outbreaks increase production costs due to losses from dead fish, the cost of treatment, and reduced growth during recovery. In natural environments, fish diseases have less noticeable effects because sick fish are swiftly removed by predators, and fish populations are less crowded than in aquaculture settings. However, when fish are densely packed and stressed in captivity, parasites and bacteria that are normally of minor concern in natural settings can lead to substantial problems.
It’s important to understand that fish diseases are typically not solely caused by pathogens infecting host fish; other factors and conditions must also be present for active diseases to develop within a fish population.
If you suspect that your fish may be falling ill, the first step is to assess the quality of the water in which they are kept. If you lack the necessary tools for water quality testing, reach out to your local county extension office. Some counties may have these testing kits available, and your extension agent can offer assistance. In cases where your county does not possess such kits, you can contact the nearest aquaculture extension specialist listed at the end of this publication. For those considering commercial fish production, it’s highly advisable to invest in a water quality test kit and acquire the knowledge to use it effectively. Even an introductory kit for freshwater aquaculture, which comes at a minimal cost, can potentially save you thousands of dollars in fish losses with its first use.
In ponds, low oxygen levels are a common culprit behind fish mortality, particularly during the summer. Disease outbreaks in crowded vats or tanks are often associated with elevated levels of ammonia. Additional fact sheets are available that provide explanations on oxygen and ammonia cycles, along with guidance on managing these water quality issues. Generally, when dealing with a fish disease outbreak, it’s essential to monitor dissolved oxygen, ammonia, nitrite, and pH as part of a basic water quality assessment. Depending on your specific system, parameters such as total alkalinity, total hardness, nitrate (for saltwater systems), and chlorine (if using city water) may also be significant.
It’s advisable to maintain daily records that can be readily accessed in the event of a fish disease outbreak. These records should include information such as the dates when fish were introduced, their initial size, the source of the fish, feeding rates, growth rates, daily mortality figures, and water quality measurements. This data is invaluable for aquaculture specialists working to address your fish health issues. Well-kept records, along with detailed observations of abnormal fish behavior and physical symptoms, as well as the results of water quality tests, provide a comprehensive case history for diagnosticians analyzing your situation.
If you decide to send fish samples to a diagnostic laboratory, it’s crucial to collect live, diseased fish and place them in a freezer bag (without water). These samples should be shipped on ice to the nearest facility. For smaller fish, they can be shipped while alive by placing them in plastic bags partially filled (around 30 percent) with water, and oxygen can be injected into the bag before sealing it. To minimize temperature fluctuations during transit, it’s advisable to use an insulated container when shipping live, bagged fish. In addition to fish samples, including a water sample collected in a clean jar for analysis is also recommended.
Fish diseases can be divided into two main categories: infectious diseases and non-infectious diseases. Infectious diseases result from the presence of pathogenic organisms in the fish’s environment or transmitted by other fish. They are contagious and may require treatment to control outbreaks. On the other hand, non-infectious diseases are caused by factors such as environmental conditions, nutritional deficiencies, or genetic abnormalities. These diseases are not contagious and typically cannot be cured using medications.
Infectious Diseases: Infectious diseases in fish can be further classified into parasitic, bacterial, viral, or fungal diseases.
Non-Infectious Diseases: Non-infectious diseases can be broadly categorized as environmental, nutritional, or genetic.
Summary: Fish diseases can pose challenges for both commercial producers and recreational pond owners. Many disease outbreaks in captive fish populations are associated with stressful conditions such as poor water quality, overcrowding, or inadequate nutrition.
A groundbreaking study published in the Journal of Agricultural and Food Chemistry has revealed a potential game-changer for those with shrimp allergies. Researchers at Dalian Polytechnic University’s National Engineering Research Center of Seafood conducted experiments using reverse-pressure sterilization on shrimp, exposing them to high pressure and steam. The result: a less-allergenic roasted shrimp product.
When mice with shellfish-consumption sensitivities were fed shrimp treated with reverse-pressure sterilization, they experienced milder allergic reactions and less organ damage compared to those fed raw or conventionally roasted shrimp. The study, supported by the American Chemical Society, highlights the possibility of using this technique to reduce allergenicity in other foods.
This breakthrough holds promise for addressing food allergies, potentially leading to the development of hypoallergenic versions of commonly allergenic foods like dairy, nuts, wheat, and various seafood. It sheds light on how the human immune system responds to foods it mistakenly perceives as threats
Food allergies affect millions of people, resulting in thousands of emergency department visits and hundreds of deaths annually in the United States alone. Reverse-pressure sterilization alters problematic proteins in a way that prevents overreactions from the immune system, potentially offering a safer future for allergy sufferers.
While roasting can achieve similar results in some foods, reverse-pressure sterilization appears to be particularly effective in inhibiting antibodies from latching onto allergenic proteins. This innovative technique may pave the way for a new era of hypoallergenic food products, offering relief to those living with food allergies.
During the monthly meeting of the Innovative Fish Farmers Association (IFFA) at the College of Fisheries, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, farmers were educated on the management of fish ponds, with special emphasis on environmental fluctuations during the monsoons.
The monsoon season management practices, including freeboard to accommodate rainwater, a maximum level sieved outlet to prevent stock escape/loss due to overflow, liming for pH control, dyke height to prevent flood water, along with unwanted polluting materials, from entering the catchment area, dyke strength to prevent dyke breach and stock loss, and entry of predatory/weed fish in the pond with canal water, were discussed by Vaneet Inder Kaur.
Abhishek Srivastava educated farmers about the significance of maintaining water quality to ensure the well-being and growth of fish. Meanwhile, Amit Mandal informed farmers about diverse approaches to sustainably develop aquaculture ponds and maintain an ideal population of natural food to boost productivity. Furthermore, they offered practical solutions and strategies to tackle snail infestations in fish ponds during the monsoon season in response to farmers’ inquiries.
Meera D Ansal, the College of Fisheries dean, highlighted that the monthly gatherings of IFFA serve as a means for farmers to stay engaged with the university, ensuring they receive regular technical updates and prompt solutions to their issues and inquiries. Furthermore, she emphasized that the valuable feedback provided by farmers aids in the development of targeted, regionally relevant problem-solving research.
Parkash Singh Brar, Director of Extension Education, mentioned that the forthcoming IFFA meeting will coincide with the upcoming Pashu Palan Mela at the university from September 14-15. During this event, the association will establish an exhibition booth to engage with fish farmers and other stakeholders involved in the fisheries supply chain. This interaction will benefit those looking to venture into fish farming as a primary enterprise or as an integrated subsidiary activity to enhance their income.
Aquaculture, the cultivation of aquatic organisms like fish, is a fascinating and economically significant industry that plays a pivotal role in meeting the world’s growing demand for seafood. However, just like any other form of agriculture, fish farming faces its fair share of challenges, and one of the most critical aspects is the health of the fish population. Fish are susceptible to a variety of diseases, infections, and parasites that can severely impact their growth and overall well-being. In this context, understanding different treatment methods, such as dip treatments and bath treatments, becomes paramount for fish farmers and aquaculture enthusiasts alike. In this guide, we will explore these treatment techniques, their applications, and the importance of precise execution in maintaining the health and vitality of your aquatic companions.
Gas bubble disease may occur due to nitrogen saturation in water, often resulting from rapid temperature changes. Fish fry, in particular, can experience high mortality rates. Affected fish may exhibit an angled swimming posture with their heads pointing downward. Symptoms may also include the presence of bubbles beneath the skin, on fins, around the eyes, in the stomach and intestine, or in blood capillaries. Remedies include agitating the water to reduce nitrogen saturation or transferring affected fish to other ponds. Supersaturated levels of oxygen have also been linked to gas bubble disease in fish.
Symptoms of vitamin deficiencies in fish can include scoliosis (curved spine), reduced growth, and anorexia (lack or loss of appetite). Signs of these deficiencies may manifest as low fish weight and lethargy.
Varieties of Treatment:
Immersion Treatment:
In the immersion treatment, fish are exposed to a relatively concentrated chemical solution for a brief duration, typically less than one minute. Here’s the procedure:
Bathing Treatment:
During bath treatment, fish are immersed in a diluted solution of the chemical for an extended period, which can range from a few minutes to up to one hour for short baths or even 24 to 48 hours for longer baths, especially in cases of very low chemical concentrations. Follow these steps:
(a) Short Bath:
For a short bath, mix the required amount of chemical with water in a plastic watering can. Lower the water level in the tank or circular enclosure by one-third to one-half. Gradually reintroduce water while evenly distributing the previously mixed chemical over the entire water surface. If necessary, stir the water with a clean broom, an agitator, or an aerator to ensure thorough dispersion of the chemical throughout the water column. Once the water returns to its usual level, treat for the recommended duration. Afterward, drain two-thirds of the water while resuming water inflow.
(b) Long Bath:
In the case of a long bath, halt the water inflow into the tank or pond. Reduce the water volume by draining some water, ensuring it’s at an appropriate level for the stock density and water temperature conditions. Calculate the water volume and determine the necessary chemical quantity. Dilute this chemical amount considerably, often at least 100 times, by mixing it in several plastic containers before application. Add this diluted solution to the tank or pond, making an effort to evenly disperse it over the entire water surface and thoroughly incorporate it with the pond water. Treat for the recommended duration. Subsequently, reopen the water inflow and elevate the water level to its normal state. If required, repeat the draining and refilling process.
In conclusion, proper diagnosis and timely application of the appropriate treatments are crucial for maintaining the health and well-being of your fish. Whether it’s through dip treatments or bath treatments, the care you provide to address various infections and diseases can make a significant difference in the vitality of your aquatic companions. Always remember to follow recommended procedures and guidelines to ensure the best outcomes for your fish population.