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Simple Summary: About a 4% decline in fish production was recorded in 2020 in comparison to 2018 in inland aquaculture sectors. In 2014, about 10% of aquatic cultured animals were lost (costing global annual losses > USD 10 billion) due to infectious diseases. Contagious diseases generate several stresses, including oxidative stress in fishes that hampers their reproduction, growth, and production value. Aquaculture management needs to employ preventive measures against various contagious diseases for maintenance. Therefore, vaccination in fish, especially in broodstocks, is one of the most important measures to curb such fish losses. Here, we reviewed the current status of fish vaccines and the modern technology used to produce (alternative) fish vaccines, such as plant-derived vaccines for fish health management. Reliable aquaculture vaccines to increase economic productivity in aquaculture sectors are needed. Emerging contagious diseases in different fish species demand novel vaccines to be produced by adapting biotechnological approaches. Vaccination in broodstocks is important, and the fish vaccines are produced with whole-killed pathogens; subunits of a protein, peptide, or a recombinant protein; DNA vaccines; or live attenuated vaccines via different modes of administration. The use of adjuvants in fish vaccines needs to be researched. Vaccination is an essential method of immunological preventive care required for the health management of all animals, including fish. More particularly, immunization is necessary for in-land aquaculture to manage diseases in fish broodstocks and healthy seed production. According to the latest statistics in 2020, 90.3 million tons of capture fishery production was achieved from the aquaculture sector. Out of the above, 78.8 million tons were from marine water aquaculture sectors, and 11.5 million tons were from inland water aquaculture sectors. About a 4% decline in fish production was achieved in 2020 in comparison to 2018 from inland aquaculture sectors. On the other hand, the digestive protein content, healthy fats, and nutritional values of fish products are comparatively more affordable than in other meat sources. In 2014, about 10% of aquatic cultured animals were lost (costing global annual losses > USD 10 billion) due to infectious diseases. Therefore, vaccination in fish, especially in broodstocks, is one of the essential approaches to stop such losses in the aquaculture sector. Fish vaccines consist of whole-killed pathogens, protein subunits, recombinant proteins, DNA, or live-attenuated vaccines. Challenges persist in the adaption of vaccination in the aquaculture sector, the route of administration, the use of effective adjuvants, and, most importantly, the lack of effective results. The use of autogenous vaccines; vaccination via intramuscular, intraperitoneal, or oral routes; and, most importantly, adding vaccines in feed using top dressing methods or as a constituent in fish feed are now emerging. These methods will lower the risk of using antibiotics in cultured water by reducing environmental contamination. [ABSTRACT FROM AUTHOR]

The world is projected to experience an approximate doubling of atmospheric CO2 concentration in the next decades. Rise in atmospheric CO2 level as one of the most important reasons is expected to contribute to raise the mean global temperature 1.4 °C-5.8 °C by that time. A survey from 128 countries speculates that global warming is primarily due to increase in atmospheric CO2 level that is produced mainly by anthropogenic activities. Exposure of animals to high environmental temperatures is mostly accompanied by unwanted acceleration of certain biochemical pathways in their cells. One of such examples is augmentation in generation of reactive oxygen species (ROS) and subsequent increase in oxidation of lipids, proteins and nucleic acids by ROS. Increase in oxidation of biomolecules leads to a state called as oxidative stress (OS). Finally, the increase in OS condition induces abnormality in physiology of animals under elevated temperature. Exposure of animals to rise in habitat temperature is found to boost the metabolism of animals and a very strong and positive correlation exists between metabolism and levels of ROS and OS. Continuous induction of OS is negatively correlated with survivability and longevity and positively correlated with ageing in animals. Thus, it can be predicted that continuous exposure of animals to acute or gradual rise in habitat temperature due to global warming may induce OS, reduced survivability and longevity in animals in general and poikilotherms in particular. A positive correlation between metabolism and temperature in general and altered O2 consumption at elevated temperature in particular could also increase the risk of experiencing OS in homeotherms. Effects of global warming on longevity of animals through increased risk of protein misfolding and disease susceptibility due to OS as the cause or effects or both also cannot be ignored. Therefore, understanding the physiological impacts of global warming in relation to longevity of animals will become very crucial challenge to biologists of the present millennium.