Special section on aquatic animal health and disease

Aquaculture is the cultivation of aquatic organisms, especially for food consumption. In 2021, global aquaculture production constituted ~126 million tonnes with an estimated value of $296.5 billon (USD), ¹² which includes edible aquatic species and non-edible products such as shells and pearls. Aquaculture production is largely driven by the cultivation of finfish (47.1% of global production in 2021); however, other significant contributors include seaweed (27.9%), mollusks (14.6%), and crustaceans (9.4%). ¹² This growth has been driven largely by a corresponding increase in the global consumption of aquatic foods, with the world now consuming > 5 times the amount of aquatic foods than was consumed ~60 y ago (~28 million tonnes in 1961) and with the annual growth rate being at least double that which could be expected from population growth alone. Aquaculture production continues to increase annually and, in some countries, now exceeds capture fisheries. ¹²

In addition to food production, aquaculture (freshwater and marine) also includes captive breeding and rearing of ornamental species for home or public-viewing aquaria. ¹³ It is worth noting that the ornamental fish trade also involves the capture and removal of numerous fish species from the environment. It is difficult to ascertain the exact value of the ornamental fish trade due to deficiencies in trade data; however, most estimates suggest the value of the ornamental fish trade (including supporting accessories) to be in the billions of dollars.^1,8,15 The United States is the largest importer of ornamental fish in the world; many fish are harvested or exported from countries in Asia including the Philippines, Japan, Singapore, Indonesia, and Sri Lanka. ⁸ Estimates place the number of ornamental fish traded annually from the hundreds of millions to upwards of 1.5 billion, with up to 73% mortality during transportation.^2,19

Fish and other aquatic organisms also represent important laboratory animals with a variety of species being particularly well suited for environmental and experimental biomedical research studies. Teleost fish again represent the most utilized with zebrafish (Danio rerio) being a particularly well-known laboratory animal species; zebrafish are now often the second most common laboratory animal species used in biomedical research in some countries.

One of the most significant challenges facing the aquaculture industry, the trade in ornamental species, and our laboratory populations is the prevention, detection, and treatment of disease. Additionally, there is increasing concern regarding the health and welfare of pet and laboratory fish.^10,17,18,21 As a result, there is a significant need for veterinarians and diagnosticians within the field of aquatic animal medicine. We hope that this special section on aquatic animal health and disease will be helpful as we highlight several novel/emerging pathogens,^4,6,14 new detection assays,^7,16 and pathology within a wide range of aquatic species.^{3,5,9,11,20,22}