The occurrence of disease in aquatic animals is an ever-present economic threat and management challenge to the Aquaculture industry. The impact from disease can affect aquatic animal health, animal welfare, trade, and even human health. In the current pandemic it seems clear that the detection, prevention, control and eradication of key aquatic animal diseases have now become critical actions for the sustainability of global seafood production.
Biosecurity refers to measures aimed at preventing the introduction and/or spread of harmful organisms such as viruses, bacteria or parasites to animals and plants, in order to minimize the risk of transmission of infectious disease. These include surveillance and testing, educating and advising producers on disease risks, implementing disease control strategies, the development of biosecurity plans, cleaning and disinfection procedures, and preventing zoonotic disease transmission.
In view of the present circumstances, critical thinking becomes essential for the realization that a lack of institutional and technical capacities limits the application of effective biosecurity measures. Among these are weak regulatory frameworks, poor enforcement and implementation of international standards, little coordination between the multiple institutions involved in aquaculture production and aquatic animal health management (i.e. fisheries, aquaculture and veterinary authorities); inadequate or partially implemented biosecurity strategies at the farm, sector and national levels; and absent or insufficient capacity for response to emergencies.
The growing international trade in aquaculture seed for key species such as the rainbow trout, salmon, seabass, seabream, tilapia, eels, oysters, clams or shrimp remains a pillar for the expansion of an activity which has consistently outperformed any other type of farming during the last decades. Ensuring the biosecurity of aquaseed thus acquires crucial importance as producers and retailers must keep updated on products and regulations for their own sake.
For many years, disinfectants have been successfully used at the hatchery stage. The objective is to improve hatchability and profitability through the destruction of disease-causing microorganisms on the outer coating of the gametes, without damaging them. This is particularly important for exporting hatcheries. However many disinfectants are designed to kill extremely tough and resistant pathogens, rendering them environmentally hazardous. The selection of the appropriate active principles in the correct formulations is therefore of great importance. The incorrect choice can lead to undesired mortalities, poor biodegradability and subsequent environmental damage.
In the 1970’s, the buffered iodine disinfectant, ‘Buffodine’, was invented by UK manufacturer Evans Vanodine. This was specifically designed to kill viruses such as IPN (Infectious Pancreatic Necrosis) on the outer membrane of salmonid eggs, without penetration or damage to the chorion. Buffodine was the first of this disinfectant type to be developed and was patented, and since then this class of product has been largely used for egg disinfection by salmonid and other marine species producers around the world. The product displays effectiveness on a wide range of fresh water and marine species, including fish, shellfish and crustaceans, to prevent infection.
However, the use of these disinfectants has not been specifically controlled by regulation, even though they are very effective in providing low levels of mortality in broodstock, enhancing hatching rates and preventing the transmission of disease throughout the world. This has recently changed as in Europe, the use of all disinfectants is now controlled by the European Union Biocidal Products Regulation (BPR) (EU 528/2012). This regulation, which applies to all EU member states (and to other countries which have adopted the regulation, such as Norway) evaluates the disinfectants and authorizes them for specific uses. If authorization is given, manufacturers of the finished product must then apply for Mutual Recognition of the authorization in any member states in which they wish to sell the product. The BPR authorization is a long, complex and expensive process, aimed at standardizing the use and effectiveness of disinfectants across Europe, making it safer for users and restricting the use of potentially hazardous or environmentally unsafe compounds. Iodine was the first active ingredient relevant for aquaculture to be authorized by the European Chemicals Agency (ECHA) and disinfectant formulations based on this compound are now being approved by the Member States. The high cost and technical demands of submitting product dossiers to the EU in support of a specialist egg disinfection product has caused most, if not all, other manufactures to withdraw their products from the market. Currently, Buffodine is the only authorised fish egg disinfectant in Europe (authorized biocide: UK-2019-1172).