...refreshment anyone?

profiair OxyTwist 750

profiair OxyTwist 750 – also known as paddlewheel aerator –sets new standards in the aeration.

Sets new standards in the aeration of production ponds, spa garden ponds, and sewage treatment plants. Apart from oxygenation and gas exchange, profiair OxyTwist 750 with its 2 paddlewheels will create water current.

profiair OxyTwist 750 improves the water’s quality measurably and visibly, and significantly reduces algal growth. Due to the water quality improvement realized by profiair OxyTwist 750, it contributes to increased yields from your production ponds.

profiair OxyTwist 750 is delivered as assembly kit.

be prevented. In this context, the temperature and the oxygen content in the water are of particular importance. ese master factors must always play a central role in preventive biosecurity and health management.

Examples from trout farms in Baden-Württemberg show how important a good oxygen supply is. By aerating the sh tanks with pure oxygen, not only could the water volume be used optimally, the water quality improved, the stocking densities increased and thus the pro tability of the farms increased, but the health and resistance of the trout to the Aeromonas and Pseudomonas bacteria was also signi cantly strengthened. Since then, furunculosis has almost completely disappeared.

Preventive vaccinations strengthen the immune system

Vaccines, which stimulate a strong protective immune response against certain pathogens, are also gaining importance as a management tool in the toolbox of disease prevention. Such vaccines already play a certain role in marine salmon trout farming, but they are still largely irrelevant in freshwater. is is probably also due to the fact that there are hardly any commercial vaccines available for trout farming. In addition, they are sometimes controversial in the industry and not approved everywhere. Nevertheless, immunization by vaccination could be an important and promising future preventive approach that belongs in the “ rst line of defence” of disease management. In addition, vaccinations are better than reacting to the outbreak of a disease with chemicals or even antibiotics.

We’ve come a long way with the use of functional feeds and some alternative products that boost the immune system of sh whilst improving their resistance to stress and disease. e range of products in this area are now so diverse and extensive that it is often di cult to separate scienti cally proven and e ective remedies from dubious alternatives that probably only serve to increase the bank accounts of their providers. Since there are undeniable links between chronic stress, weakened immunity and increased susceptibility to disease, a lucrative market is opening up for products that are designed to elicit physiological responses that could improve the overall health status of sh. Probiotics that are added to the feed that reduce bacterial loads or increase host resistance are widely used. Prebiotics in the feed promote a healthy microbial ora and so-called postbiotics, which contain antimicrobial peptides or polysaccharides, act against bacterial pathogens. Various herbs and spices and their derivatives are said to have similar health-promoting properties. But how do you properly assess the health and welfare of trout? Are there any objective criteria that provide reliable information on this subject? Absolutely – and for free even! For example, a 130-page manual in English and Norwegian has been available to download on the No ma website since 2020. is handbook allows trout farmers to assess the welfare of their sh using “indicator toolboxes”.

EU animal health law regulates the obligations of companies

On April 21, 2021, Regulation EU 2016/429 (Animal Health Law) came into force. is replaced the Directive 2006/88/EC, which previously regulated the obligations of European trout farmers. e new regulation aims to harmonize the principles of disease monitoring and control throughout Europe and to make them clearer, streamline content and clarify ambiguities. e new Animal Health Law, which regulates almost everything from the export of horses, goats and deer to the border crossing of carrier pigeons, has been ambitiously adopted, but this resulted in a bureaucratic monster that is di cult to understand and leaves many questions in practice. Producers and exporters of “aquatic animals”, which include crustaceans and molluscs in addition to sh, have to tediously search text after text just nd the legal requirements and obligations that apply to them. Luckily, relatively little has changed for sh and trout farmers. Most farms, from the hatchery to the fattening facility, must continue to meet the high standards of biosecurity that have existed up to now. All activities of parties involved must be aimed at preventing the spread of sh diseases at the national and international level.

e obligation to keep records of incoming and outgoing sh stocks remains in place, as does the obligation to report animal transports. For the transport of sh within the EU, TRACES certi cates must be issued by the competent veterinary authorities. e electronic database system TRACES (Trade Control and Expert System) was set up throughout the whole of the EU on the basis of the Decision 2003/623/EC42. e obligation to notify and report particularly dangerous sh diseases, which form the basis for government preventive and control measures, also remains in place. In the case of trout and other salmonids, this applies in particular to listeriosis and salmonellosis, ISA, EHN, IHN, and VHS. Registered and licensed aquaculture companies are required to keep records of unusually high mortality rates in trout stocks. If an increased mortality rate is found that cannot be clearly attributed to certain husbandry or transport conditions, this must be reported to the competent authority immediately.

Acting quickly in the event of disease reduces consequential damage

Despite all caution, disease outbreaks can occur even in wellmanaged trout farms. Early recognition of symptoms and rapid action is important to prevent damage to sh stocks and limit economic losses. In order to be able to initiate the necessary measures, every sh farmer should have a basic knowledge of the most common diseases, how to identify them and immediately treat them. An extensive arsenal of clearly illustrated specialist literature is also available to support them, showing the characteristic features and damage symptoms of the diseases. As a result, in cases of an outbreak of any disease, initial assumptions of its nature can be drawn, its precise determination by a specialist veterinarian be completed and the necessary therapeutic treatments initiated. Prescribing and use of medication is strictly regulated in almost all trout farming countries and is also usually carried out under the supervision of a veterinarian. In principle, only drugs that are approved for the disease to be treated may be used in EU countries. All these measures ensure that treatments are e ective and safe for the sh, the environment, and consumers. In order to be able to guarantee consumer safety, the prescribed waiting times between treatment and later harvesting for commercial use must be observed. Every single step in this package of measures must be meticulously documented. Obligations to provide evidence of the use of pharmaceuticals for edible sh result from the Drugs Act, the Food Hygiene Ordinance and the water law permit. Fish farmers must provide evidence of the purchase of veterinary prescription medicines (e.g. prescription, invoice or delivery note) and must record their use. At the same time, the veterinarian must also provide corresponding evidence of their prescriptions as a sort of cross-check.

Even RAS are not immune to diseases

e manufacture, use, and monitoring of veterinary medicinal products is regulated by the EU Code for Animal Medicines, which is supplemented by additional regulations in member states. However, in aquaculture there is a limited number of medicines that are speci cally approved for use in sh. e limited number of approved medicines for use in sh farming has been a cause for concern, with critics warning of a “therapy emergency” in the event of a disease outbreak. e use of disinfectants in aquaculture can be comparably complicated due to the limited number of approved disinfectants. Some active substances, such as malachite green, copper sulphate, or potassium permanganate, are no longer permitted in the EU. Even the use of lime for pond disinfection requires prior approval and must be used in prescribed concentrations to prevent it from entering other bodies of water.

Salmon trout, called “fjord trout” in Norway, spend part of their lives in the sea, like salmon, where they are exposed to marine pathogens and parasites.

Finally, a few words about the situation in recirculation systems, or RAS. As such systems are essentially isolated from the outside world, operators and the general public frequently assume that RAS are disease-resistant and safe. However, practice indicates that this is not always the case. In fact, circulatory systems have particularly favourable conditions for the emergence of illnesses and the multiplication of opportunistic microbes. High stocking densities, along with poor water quality, can promote the emergence of non-infectious illnesses.

Ammonia, nitrite, carbon dioxide, suspended solids, and ozone levels in circulation systems have already resulted in sh losses. Pathogen-related illnesses have also been observed in RAS rainbow trout. Bacterial (bacterial gill disease, furunculosis, bacterial kidney disease, n rot) and viral (IPN, VHS, IHN) infections are common. Occasional reports of parasites (Gyrodactylus, Chilodonella, Trichodina, Epistylis, Trichophrya, Ichthyophthirius) and fungi (Saprolegnia) have been recorded. e cause of these diseases is often the introduction of already infected stocking material and poor sta hygiene. Chemotherapy is extremely di cult in circulatory systems because there is always a risk of a ecting the bacteria in the bio lter. Consequently, e ective health management is critical to the success of these facilities and all other trout farms.

Manfred Klinkhardt

INFOFISH workshop to identify sharks and rays listed under CITES, Phuket, Thailand

e workshop was held in response to a request by the Department of Fisheries ailand. Its aim was to enable customs o cers and sheries o cers to identify parts of sharks and rays before permitting the trade of such goods at ai ports. About 50 participants from the Marine Fisheries Research and Development Division, and Fish Quarantine and Fishing Vessels Inspection Division, attended the workshop.

e training was led by Dr Haji Ahmad bin Ali, Southeast Asian Fisheries Development Center, Malaysia; and supported by Mr Tassapon Krajangdara and Mr Opas Chamason, Marine Fisheries Research and Development Division, Department of Fisheries, ailand. e topics included the taxonomy of sharks and rays recorded in ailand and the species listed in CITES Appendix I and Appendix II; the biology of sharks and rays recorded in ailand; products of sharks and rays listed in CITES found in ailand’s markets; and an identi cation guide to fresh and dried sharks and rays listed under CITES at sheries landing sites. In the practical session, participants were guided and trained on the external and

HS Codes for fisheries and aquaculture products

is publication, developed by the Food and Agriculture Organization of the United Nations (FAO), with the active support of the World Customs Organization (WCO), builds on the Harmonized System: Nomenclature 2022 edition. It presents all possible classi cations for sheries and aquaculture products by species, with a full description of each HS code, to facilitate its use within the sheries sector, including aquaculture. is publication does not modify the structure of the HS or modify species grouping, as it is an auxiliary tool to facilitate classi cation and enhance understanding of the HS system from the angle of sheries and aquaculture products.

is publication is divided into three sections: (1) the rst section presents all species which are directly referenced in the HS, with commodity codes for all possible classi cations of their products and treatments; (2) the second section lists all HS codes for sheries and aquaculture products with an exhaustive and comprehensive description of each code; and (3) the third section is a new section of the HS Handbook, where photos of the most internal morphology of fresh sharks and rays listed in CITES; photographic techniques for taxonomy used for important external parts of fresh sharks and rays listed in CITES; as well as on classi cation of sharks and rays listed in CITES according to order, family, genus, and species.

HS Codes for sheries and aquaculture products

commercially important species are shown. Each image contains relevant information and singularities of each species – scienti c name, FAO names, main characteristics, and distribution. e booklet can be freely downloaded from https://scanmail.trustwave.com/?c=766 1&d=8uOl5B8R8RcSqN6FUmlyndRnAz2abOS qO169uay3wA&u=https%3a%2f%2fwww%2efa o%2eorg%2fdocuments%2fcard%2fen%2fc%2f cc6347en