Health Challenges in Aquaculture Fiskerifaglig Forum Bergen, November 23-24, 2016 Edgar Brun
Infectious diseases The biggest killer of farmed fish
Global aquaculture 2014 More than 500 aquatic animal species need attention 18 million people are engaged in fish farming 94 % in Asia Produced 73.8 million tonnes (101 mill tonnes incl. aquatic plants) Estimated first-sale value of US$160.2 billion (168 bill incl aquatic plants) Aquaculture provided more fish for human consumption than capture fisheries Annual consumption of aquatic animal 20/kg per person (1-100 kg) FAO; Sofia report 2016
Global aquaculture Global growth of 6 % the last decade 2030-50: 9-10 billion people 2030: Global demand for seafood estimated to 261 million tonnes Governments have ambitious plans optimism Aquaculture seen as an efficient, CO2 friendly way of supplying people with essential nutrients Protein and minerals Investors and technology available Impatient - money More than 70 % low-scale production units
Economic impact of diseases Loss of > 6 billions US$ annually (a 2014-World Bank estimate) At local level loss of production (bankruptcy, jobs, income, food, infrastructure, hope) For the global segment of the industry
Health Challenges are associated to Trade Climate change Health management Governance and competence
Trade Fish are the most traded food commodity in international trade. Globalization is the driver of modern aquaculture Create opportunities and markets Intensification of production methods and the industrialization (modernization) of the sector. Transboundary movement Facilitate global spread of pathogen and diseases Making diseases a primary constraint to the culture of many aquatic species Increasing reliance on veterinary medicines around the globe to ensure successful and maximized production Intensification increase the risk of emerging diseases
Trade Secure safe trade Sanitary standards OIE and WTO acknowledge, implement, comply Documentation, surveillance and preparedness Recording and reporting Transparency Early detection (emerging diseases) Engagement from the farmers
Climate change Diseases at lower latitudes progress more rapidly and results in higher cumulative mortality (in particular at early stages of development and in shellfish) Tropical countries suffer proportionally greater losses in aquaculture during disease outbreaks and have less time to mitigate losses Environmental deterioration is likely to be more severe in tropics and interactions with climate change outcomes is bound to increase the frequency and risk of disease in tropics. Leung and Bates: Journal of Applied Ecology 2013, 50, 215 222
Diseases sensitive to climate change and intensification (reportable) Disease Epizootic Ulcerative Syndrome (EUS) Koi herpes virus disease (KHVD) Agent/species Fungus. 97 susceptible fish species. Freshwater and estuarine Virus. Carp species Viral Encephalopathy and Retinopathy (VER) White Spot Disease (WSD) Infectious myonecrosis White tail disease Virus 50 susceptible fish species (marine) Virus. Shrimp Virus. Shrimp Virus. Freshwater Prawn
Diseases sensitive to climate change and intensification(non-reportable) Disease/agent Streptococcus, Flavobacteria, Francisella, Aeromonas, protozoa, Streptococcus, Aeromonas, Edwardsiella, protoza, Shrimp AHPND Protozoans, flukes, crustaceans (Argulus, Lernaea) a.o. Zoonosis; Increased load of potential zoonotic bacteria, parasites, virus Species affected Tilapia Pangasius, diverse host range Shrimp - gene transfer turned a environmetal Vibrio bacteria into a shrimp pathogen Diverse host range of fish Any affecting 100 mill people
Climate change demand specific strategies to address geographical specific problems due to changes/fluctuations in eg. salinity, acidification, temperature, oxygen, may widen the geographical distribution and virulence of infectious diseases may cause immunosuppressive stress in host (increased susceptibility) may change mode of transmission, survival, virulence Knowledge on proper health management (epidemiology and ecology) to prevent and control infectious diseases in tropic aquaculture needed for active field implementation
Essential meaures to address climate change Africa (n=14) Asia (n=10) Europe (n=18) South America (n=19) Near east (n=5) North America (n=2) SW Pacific (n=2) Global (n=40) General prepardeness to manage risk 1,7 2,7 2,9 1,6 2,6 3,5 3,0 2,3 Farmers covered by assistanse scheme in case of disaster Aquaculture zoning to address all risks to production.,environment and society 2,3 1,9 1,1 1,3 2,0 0,0 1,5 1,2 2,6 3,0 2,6 2,4 3,0 3,5 4,0 2,5 Fish health management in place 2,7 3,5 4,0 3,2 3,2 4,5 3,5 3,3 The score for each statement ranges from 0 (measure non-existent) to 5 (measure in place, fully implemented and enforced at field-level nationwide (FAO)
Health management Biosecurity Prevention and containment systems that prevent the introduction of agents into and between the aquaculture operations and the environment Availability of vaccines Bacterial diseases? Viral diseases? For animals with poor ability for immune response (shellfish)? Antimicrobials
1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Tonnes 1000 tonnes 60 50 Antibacterial VMPs sold (tonnes) Biomass slaughtered farmed fish (1000 tonnes) 1600 1400 1200 40 1000 30 800 20 600 400 10 200 0 0
Use of antimicrobials in aquaculture Chronic diseases that cause reduced growth, low food conversion rate and poor survival thus leading to reduced production Epidemic diseases that can cause mass mortalities Failure of preventive therapy: good husbandry and vaccination does not always ensure or can act alone to prevent infections by pathogens that can only be resolved by the use of antimicrobials. New species in culture and new culture systems/management use of veterinary medicines in a lag phase between the identification and characterization of pathogens and the development of disease control procedures
Use of antimicrobials in aquaculture Antibiotic resistance Therapeutic concern Human concern Market Ecological concern Prudent use Improve knowledge on how and when to use antibiotics Effective policies, e.g. better regulations and enforcement; Capacity building at all levels of the aquaculture production chain
Governance and competence Strengthen legal framework, authority and infrastructure need to have in place appropriate and well-conceived legislation and regulations have trained manpower and infrastructure to enforce legislation and regulations (with appropriate penalties for violation) epidemiological and diagnostic knowledge of infectious diseases knowledge of national disease status Registration of antimicrobials, licencing of aquatic animal health professionals and others Public-private sector partnership should be promoted to share responsibility in the value chain.
Summing up some health challenges How can we balance the socio-economic drivers which propagate aquaculture with the need to prevent international disease spread? What new diseases will emerge from the changing host-parasite relationships associated with intensification and climate change? What mechanisms turn environmental bacteria into major pathogens? Can biotechnology effectively and acceptably control viral diseases of aquatic animals.. Incl. animals with rudimentary adaptive immune system? How can zoonotic fish parasites ( a.o.) be controlled? How can we imply control and prudent use of antibiotics in aquaculture? How can Norway use its health competence and help focus these challenges in a global perspective?
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