DISEASE MANAGEMENT IN AQUACULTURE FOR

A SUSTAINABLE FOOD PRODUCTION

by Dr. Lee Seong Wei

Dr. Hasnita Che Harun Mr. Shazani Sarijan Mdm. Wendy Wee

Faculty of Agro Based Industry Universiti Malaysia Kelantan

ASEAN Regional Conference on Food Security 2013, Penang

Presentation outline

Introduction to aquaculture

Commonly farmed species

Diseases in fish farming

Diseases in mollusk farming

Diseases in shrimp farming

Aquatic animal health management

Introduction to Aquaculture

Aquaculture is defined as farming of aquatic organism including fish, mollusks, crustaceans and aquatic plants.

Aquatic farming activity was recorded as early as 1100 B.C

where China is reported the first country that carried out common carp fish farming activity.

Other examples of early fish farming activity:

- pearl oyster farm in Japan - tilapia farm in Egypt - eels in Greeks and Roman - cultivation of oyster in Europe

Introduction to Aquaculture

Aquaculture industry is expanding rapidly due to the high demand for protein source.

World aquaculture production of food fish reached 62.7 million tonnes in 2011, up by 6.2% from 59 million tonnes in 2010.

The estimated value of farmed food fish is USD 130 billion. Aquaculture production in 2012 is estimated at around 66.5

million tonnes.

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Countries

World aquaculture producers of food fish in 2011

*Malaysia: 18th

Disease outbreak:

One of the major constraint in the development of aquaculture.

Significant economic loss.

Significant implication on food security.

Introduction to Aquaculture

COMMONLY FARMED SPECIES

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Fin fish Molluscs Crustaceans Others

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Group of species

World aquaculture production of food fish by main groups of species

Fin fish

Molluscs

Crustaceans

Others

Commonly Farmed Species

1) 103 species of fish

tilapia

tuna

cobia grouper

seabass

Commonly Farmed Species

2) 43 species of mollusk

mussel

oyster

green mussel

cockle

Commonly Farmed Species

3) 21 species of crustacean

lobster

giant freshwater

prawn

tiger prawn shrimp

Fish Disease Case Report

White spot disease (Ichthyophthirius)

-Indonesia (1932); Devastating Java barb, kissing gourami, common carp and giant gourami Buschkiel (1935), Sachlan (1952)

Lernaea cyprinacea -Indonesia (1983); 30% Of hatchery production in main hatchery centers of Java, northern Sumatra and northern Sulawesi affected. In Java, an estimated 1.48 billion fry were lost, USD 11.4 M economic loss Djajadiredja et al. (1983)

Diseases of cage-cultured grouper, snapper and seabass

-Malaysia; USD1.3 M in potential income—combined loss estimates of private sector and government farms

Seabass diseases -Thailand (1989); US$ 0.8 M economic loss ADB/NACA (1991)

Grouper diseases -Thailand (1989); USD 1.07 M economic loss ADB/NACA (1991) -Philippines (2002); 75% Reduction in household income; 19.4% increased debt Somga et al. (2002)

Koi herpes virus (KHV) -Indonesia USD 15 M economic loss -Japan USD 1.4 M economic loss

Ich (White Spot) Fish Disease - (Ichthyophthirius)

parasite that can infect most species of freshwater tropical fish and multiplies rapidly.

appearance of small, white, raised spots, similar to grains of salt,

on the skin. feeds on the skin and gills of fish, providing sites for infection by

other organisms, such as bacteria and fungus.

Lernaea cyprinacea, LC (Anchor worm)

LC is a copepod parasite that infects many freshwater fishes: common carp (Cyprinus carpio), goldfish (Carassius auratus), Japanese eel (Anguilla japonica) and oriental weatherfish (Misgurnus anguillicaudatus).

tissues adjacent to the head part of worm become

inflamed; susceptible to secondary infections of bacteria. this parasite is not infectious to human, it is harmless in

food hygiene.

Koi herpes virus (KHV)

viral disease of common carp Cyprinus carpio.

highly contagious and may cause up to 100% mortality.

display erratic behaviour, often

gathering at water inlets or points of oxygenation, show loss of balance, loss of mucus resulting in dry, rough patches, sloughing of mucus, and sunken eyes.

Agent: Koi Herpesvirus of the family Herpesviridae.

Mollusk Diseases Case Reports

Haplosporidium nelsoni (MSX)

-Chesapeake Bay, USA, since 1959; >90% Of oysters grown in the Bay Andrews (1968) -Canada, 2002; 80% Mortalities OIE Report (2002)

Mass mortalities associated with a viral disease

- Japan 1996–1997—Annual mortality in all of western regions >400 M oysters equivalent to 50% of oyster production in Japan. Miyazaki et al. (1999)

Perkinsus sp. - Korea 1997; Dramatic decrease in clam landings since 1993; clam landings in 1997 were 14,000 tonnes, 1/5 of the total landings in 1990 Park and Choi (2001)

Marteilia sydneyi - Australia; >90% Prevalence single most important pathogen of rock oyster US$ 30 million worth of production in NSW Australia Adlard and Weshe (2002), Kleeman and Adlard (2000)

Herpes type virus disease

-Australia; 80–90% Mortalities of larvae and spat in hatchery and natural beds Berthe (2002)

Withering syndrome of abalone

- California; Cumulative mortality over 99% OIE (2003a,b)

Haplosporidium nelsoni (MSX)

caused by the single-celled parasite Haplosporidium nelsoni.

valves slow to close when disturbed.

decreased rate of growth. no new shell growth. extensive fouling along the inside

peripheral left valve. juvenile oysters may have pale

digestive glands. oysters appear thin and watery. receding of the mantle. raised yellow-brown spots on

internal valve surfaces.

Marteilia sydneyi

the pale yellow-brown color of the digestive gland contrasts with the deep green of healthy oysters.

the body is greatly shrunken and tissues are translucent due to the complete resorption of the gonad.

kill up to 80% of infected oysters with up to 100% prevalence.

Withering syndrome of abalone

is caused by the bacterium Candidatus Xenohaliotis californiensis.

Lethal disease: lethargy, retracted visceral tissues, atrophy of the foot muscle.

Body mass relative to shell size is smaller than normal.

discoloured (pale) and weakened abalone.

the soft tissues were atrophied and non-responsive to stimuli.

Perkinsus sp.

caused by parasitic protozoan in some commercially important mollusks including oysters, clams, abalones and scallops.

frequently induces the formation of

white or light brown nodules on the gills, foot, gut, digestive gland, kidney, gonad and mantle.

massive concentration of haemocytes

around the infected tissues. often results in mass mortalities and

commercial loss.

Diseases in Shrimp Farming

Shrimp Diseases Case Reports

Yellow Head Disease (YHD)

-Thailand (1992); USD 30.6 M economic loss (Nash et al., 1995)

White Spot Disease (WSD)

-Malaysia (1995); USD 25 M economic loss (Yang et al., 2001) -Bangladesh (1996); USD 10 M economic loss (Rahman, 2001) -Ecuador (1999); USD 280 economic loss (Alday de Graindorge and Griffith, 2001) -Honduras (1999); 13% Reduction in labour force (Corrales, 2001) -Nicaragua (1999); 5–10% Survival rate (Drazba, 2001) -Panama (1999); US$ 40 M worth of export loss; closure of major hatcheries; loss of jobs (5000 people directly and indirectly involved in the industry) (Morales et al., 2001)

YHD + WSD -Vietnam (1993); USD 100 M economic loss (Khoa et al. 2001) - Thailand (1994); USD 650 economic loss; 12% production decline from 250,000 tons in 1994 to 220,000 tons in 1995; shrimp losses for 1997 reached nearly 50% of total farm output value.

Taura Syndrome Virus (TSV)

-Panama (1996); Outbreak resulted to 30% reduction in production Morales et al. (2001) -Costa Rica (1996); caused reduction in survival rate from 65 to 15%. Vargas (2001)

Early Mortality Syndrome (EMS)

- Asia (2011-13); White Leg Shrimp Culture; Devastating White Leg Shrimp Industry.

WHITE SPOT DISEASE

show rapid reduction in food consumption.

lethargy. loose cuticle with white

spots (which represent abnormal deposits of calcium salts by the cuticular epidermis) that are most apparent on the inside surface of the carapace.

agent: baculovirus 0.5 – 2.0 mm

WSD

0.5 – 2.0 mm WSD

YELLOW HEAD DISEASE (YHD)

normal YHD

pale body. yellowish swollen

cephalothorax & hepatopancreas. whitish-yellowish-brownish gills presumptive diagnosis can be

made on basis of pond history, clinical signs, gross changes & histopathology.

agent: not yet describe.

TAURA SYNDROME VIRUS

pale red body surface and appendages.

tail fan and pleopods particularly red.

shell soft and gut empty. death usually at moulting. multiple irregularly shaped and

randomly distributed melanised cuticular lesion.

agent: baculovirus.

Aquatic Animal Health Management

Disease

Aquatic Animal Health Management

Improvement of health: feed quality

Stress prevention: handling, transport and stocking density

Stimulation of defense system: immunostimulation, vaccination, natural products (horseshoe crab, Limulus polyphemus and marine seaweed)

Selective breeding for disease resistance

Host

Good hygiene: disinfection, quarantine

Water quality: bio-augmentation, water treatment

Environment

Virus: Vaccination

Prevent or control viral pathogen spread

Pathogen

Bacteria:

Specific killing of pathogenic bacteria: phage therapy (Bacteriophages), specific antibacterial compounds, antibiotics

Growth inhibition

Inhibit the virulence gene expression and virulence gene regulation (quorum sensing)

Pathogen

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