final Flashcards
what is the water quality for carp and trout?
carp: 15-30oC
truth 2-18C
ammonia
acute poisoning: 0.8-2 = neurological signs
chronic poisoning: 0.2 = poor growth, severe gill damage
which fish is very sensitive to hypoxia
pikeperch
why can hypoxia occur?
summer: increase of algae,
winter: ince - cessation of photosynthesis
due to transportation: increase in swimming activity
cage: temperature/water inversion
clinical signs of hypoxia
lighter in colour
death with opercula flared and mouth agape
treatment + prevention for hypoxia
increase aeration, reduce feeding, reduce fish density, prevention of algal bloom
prevention:
fins
folds of skin supoprted by bony rays
paired fins: pectoral and pelvic
unpaired: dorsal, caudal, anal and adipose
- adipose fin = “sensory” organ
types: spiny (one bone), soft (small segments)
layers of skin
epidermis - upper mayer - mucous cells + not keratinised
dermis - lower layer - scale
1. stratum spongiosum - loose CT, capillaries and pigement cells
2. stratum compactum -dense CT
- scales inside dermis
= siluridae = lack scales completely
= reduced in eels
scales
placoid (sharks and rays)
ganoid (sturgeon)
cosmic (ancient fish)
elasmoid (teleosts) cycloid (without small projection, Salmond, carp) and ctenoid (pikeperch)
- calcified, flexible plates
- siluridae lack scale
- reduced in eel
pigment cells/ chromatophores
melanophores (dark pigment, melanin)
erythropores (red)
xanthopores (yellow)
iridophores
colour changes: physiological and morphological
types of muscle
cardiac
smooth
skeletal: head, trunk, tail and fin
axial: organised in muscle blocked/myomere, which are further separated by myosepta
gills
gill lamellae, gill arches
opercular cavity = operculum (bracnhiostegal membrane), gill arches (rakers)
4 pairs of gill arches
on each Gill arch:
- outer surface = 2 rows of gill filaments (primary lamellae)
- on inner surface = gill rakers
primary lamellae = supported by cartlage
secondary = gaseous exchange
heart
sinus venosus
atrium
ventricle
conus arteriosus
bulbs arteriosus
oral cavity
up to last pair of gill arches
who lacks a stomach
cyprinidae
liver
compact organ or split into lobes that interdigitate with intestine
- in carp = hepatopancreas
- hepatocytes = polygonal cells, containing central spherical nucleus, containing different amounts of lipid + glycogen
pancreas
surface of intestine (between pyloric caeca), in liver (hepatopancreas) or spleen
kidneys
retroperitoneally
two, mostly fused organs
cranial (head) and posterior kidney
hematopoetic and excretory role
osmoregulation
swim bladder
hydrostatic organ that can be filled or emptied to regulate buoyancy
physostomes
physicists (closed)
- absent in many bottom living species nad some fast swimming
- carp = 2 chambers separaed by diaphragm
1. tunica interna (transparent) - epithelial layer; overlying muscularis mucosa and submucosa of loose CT
2. tunica externa - fibrous layer’ with muscle and elastic CT
reproductive system
serranidae, sparidae = hermaphroditis
external fertilisation
gynogenesis
development from an ovum stimulated to divide by penetration from a sperm which doesn’t contribute genes
copulation
resulting in either discharge of fertilised eggs or viviparous release of young fish
sexual maturation
warm water: 3-5years
cold: 2-4 years
spawning period each year
exception: eel, salmon
which are predatory fish?
European catfish, pikeperch and pike
natural spawning of (common) carp
- sexual maturation (F 3-5yr, M 4-6 yr)
- spawns: may- June (17-20C)
- eggs: sticky
- spawning: once per year
when you catch the brood stock, you do the sex determination
- male are elongated
- females are more rounded in shape, big and soft stomach
- caudal urogenital papilla - female = red, males = see a bit of milk
conditioning and hormone treatment
- salt bath
- anaesthetisation (MS 222, benzocaine)
- weight
- tag
- hormone application (CPE, GnRH)
= female is 2 injection, 1st dose is 10% of total dose 24hrs after, inject 2nd dose is 90% total dose
= male - 1 dose, injected at same time as 2nd dose for females
= lateral musculature, long and short - females - stitching of genital papillae - otherwise after second dose, female might release the eggs
carp: stripping and fertilisation
- harvesting eggs and milt (dry method)
= when harvest milk, put in fridge for 5 days
= 1 female and milk of 2 males - fertilisation solution (urea, NaCl) mix it all gently (1h, otherwise will stick together)
- stickiness removal (tannin solution, tannin removes embryo if left in too long)
- sperm = motile in contact with water 2-3 minutes
egg incubating and larvae rearing
- zuger/McDonald jars
- 3-3.5 days at 23oC after hatched -> transported to larvae containers
- larvae hatching lasts 3-4 days at 23oC (no feeding)
larvae transportation and stocking
- transportation in PVC bags pressurised with oxygen
- temperature adaption
- 0.5-2ha ponds
- leave 1 month - mortality can go up to 70%
nurses pond prep
- everything needs to be completely dry
- disc ploughing
- liming (500-1500kg/ha)
- fertilisiing
- water intake - plankton sieve
- insecticide treatment
larvae/early fry feeding
- starter feed
- hard “dough” - fish meal, poultry meal, soybean meal…
- min 45% raw protein
- feed 2x day
- survival rate 20-40%
advanced fry harvesting
- 4 - 6 weeks post stocking
- 2-5g fry
- restocking in 5-20ha pond
- 25000-40000 fry/ha
advanced fry feeding
- extruded pellets
- size: 2mm
- min 40% raw protein
- ground cereals
- feeding: once per day
one- Summer fry (c1) (1m- 1yr)
- overwintering in some ponds or autumn harvesting and stocking in overwintering ponds
- survival rate: 50%
- size 30-80g
- biomass 800-900kg/ha
feeding
- extruded pellets
- size: 4-6mm
- min 30% raw protein
- cereal grain
- feeding: once per day
pelagic
liver and feed away from the bottom in open water
- coastal (herring, sardine)
- oceanic (tuna)
demersal
bottom feeders
- benthic (flatfish) or benthopelagic (most species)
viral disease of warm water fish
- spring viraemia of carp
- carp pox
- koi herpes virus disease
- koi sleepy disease
carp pox (cause, signs, mortality, effects)
- cyprinid herpesvirus 1
- common carp
- benign, hyperplastic, papillomatous growths in skin
- mortality can be high in juvenilles
- diseases outbreak 15C
culture conditions for salmons
- pH 6.5-8
- dissolved oxygen > 6mg/L
- incubation of eggs 4-12oC
- ingrowing stage 10-15C
broomstick management for salmons
- rainbow trout
= male 2-4, female 3-6
= feeding at 1-2% biomass, stop at 14 days prior to spawning
-trout
= males lower jaw is longer than upper and bent at the end
= females low jaw is shorter - salmons should be anaesthesia before stripping
= MS222, sigma
= can’t leave in too long as it’s also used for euthanasia
stripping and fertilisation of salmons
- (dry methods)- dry bowl, stripping of eggs, stripping of milt
- gentle mixing, adding water
- water activates the spermatozoa
- 3 males for 1 female
- Salmon eggs aren’t sticky
- milt motility: brown trout (25s), rainbow (40s)
Russian method = ovarial fluid is remove (sieve), brown trout 75-80% fertilisation rate
German method = no removal of ovarian fluid - rainbow trout - 95%
egg hardening - eggs absorb water and grow in size. micropyle closes
disinfection of salmonid eggs
- two possible times:
1. before incubation but after egg hardening
2. at eyed stage - organic iodine compounds
- should completed within 10hrs from fertilisation
type of incubation of salmon eggs
vertical tray
= saves space (water goes through all of them overflows)
california tray
= metal
upwelling incubation
= glass or plastic
= water goes from bottom to top and overflows. cannot remove the dead eggs because they’re constantly moving
incubation of salmonid eggs
- at 5oC
- rainbow = shortest incubation period (400oD)(80days)
- brown = (500oD)(100days)
- need to remove dead eggs as it’s a source of growth of fungi
- can transport the eggs when in eyed stage
- removal of dead and unfertilised eggs - soaking in 8% NaCl, dead eggs will float to top
incubation of yolk-sac larvae in baskets (salmon)
- rainbow 150-200oD or 2-3 weeks at 10oC, Atlantic 290oD
- larvae rest on their sides - sensitive phase
- after larvae absorb 2/3 of a yolk sac, swims to the surface to inflate swim bladder when ready
fry rearing of salmon
- transfer of fry to fibreglass, metal or concrete tanks
- indoors - fry are sensitive to light
- fry rearing takes 6-8weeks (up to 90days post hatching) –> juveniles 3-5cm
- fed using pelleted feed
feeding salmon fry
1st = manual feeding with starter feed
- 12 times/day
- 20-22hr period with 2-4 hr darkness
- min 55% protein
- Ca 8% body weight per day
later = automaticallyc feeders can be used
feeding salmon juvenilles
- manual/automatic feeding (6-8time/day)
- need to do regular sorting of the pellet - increases feeding efficiency
- market size (250-300g)
grow out in floating sea cage
rainbow trout
- transfer of juveniles at 70-100g weight
- requires acclimatisation by gradually increasing water salinity
- double growth rate in fresh water
atlantic trout
- smolts at 35-50g
- 4kg after 10-15months
infectious with motile aeromonas - infection with pseudomonas
- aeromonas hydrophilic, pseudomonas anguiliseptica (negative)
- fresh water and marine fish
- mostly as secondary invaders after skin injury
- haemorrhagic septicaemia
- diagnose: isolation from kidney/spleen
- treatment: antimicrobial therapy
tenacibaculosis (marine columnar)
- marine fish
- stress after transfer to cage, overstocking, sunburn
- localised lesion in gills (necrosis), skin (ulcers), fins (rot)
- medicated feed (antimicrobials), bath treatment with hydrogen peroxide or formaline
pasteurellosis - pseudotuberculosis
- gram negative
- marine fish
- factors: European sea bass, high temp, juvenilles
- horizontal
- entry: skin, intestie
- peracute: fry, mortality up to 100%
- subacute: older, multiple nodular white foci in spells, kidney, liver and skeletal muscle
- diagnose: general purpose media with NaCl,marine agar
icthyophthirius multifilis
- aetiological agent of white spot disease or itch
- all freshwater fish
- white spots on skin and gills, increase in mucus production, erosion of epithelia
- trophont (feeding stage) > tomont > cysts with tomites > theronts (free swimming pear shaped infecting)
- 24oC - 7 days
- treatment; immersion: copper sulphate, potassium permanganate, salt, formalin
myxozoa
- hosts: fish and annelids
- fish shed myxospore into water > ingested by annelids > enter intestinal epithelium > actniospore develop > invade fish through skin and gills/gut
myxobolus
- trout, salmon
- whirling disease
- Brain and cartialge
- darkening of caudal region, skeletal deformities
haerospora dykovae
- swim bladder and kidney
- young
- mortality up to 100%
- common carp
- through gills, migrate through to swim bladder
- swim bladder inflammation
- signs: reddening, letahrgy, distended abdomen
- treatment: oxytetraycline
arthropoda
- direct transmission
- ectoparasites, feeed on blood and tissue
- attach to the fish surface with pair of round suckers
- skin irritation and behavioural signs
- hyperplasia of epithelium and increased mucus production
erathothoa bestrides (buccal parasite)
marine fish and direct transmission
where can you do venipuncture?
haemal canal
muscle
trunk and tail muscle
- separated by vertebral columns
- CT septum (epaxial + hypoxia muscle)
- organised in muscle blocks or myomere (Z or W)
- myomeres are separated by myosepta
- myosepta ossifies = myoinsepta muscular
type of muscle fibre
red “slow” fibre
- highly vascularise -> red aerobic muscle used for long term sustatined swimming and moderate speed swimming
white “fast”
- poor vasculariation > white anaerobic muslc eused for bursts and strong swimming activiyty
marteilosis (entry, why, sampling)
parasite proliferates within epithelium of GIT
- when sea temp >17oC
- sampling and diagnostic same as bonamiosis
what does marteilosis affect?
European flat oyster and mussels
pacific oyster resistent to infection
signs of marteilosis
pale digestive gland
flesh-thin and watery
mantle retraction
stunted growth, gaping, death (50-90% oysters, <40% mussels)
cause of marteilosis and vector
cause; marteilia refrains, intracellular parasites
vector: planktonic crustaceans
bonamiosis
- paraiste proliferates mainly in haemocytes
- most common in later winter and spring
- older oysters, infection is lethal, usually withouth sympto
cause of bonamiosis
bonamia ostrea… parasites
what does bonamiosis affect
European flat oyster
pacific oyster is resistant to infection but can act as carrier/reservoir
sampling of bonamiosis
- PCR - gaping/freshly dead individuals
- for histopath - only live oysters, shipped on ice
- time of sampling - once a year when prevalence is at max
- lab: stained imprinting, histology, PCR
platyhelminths
cestode
monogena
trematoda
diplostomum spathaceum
monogena
- platyhelminths
- direct life cycle (no intermediate host)
- both male and female
- oviparous, viviparous, host specific, ectoparasites
Trematoda - diagenea
- platyhelmith
- indirect (intermediate host)
- hermaphrodite, oviparous
diplostomum spathaceum (eye fluke)
- platyhelminth
- fresh water fish, free metaceracariae in eye, cataracts, blindness
cestode
- platyhelminth
- indirect life cycle
- hermaphoridte
- oviparous
viral hemorrhagic septicaemia (VHS) (mortality, transmission, control)
- mortality in fry up to 100%
- transmission: horizontal
control: official health, disinfection… - typical occur when temperatures are fluctuating and generally below 14C
cause of VHS and vector
cause: rhabdoviridae
vector: piscivorous birds
VHS effects
rainbow and brown trout
- all age groups susceptible
signs of VHS
acute: lethargy, dark skin, haemorrhage (in skeletal muscles), marked distension of abdomen
chronic: dark skin colour, swollen eyes, mortality
nervous: abnormal swimming behaviour, mortality is low
haemorrhagic anaemia
spring viraemia of carp (transmission, mortality)
- transmission: horizontal
- mortality up to 70%
- disease outbreak 11-17C
spring viraemia of carp cause and vector
cause: rhabdoviridae, genus vesiculovirus
- vector: parasites
host for spring viraemia
common carp
signs of spring viraemia of carp
hemorrhagic anaemia, anaemia, enteritis, peritonitis
koi herpes virus (KHV) (transmission, mortality/morbitidy)
- disease outbreak: 16-25C
- morbidity up to 100%
- mortality up to 90-100%
- transmission: horizontal
KHV cause and vector
cause: cyprinid herpes virus 3
vector: piscivorous birds, parasites, other fish species
KHV affects
common carp and koi carp
signs of KHV
gill necrosis
anointhalmia (sunken eyes)
infectious haematopoeitc necrosis (IHN) (mortality and transmission)
- mortality in fry and fingerlings
- transmission: H + V
cause and vector of IHN
cause: rhabdoviridae, novirhabdovirus
vector: piscivorous birds, parasites
who does IHN effect
mostly young salmonids
but all age groups are suspectible
- disease outbreaks typically occur at 10-12C
signs of IHN
- hemorrhagic anaemia
- fecal cast (mucosal sloughing of gastro wall)
- lethargy, abnormal swimming behaviour
- ascites, exopthlamia, stomach and intestine contain yellow whitish fluid
infectious pancreatic necrosis (IPN) (mortality, transmission)
- mortality 10-90%
- transmission: H + V
IPN caused by
birnaviridae - genus aquabirnavirus
10C
IPN affects
salmons
acute contagiouss disease of young salmonids (eel)
signs of IPN
abnormal swimming, dark skin, distended abdomen
haemorrhage in ventral areas, edema and swelling
faecal casts
viral encephalopathy and retinopathy (transmission, mortality)
- transmission: V + H
- higher mortality and earlier appearance of disease
- in larvae 100%, older 20-50%
- 22C summer
what causes viral encephalopathy and retinopathy
nodaviridae, genus betanodavirus
who does viral encephalopathy and retinopathy affect
peracute to acute - younger marine
mainly larval and juvenilles
signs of viral encephalopathy and retinopathy
- vaculoating lesions of CNS and retina
- dark pigmentation, loss of appetite, erratic swimming, inflation of swim bladder
furunculosis (predisposition, transmission, entry)
- sudden temp change (12-15C) + stress
- horizontal + Vertical
- entry: skin, gills, gut –> septicaemia
cause of furunculosis
gram negative bacteria - aeromonas salmonicidia ssp.
who does furunculosis affect
salmon - juvenilles
signs of furunculosis
juvenilles (peracute)
- rapid death, w/o signs, darker skin (exophthalmia)
growing fish (acute)
- mortality up to 70%, hemorrhagic (fin + internal)
older (subacute/chronic)
- furuncles (liquefactive, haemorrhagic “boil” in superficial muscle)
furunculosis: treat, control and sample
sample: isolation of pathogen from kidney on TSA at 22oC
treat: medicated feed (oxytetracycline, florfenicol)
control: vaccinaition, good husbandry, disinfection of fertilised eggs
enteric red-mouth disease/yersiniosis cause:
gram negative bacteria - yersinia ruckeri
yersiniosis affects
salmonids
juvenilles more suscpetible
yersiniosis signs
acute/chornic septicaemia disease
- haemorrhagic septicaemia, haemorrhages in and around mouth at fin bases
- empty instesinte, filled with gases
- intestinal haemorrhage, petechiae on serosa membranes
- swollen kidneys and splenomegaly
yersisonosis: sample, treatment and control
sample: isolation of pathogen from kidney on tryptic soy agar
treatment: initiate at 1st signs of mortality, medicated feed and beta glucan
prevention+ control: vaccination, maintaining good husbandry, disinfection of fertilised eggs and reduce stocking density
yersisosis (conditions, transmission, entry, mortality)
- sudden water change (8-16C), stress
- horizontal (faeces), vertical and reservoir
- entry: intestines and gills
- acute/chronic = 50-70% mortality, endemic 10-15% mortality
bacterial coldwater disease/ rainbow trout fry syndrome (condition, transmission)
- low temp, <10oC, poor water quality
- horizontal (diseased fish, carriers), vertical (eggs)
rainbow trout fry syndrome cause
gram negative bacteria - flavobacterium psychrophilum)
who is affected by rainbow trout fry syndrome
salmons
younger
signs of rainbow trout fry syndrome
- acute septicaemia, mortality up to 50%
- peduncle: older, sepsis on localisation skin
- 1st sign = caudal/peduncle fin erosion, increased lethargy, exophahtlamia, abdomen swelling
- path: pale gill, ascites, splenomegaly, pale liver (internal pathology predominates)
- 1st sign (peduncle) = damaged fin tip, rough appearance on skin, ulcers surrounded by yellow pigmented bacterial colonies (external pathology predominates)
rainbow trout fry syndrome (sample, treatment, control)
sample: isolation from kidney/spleen on media 15oC
treatment: medicated feed (antibiotics)
control: disinfection, reduce density, remove fish, no vaccine available
carp erythrodermatitis (entry, transmission)
- enters through damaged skin (skin injury, spawning, summer)
- horizontal
- bacterium penetrates through skin erosions and multiples locally, inflammatory process developed so necrosis occurs. osmotic imbalance due to breakdown of skin integrity
carp erythrodermatitis cause:
gram negative - aeromonas salmonicidia
signs of carp erythrodermatitis
primary sign is ulcer = spherical, red necrotic centres and white peripheries
- ascites, secondary infections, healing of ulcer leaves dark pigmented scar
sample and control of carp erythrodermatitis
sample: clinical, blood agar
control: prevent access of birds
columnar - saddle back disease (conditions, transmission)
- poor water quality, high temp and stress
- horizontal
columnaris cause
gram negative bacteria - flavobacterium columnare
who does columnaris affeect
all fresh water fish
young
signs of columnaris
- localised infection but may progress to septicaemia
- skin: increase in mucus on head + upper body, circular areas of greyish growht
- fins: lesions extend from distal to base, encircling fish (looks like saddle)
- gills: whitish spots on filament tips
- lesions covered with yellowish white mucous
sample and prevention of columnaris
sample: skin + gill swab, isolation on special media
- maintain good husbandry
listenilosis (conditions, transmission, entry)
- sudden temp change and stress
- horizontal
- entry: intestine, damaged skin
cause of listenilosis
gram negative bacteria - listonella anguillarum76
who does listonella affect
marine fish (trout and eel)
signs of listontella
peracute: rapid death, no signs, cardiac myopathy
acute: haemorrhage, pale liver, enlarged spleen
chronic: ulcers, corneal opacity, ulceration + blindess
sample, treatment and control of listonella
sample: isolate from spleen/kidneys+ susceptibility testing
treatment: based on results + resistance
control: vaccination, reduce density and probiotics
what species are included in polyculture
common carp
tench
Prussian carp
grass carp
bighead carp silver carp
european catfish
pikeperch
pike
spring viraemia of carp temperature
11-17C
carp pox temperature
15C
koi herpes virus temperature
16-25C
VHS temperature
<14C
infectious haemopoetic necrosis temperature
10-12C
infection pancreatic necrosis temperature
around 10C
viral encephalopathy and retinopathy temperature
> 22C
furunculosis temperature
12-15C
enteric red mouth/yersinosis temperature
18C
rainbow trout fry syndrome temperature
<10C
columnaries temperature
high temperatures
listonella temperature
high temperatures
pasteurellosis temperature
high temp
18-20C
