COA424: Aquaculture Exam 1

Biochemical Oxygen Demand

measrument of the rate at which microbes degrade organic matter using oxygen

amount of O2 that would be consumed if all the organic material were oxided by microbes

Meausring BOD

• Use oxygen meter to measure one sample 

• Seal the other and isolate in the dark for 5 days, and remeasure

• BOD: 1st reading- 2nd readings

Chemical Oxygen Demand

• Oxygen used in biological and non-biological oxidation of all organic material in water

• Sample oxidized w/ acid and heat. Amunt of O2 required measured 

• Always higher than BOD

more oxidizable (biological treatable) material is

greater ratio BOD:COD means

Phosphates

• aturally occurs in rocks and minerals, mineralized, organic P (aquaculture) 

  • Water soluble

  • Plants uptake 

Redfield ratio

106:16:1

C:N:P

Nitrogen Cycle

Decompostion by fungi and bacteria → NH2→ Oxdiation by Nitrosomonas Bacteria→ NO2→ oxidation by Nitrobacter bacteria→ NO3→ incopration into plant protein OR reduction by anaerobic detrinyfing bacteria (N2)

nitrosomanas

bacteria that oxidizeds NH3 to NO2

nitrobacter

bacteria that oxidizes NO2 to NO3

Total Ammonia Nitrogen (TAN)

Meausre of unionized-ammonia (NH3) and ammonium levels in water

→ ratio of ammonia and aommonium varies in equilibirum

→ determined by pH and water levels

ph and temp

TAN increases with increasing ______

Turbidity

causes light to be scattered or absorbed rather than transmitted through water in a straight line

caused by suspended materials in the water: soil partickles, plankton, and organic detritus

Total suspended solids processing

1. Filtered through a glass fiber filter

2. Dried and weighted

3. Settle by gravity 

4. Determined total amount og suspended soils in mg/l of sample 

Total Dissolved solids

1. Solids that pass through a filer with a pore size of 2.0 microm or smaller

2. Said to be nonfitlerable (?) 

3. Steps of processing: 

   1. Liquid dried

• Residue weighed 

  1. Calculated as mg/l

Volatile Suspended Solids

1. Steps of processing: 

   1. Heat to 550 degrees 

2. Rough approx. of the amount of organic matter present in the solid fraction of waste water, activated by sludge and industrial wastes

>500 mV

redox level that is toxic to life

300mV

optimum levels of redox potential

oxio-reduction potential

measure of the ability to lose electrons or gain electrons

high reading: higher availability of oxidizing agents in the water

high oxdation levels increases bio-degradability and reduces toxicity

Tolerance range

critical thermal max and min

temp is increases progressivley to determine lealth end point

select species for outdoor production system to avoid losses

determining thermal min and max

Optimum tempetaruere

temperature determination involves comparsion to zootechnical parameters at different temperatures

ex: growth rate, food conervsion index, bioenergetics modeling

Preferendum

can be assessed based on field sampling in wild or experimentally in selection trails

isomatic

300-400 mosm or salinity of 12-15: associated with optimal growth paramters

damages GILLS and other tissues

at low concentrations, NH3

damages nervous systems and death

at high concentrations of NH3

1 ppm

toxic concentration s of NH3 in sw

Gill lesions 

Edema in the skeletal muscles 

Affects respiration 

nitrate toxicity

Freshwater

nitire is toxic for fish living in this type of environment

2-3 ppm

oxygen levels that result in mortality events

bubble gas disease

supersaturaiton of O2 and N2 resutls in bubbles in eyes, gills, skin, and cause death

> 80%

comfort levels of O2 for most fish

Chloramine

saturation of this compound to tap water to kill microorganisms, can persist for days or weeks

removal is done through a blaster

causes Necrosis to gills

metals

this has toxic effects to inverts at levels as low as .02 ppm

supersatruation of nitrogen

occurs with rapid cahnges in temperature and saturation, entrainment of air through leaking joints or pump seals or excess nitrogen source in water

alkalinity

the buffering capacity of a liquid, resistane to pH changes

Concentration of all bases in seawater that can ACCEPT a proton

usually bicarbonate, carbonate, or borate

Hardness

carbonate alkalinity alone (Ca and Mg) moslty used in FW studies

Alkanility measurment

mesured by titration to a known end point

20mg/L

minimum alkalinity

Gravity Aeration

• Water is cascaded over screens, rocks, beads to break it up and increases surface area for exchange 

surface active aeration

Agitate culture water up into the air

diffuser aeration (active)

Bubbles air through water which forms airstones 

ex:venturi device, u-tube

u-tube

device that ibjects air on the downlfow to increase contact

Venturi device

device that restricts flow, increases speed, and decreases psrrue to get air stuck and increase exhange rates

Downflow Contactor

Device used for aeration

• Water and O2 are located in the top after injection 

• Water velocity decreases with increasing diameter

• Downward velocity then equals buoyancy of the bubbles, which increases the SA for exchange and stays suspended in the water 

• Results in 95-100% transfer

Biofloc system

type of intensive closed system

that mamanges waste differently than the reciriculating system

uses microbial biotechnology to increase edidcy and utlization of fish feeds

uptake nitrogen by adding carbon sources

Advantages of closed systems

• Complete control over environment 

• Biosecure

• High density: lots of animals, space efficiency 

• Decoupled from water source: can implement this strategy anywhere 

• Limited discharge rates

Disadvantages of closed systems

• High maintenance, and labor costs

• Complex filtration and management 

• Equipment 

• The high density of fish: no room for error and no buffer

• Decoupled from water source: no room for error 

4 main issues in recirculation aquaculture system

• Oxygen 

• Solid waste

• Nitrogenous waste

• Dissolved organics

.5

1 kg of feed requires ____ kg of O2

Packaged Column

techqniue to degas CO2

water is cascaded over screen and air is pulled up and outgasses

pulls out O2 as well, may need to increase O2

1.38 g

____ about of Co2 produced for every g of O2 consumed

Settling Tank

technique used to mechanically filter out solids

• Use gravity, and decrease flow as heavy stuff settles 

  • Coagulation of particles does increase efficiency 

• Catches particles >100 microns 

• Take significant space

Centrifugation

technqiue to mechanically filter out solids

• Spins water, more dnes particles settle faster

• Continuous flow centrifuge or hydrocyclone 

• Increased flow is required, usually pumped 

• Catches particles >75 microns 

Cartidge filters

• Useful for small systems 

• Not as efficient to big systems, must be constantly replaced

• Prone to fouling 

Rotary drum filters

type of mechanical filtration of solids

• self-cleaning 

• Big, mechanical, use lots of water

• Choose mesh sizes up to 50 micro m 

• Common in raceway and pond systems

Particle filter

Mechanical method of solid filtration

• Uses sand particles to trap solids 

• Propeller-washed bed filters

• Water is forced through the bed of particles, where the solid are trapped 

• Cleaning occurs when flow is required 

• >25 microns 

Foam Fractionation

Type of mechanical filtiraiton of solid particles

• Air is injected into the water to form tiny bubbles 

• Bubbles create an air-water interface that traps contaminants

• Hydrophobic molecules are attracted to air molecules 

• Removes dissolved susbtances and fine particles (<25 microm) 

4.75g, 7.14g

1 g of waste water requires ___ of O2 and _________ of bicarbonate

Submerged

type of biofliter

made out of gravel, shells, palstic

suitable for systems with low biomass

water is puleld through it for filitration, but O2 limited

Trickle

Type of biofilter

• Suspended media in air to solve O2 issue 

• Water is trickled by gravity 

drum

type of biofitler

• moves media throught he water

• contact occurs on the surface for aeration

Moving bed bioreactors

type of biofilters

utilizes floating plastic carriers (media) within the aeration tank to increase the microorganism available to treat wastewater

media provides increased SA for microorganisms to gorw in aeration tanks

media is cosntnatly agitated by bubbles for aeration systmes that adds O2 at the bottom

Centrifugal ual pump

impeller that slings water out of the center, remaining vacuum slings more water in, increasing KINETIC FORCE

auger (corkscrew pumps)

type of pump that picks up water at the bottom of the system

Liquid rings

pump that ceates a ring of liquid around teh side of a pump, which creates a suction area in the middle

water flow produces a vacuum

choke it

to convert conetrigual pumps to head pressure and thus produce potnetial energy, you have to

Airlift

type of pump with no moving parts and a low head (15m lift)

air is injected into a column of water> bubbles move up and moves water out w/ increased bubbles

Continous weak sunction

L:D important

UV Light

disingection tech.

disrupts unsaturated bonds in DNA

requires space

dose depends on the goal, noramly 250nm is used

O3

Disinfect tech.

pass air through high voltage to create O3, bubbles through water like a protein skimmer

powerful oxidizer

adds O3 to the system

dangerous: corrosive and degrades elastic

white spot syndrome

type of dsDNA 300kbo

enveloped virion

causes 80-100% morality within 10 days

impacts shrimp populations espeically in pond systems

impacts the pancreas

alwasy a revision for animals in a pond to infect

first emerged in 1992 in taiwan

Taura Syndrome Vrius

type of ssrna virsus

non eveloped viron

paneid shrimp pathogen

gross signs: melanated spots on carapace

histological signs: disrupts digestive eptihelial systems

emerged in South America in early 90s

Infectious Salmon Anemia Virus

type of ssRNA noneveloped viron

apart of family Orthomyxovirus

consists of 8 RNA sequeuces that will coe apart and resemble, generating a DIFFERENT virus

develops slowly (incubation period of 2-4 weeks)

significant problem anywhere that grows atlatnic salmon

gross signs:

systematic virus, hemoragging on skin, anemia, pale gills, enlarged liver and spleen, hemorages in visceral fat

V.parahaemolytics

type of bacterial pathogen

symptoms:

• Acute Heptopancreatic Necorsis syndrome

• Shrimp early mortaility syndrom

• disrupts pancreatic function

V. anguillarium

type of bacteria that affects close to 50 species of fresh and saltwater fish

major obstacle to salmoid marine culture

mycobacterium marinum

• gram positive,

• Slow growing 

• CHRONIC fish Diesease 

• Non-motile 

• Symptoms: 

  • Weight loss 

  • Open ulcers 

  • Distended Abdomen 

  • Anorexia

Perkinsus marinus: dermo

• Host: eastern oyster, Crossotrea viriginca 

• Depends on: temperature, salinity 

  • Temps >20 C and salinity >15ppt

• Spread: 

  • 80% infection oyysters in GoM and along the US atlantic cost

  • Not as devastating effects in the gom due to increased ouster growth rate

  • Spreads via hemolymph through tissues: causes deterioration and organ failure  

• Depleted host energy resources, causing decreased growth and reproduction and increased mortality 

Amyloodinium ocellatum

• DINOFLAGELLATE

• Parasitic 

• Spread:

  • Infects warm water marine and brackish water bony fish 

• Causes extensive mortailityes in aquaculture systems 

• Development: 

  • Trophont (feeding stage)

  •  Tromont (reproductive stage): can produce up to 250 dinospores for 1 tromont 

  • Dinospores: infective stage

Hematodinium spp

• DINOFLAGELLATE

• Crab parasite 

• Symptoms: 

  • Bitter crab disease

• Survivial range: 12-61 ays 

• Simialr lifecycle to Amyloodinium 

Aphanomyces invades

Epizootic Ulcerative Syndrome

• Oomycete

• More than 100 estuarine and reshwae=ter species are susceptible to EUS 

• Siginficaint impacts for aquaculture industries 

• Life cycle: 

  • Direct (no intermediate host) 

  • Has an sexual and sexual life stage 

• Spread: 

  • Emerged in east asia in the 70s

• Symptoms: 

  • Ulceratie lesions 

  • Granulomatus response 

Crypotocaryon irritinus

• Cilitate 

• Pariaist of wild and cultured MARINE fish

  • Prevalent in ornamental fish culture 

• Symptoms: 

  • Internal parasite, encapsulated in the epsidermis 

Neobendeia

• Helminth Ectoparasite that lives on fishes skin 

• Particular problem in net pen aquaculture 

• Life cycle: 

  • Oviparous: consists on eggs and hatching eggs

  • Viviparous variety: free swimming larvae that attach themselves to fish

Caligus

type of copeopod parasite

“sea lice”

symptoms:

• Consumption of fish skin

Life cycle: coepodid becomes chalmus→ chalmius stages molt into pre-adult stage→ motile adult stages→ mate on fish skin→ eggs hatch as free swimming nauplius

lepeoptherius

type of copepod parasite (sea lice) that is prolific in the atlatnic ocean, more pathogentic to atlantic fish than pacific s

Morbidity

illness in the system over a period of time

incidence

frequency of disease in a population over time in relation to the population in which it occurs (new cases/time)

prevelance

frequence of a disase at a particular point in time in relation to the population ( % infected)

V. vunlificus

type of vibrio bacteria that causes foos posinioning and systhamtic infecions in humans, found in shellfish