INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS CONDELL                                                      ...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS The process by which fish become used to a given environment....
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS Activated Sludge CONDELL          Process where nutrients are...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS Adsorb CONDELL          Formation of a thin film on a surface...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS Air Dryers CONDELL          Air dryers use either a heat sour...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS of the ratio of air to water, the amount of air pumped in, th...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS Algal Scum CONDELL          A floating mass of filamentous an...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS areas where there is an abundance of aluminium in the ground,...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS NaNO3 Chemical used in starting biofiltration system, especia...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS A function which can give a proportional state. Unlike a digi...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS CONDELL            Anguilliformes            Order of fish (p...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS licences may be required for their injection 4. Workers are p...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS Ascorbic Acid CONDELL          Vitamin C. Water soluble vitam...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS Superorder of fish including the order Atheriniformes. Genera...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS CONDELL            B            B.O.D.            Biochemical...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS see back flushing CONDELL          Bacteria           Usually...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS Bacterin CONDELL          A vaccine that is prepared from bac...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS Chemical treatments of the fish, where the flow to the tank/p...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS A substance used in the production of feeds to help the pelle...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS Biostatic CONDELL          A chemical which prevents organism...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS Class of animals. Part of the phylum Mollusca. Freshwater, br...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS see cyanobacteria CONDELL          Bohr Effect           Disc...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS Salty water. Generally regarded as water with a salinity of g...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS If the budget quote is in the region of the price that the cu...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS See Chemical Oxygen Demand CONDELL          Cable          Se...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS Hatching system consist of a number of stacked hatching troug...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS to use 2. Ponds with large phytoplankton populations can be t...
INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE  CARLOS Cartridge Filters CONDELL          Enclosed vessels which hou...
Diccionario acuicultura
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Diccionario acuicultura

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Diccionario Español/Inglés de términos técnicos de la industria de la Acuicultura.

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Diccionario acuicultura

  1. 1. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS CONDELL Diccionario En Inglés Acuicultura A Ablation The process of removal of the eye in crustaceans. This is done to promote moulting and/or spawning. The eye stalk is a source of GIH (Gonadotropin Inhibiting Hormone) and so its removal, reduces or eliminates the signals which are stopping gonadotropins (which start and control the maturation process) from being produced ABS See Acrylonitril Butadiene Styrene Abscess A localised area of dead tissue debris and white blood cells, surrounded by inflamed (and often infected) tissue. Absolute 100%. See also nominal Absolute pressure Pressure measured on a gauge where zero on the gauge is equal to zero pressure i.e. a complete vacuum Absorption The process where gasses, fluids and other chemicals are taken in by the mucous membranes, blood vessels and skin. Also refers to the transfer of nutrients across the cell membrane with required nutrients entering the cell and waste matter being discharged. Acanthopterygii Superorder of fish including orders such as Beryciformes, Zeiformes, Syngnathiformes, Gasterosteiformes, Scorpaeniformes, Perciformes, Pleuronectiformes and Tetraodontiformes. Largest of all superorders. Dorsal, pelvic and pectoral fins usually have spiny rays, protractile mouth. Acanthuroidei Suborder of fish (part of the order Perciformes) including fish such as Surgeonfish (Acanthurua), Rabbitfish (Siganus) Acclimation DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  2. 2. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS The process by which fish become used to a given environment. For example fish which are usually held at one CONDELL temperature, will take time to adjust to being held at a different temperature. During the acclimation period, fish may be more susceptible to pathogens and may exhibit poor appetites and food conversion rates. Acclimation may be required for changes in water quality, lighting regimes, husbandry practices etc. Bacteria used in biological filters also require acclimation to changes in water quality, during which period they may perform their function at a reduced rate. Acid A compound that contains hydrogen and reacts with a base. pH<7.0 Acid Sulphate soils Acid sulphate soils commonly occur in brackish water marsh lands, swamps and mangrove areas. The soils will often contain iron pyrite and when exposed to air or well oxygenated water, sulphuric acid is formed which can reduce the pond muds and water to pH of below 4.0 and make it unsuitable for fish culture. It can take many years of repeated filling and draining of acid sulphate soil ponds to remove the acidity from the soil. Options are to try to manage the soil with lime addition and bottom harrowing or by trying to maintain the pond full with water at all times. The oxidation of the soils is much slower in water than in air due to the smaller amounts of oxygen available. Many such ponds are now lined, as the management of such soils is very labour intensive and costly. The establishment of grass cover on the banks of the ponds can also reduce the oxidation rate of the soils and reduce the acidification of the pond through run off. Other suggestions are that in areas of acid sulphate soils, ponds should not be dug, but dams, banks and levees built above the ground level using top soils from the inlet and outlet channel construction. the disadvantage of this is that the ponds must be filled by pumping and are at increased risk from leakage and erosion of the banks. Acidity This refers to the amount of buffering that water requires to bring the pH to 7.0, neutral. Acipenseriformes Order of fish (of infraclass Chondrostei) which includes fish such as Sturgeon (Acipenser) and Paddlefish (Polydon) Acrylonitril Butadiene Styrene Type of plastic. Abbreviated as ABS. Often used for pressure pipes. Usually solvent welded. Can be directly solvent welded to U-PVC. High impact strength. High abrasion resistance. Non toxic. Taint Free. Operating temperature range - 40oC to +80 oC. Not resistant to organic acids, ozone. Partially resistant to chlorinated water. Sponsored link - Pisces Engineering for quality abs pipe and fittings Activated Carbon Available in granules (GAC) or powder. Granules are usually more practical for commercial use. Removes negative ions o from the water (such as ozone, chlorine, fluorides etc.) Once used it can be recharged by heating to 900 C. Not generally financially viable for commercial systems. Sometimes used in small hatcheries, especially where mains water is being used and chlorine and other chemicals added to the water must be removed. DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  3. 3. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS Activated Sludge CONDELL Process where nutrients are kept suspended in the water by pumping or more commonly aeration. A mixture of free floating bacteria and algae utilise and convert the nutrients through processes such as nitrification and photosynthesis. Fish are reared in the ponds, usually at stocking densities of below 15 kg/m3. The fish in such systems will often taste muddy and must be kept in clean water for a period of up to one week prior to harvest. Such systems are used in some countries for fish such as tilapia. They enable higher stocking densities than normal, static green water systems (ponds). The systems are limited to areas where there is sufficient year round light and temperature for the bacteria and algae to perform. The systems are more difficult to control and predict than more conventional water treatment systems such as recirculation units, and due to the high B.O.D. in the water, the energy required to add oxygen to the water is often higher than the pumping costs which would be associated with recirculating the water to a separate treatment system where a lot of the B.O.D. could be removed from the system. Acute A rapidly developing disease or process. Used to describe a disease outbreak where the stock are rapidly affected, often dying without showing many symptoms. The term acute is not used to describe how severe a condition is, only the speed at which it is developing. See also Chronic Acute catarrhal enteritis Another name for Infectious Pancreatic Necrosis (IPN) Acute toxicity Causing death within 96 hours pr less after a brief exposure period. Ad libitum To the limit. In respect of feeding this term is used to describe when the fish are fed freely until they reach satiation point Adipose tissue Body tissue which is able to store high amounts of neutral fats. For example the adipose fin found in Salmonids and some other species. Adjuvant A compound added to a vaccine to increase the immune response. Adrenal Glands Glands responsible for production of some hormones. The inner section of the adrenal gland produces adrenaline and non-adrenaline. The outer part of gland secretes small amount of sex hormones (androgens and oestrogens) as well as corticosteroids. Located about the kidney. DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  4. 4. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS Adsorb CONDELL Formation of a thin film on a surface Aeration The process where air and water are mixed. This may be in the form of bubbling air into water, or letting water fall through the air. The process is usually used to increase the oxygen concentrations in water. The efficiency of aeration equipment is determined by the amount of surface area interface between the water and air and the energy required to produce that interface. A summary of the devices used and their corresponding efficiencies is shown in the table. It is also used for other processes such as degassing, mixing and destratification. Aerobic The name given to a process which requires oxygen. For example aerobic bacteria, require oxygen to live. The opposite of aerobic is anaerobic. Aeromonas salmonicida Gram negative bacteria that is the causative agent of the disease Furunculosis. Aetiology The cause of a situation or problem. Agitator A device which causes turbulence such as a paddlewheel or other device with rotating blades / parts. Air Combination of gasses making up the earths atmosphere Typically 78% nitrogen , 21% oxygen, 0.9% argon, 0.03% carbon dioxide with the remainder being a mixture of trace gasses plus water vapour. Air Cooling This process uses towers or columns, packed with media to break up the water as it falls. The water forms a thin film on the media as it runs across it. If air is blown through the tower, it will cool the water as it passes across it. Cooling is achieved in two ways - Evaporative cooling, where heat is lost into the air as the water evaporates (the same way that if you put a solvent on your hand it feels cool as it evaporates), and conductive cooling where, if the air is cooler than the water, heat will pass directly into it. Trickle Biological Filters can also be used as cooling towers if air is blown through them. Air cooling can be very efficient, depending on the relative water and air temperatures. Air Curtain see Bubble Curtain DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  5. 5. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS Air Dryers CONDELL Air dryers use either a heat source or a chemical (such as the silicon pouches, that are found in packaging for items like shoes to protect the products from rotting) to remove the moisture from air. They are mainly used to dry air before it enters machinery such as an ozone generator. Air dryers usually either use refrigeration techniques or chemicals which absorb the moisture and require replacing. For large application, refrigeration is usually the choice because of the cost and management time of the chemical replacement option.. Air - Friction loss See Friction Loss - Air Air Lift see Airlift Air Lock Air locks are pockets of air that form in pipes, if there is nowhere for the air to escape to. Bubbles often get drawn into pipes as a result of vortexes at inlet points, or if the pipe entrance is not fully submerged. Bubbles can also form in pipes as a result of gas supersaturation. If the pipe travels in an upward slope at some stage, and then slopes down again, there is a risk that the air will collect a the highest point in the pipe. This can then restrict or even stop the flow of water through the pipe. The solution is to either ensure that pipes always slope downwards, an air vent, or air purger at the point where the air collects in the pipe. Air Purger A device used to expel air from piped water systems. Typically the device has an internal float. As the air builds up inside it, the float falls, opening a valve at the top. The water pressure in the pipe pushes the air out. As the device fills back up with water again, the float rises and the valve shuts. Air stripping The removal of dissolved gasses from water by a mechanical means which involves the movement of air across water. The stripping of carbon dioxide is relatively easily achieved, stripping of supersaturated gasses is easy down to a saturation level of 103-105%, after this it becomes increasingly difficult, and requires increasing amounts of energy to remove the gas. Vacuum systems can help achieve 100% or below. Stripping of ammonia from water is only cost effective at pH levels of higher than 10.0 and therefore not relevant to fish farming. A small amount of ammonia can be stripped by air at lower pH levels, but the amount is usually insignificant when the total ammonia production is taken account of. See also degassing Airlift A contained column of bubbles and water used to pump, provide flow or current. The air lift uses a bubble source (usually a diffuser) to supply bubbles to the bottom of a column (often a pipe or similar). As the bubbles mix with the water, they create a mix which is less dense than water alone. Because of this, gravity has less effect on the water and it rises higher than the water around the column, which has no air in it, and is therefore denser. An opening at the top of the column allows the water/air mixture to escape. The head and amount of water that an air lift can pump is a function DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  6. 6. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS of the ratio of air to water, the amount of air pumped in, the depth of the diffuser, the ratio of the submerged part of CONDELL the column to the part of the column that protrudes form the water and the diameter of the pipe. Air lifts cease to work so well once the bubble to water ration becomes so high that the bubbles begin to join together and form much larger slugs of air. Airlifts are also sometimes used on cage farms, taking the water and any feed / faeces in it, from the bottom of the cage to the top, so that the farmer can see if his stock are eating all their feed. They have also been used in cages as fish pumps. Alevin The life stage of a fish when the yolk sac is still present. Also called sac fry. Algae Algae are simple celled plants and (like all plants) contain chlorophyll. This traps energy from the sun and uses that energy to convert nutrients and carbon dioxide (which are dissolved in the water) into growth. When grown in a hatchery, the growing and multiplying algal cells are collectively known as a culture. The main form of algae that is of interest to aquaculture is collectively known as unicellular. These consist of free floating cells of algae which make the water look green or brown, depending on the colour of the algae. There are many different types of unicellular algae but only a few are nutritionally suited for good growth. These are divided into two types; flagellates, which can swim by the action of one or more flagellae and diatoms, which have an outer shell made of silica. Some of the more commonly grown species and their sizes are listed in the table. Other forms include filamentous, which are strand like colonies of algae, which usually form dense mats or clumps, and blue-green algae, more commonly referred to as cyanobacteria. As well as being grown for food for the fish and also as food for zooplankton, which are then fed to the fish, algae impacts on aquaculture in other ways. These include algal blooms, taints, oxygen depletion, supersaturation and fouling. Algae control Algae can be controlled by either chemical (see herbicides), mechanical or biological methods. The mechanical methods generally involve light elimination (by floating black polythene or black bubble wrap). Filamentous algae can be removed by netting or dragging out. Care should be taken when using light elimination as the dying algae can result in high oxygen demands and lead to fish kills. Biological methods involve the used of species such as silver carp (Hypothalmichthys molitrix) which eat the algae. Algal bloom An algal bloom occurs when light, temperature, water currents and water quality (especially the amount and type of nutrients in the water) combine to form perfect growing conditions for a species of algae. The algae multiply very fast and depending on their colour, the water turns green, blue, red or brown. Algal cell counts in the water generally exceed 5 million per litre. The algae can cause damage to the fish by suffocation as it takes all the available oxygen out of the water for the purpose of photosynthesis or by causing the gills to become clogged with algae and function poorly. Certain species of algae (e.g. the blue green algaes) can produce a toxin which is poisonous to fish and can cause mortalities. Algal blooms are particularly common in areas where there is a nutrient build up in areas of poor water exchange, such as beneath cages or in static ponds where fertiliser and/or artificial diets are used. The only method to ensure that algal blooms do not occur is to remove the nutrient source. Once all the available nutrients have been used up, the algae mass reaches a critical point where it can no longer sustain itself and dies off (often very quickly). In static ponds, the algae cell mass is retained in the pond and is broken down, releasing the stored nutrients. This cycling of nutrients leads to a recurrence of the bloom (although sometimes with different algae species) at a later date. Blooms typically occur in the Spring, when the rising water temperatures, increased daylength and light intensity enable algae to multiply and make use of any available nutrients that have built up in the water during the Autumn and Winter (either as a result of breakdown of previous algae blooms or new nutrients entering the system). After the Spring, when all the nutrients are used up, the algal mass dies off and is broken down into its constituent nutrients and made available again. This often causes a second bloom in the late summer / early Autumn. The term "red tide" is often used to describe blooms of certain species of algae which contain red or orange pigments. these pigments can give the bloom a vivid red / orange colour, especially when the bloom dies off and the green chlorophyll that masks the pigment is reduced and the colour of the pigment shows through. DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  7. 7. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS Algal Scum CONDELL A floating mass of filamentous and/or unicellular algae which can restrict the penetration of light to the water column. It can be removed either physically, by mechanical filtration or by biological filtration which will remove the nutrients that it depends on for growth. Alginates Derivative substance of seaweed, used sometimes as a binder in feed formulation. Alien A non-native species for the area Aliquot A single dosage of a drug or a chemical which is in solution. Alkaline A compound which has an excess of hydroxide ions. A substance which combines with acid and neutralises it, forming a salt. pH >7.0 Alkalinity Alkalinity is a measure of the concentration of bases in the water and the capacity of the water to accept acidity (I.e. its buffering capacity). Alkalinity is usually measured as either mg/l (milligrams per litre) CaCO3 (Calcium Carbonate) or meq (milli-equivalents). 1 meq = 50 mg/l CaCO3. The ideal range of alkalinity for fish farming is 20 - 300mg/l. Below 20mg/l the water will have a very low buffering capacity, and any acids that are washed into the water (for example after heavy rain has soaked through peat), will cause a big fall in pH. Such fluctuations of pH are harmful to fish. Water with low alkalinity can be treated with lime. High alkalinity levels can sometimes lead to a condition in the fish called nephrocalcinosis. Allele A gene (in a diploid fish) is supplied with a single allele from each of the parent fish. For example the gene may be responsible for the expression of eye colour, with one allele giving a blue colour and the other a brown colour. One allele becomes more dominant over the other (which is termed recessive) and this denoted the expression of the gene. In the case of the eye colour, the blue allele may be dominant in which case the gene will make the eyes blue. Altitude Altitude has a bearing on the amount of dissolved gas (such as oxygen) that water is capable of holding. At higher altitudes the water contains less oxygen than at lower altitudes. Aluminium Aluminium is used in many farms as screens, hatching trays and also as a construction material for some items of plant such as filters etc. The material is generally long lasting, but use in very acid waters should be avoided as this can lead to the build up of aluminium in the water, which is toxic to fish. Its use in seawater systems should also be avoided as the seawater oxidises the aluminium. Where aluminium is not suitable, 304 or 316 stainless steel should be used. In some DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  8. 8. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS areas where there is an abundance of aluminium in the ground, and acidic waters prevail, dissolved aluminium can CONDELL cause severe problems to fish. These problems most often occur where there is run-off from industry/mining activities Ambient The normal (natural) environmental conditions. Amino acid The building block of proteins. The quality of a specific protein source is down to its make up of different amino acids Ammonia The unionised form of ammonia (although sometimes used to express the total ammonia (i.e. unionised and ionised). Symbol NH3. Toxic to fish. See unionised ammonia for more details on toxicity. The amount of ammonia produced by the fish is approximately 0.03 x feed (for commercial diets). Therefore for every 1000g of feed that is fed 30g of total ammonia is produced. This is excreted by the fish in the urine and across the gills. The ammonia production will vary throughout the day with the 0.03 value being the average. In systems where the feeding regimes are confined to a few large feeds over a short period, the maximum ammonia production at any time may be twice this amount, with corresponding periods of very low ammonia output. Ammonia stripping see Air stripping Ammonia-nitrogen Ammonia-nitrogen refers to the part of ammonia that is made up of nitrogen. The chemical symbol for ammonia is NH4. This means that it consists of one Nitrogen atom (N) and four Hydrogen atoms (H). The atomic weight of Nitrogen is 7, and that of Hydrogen is 1. Therefore a molecule of ammonia has a total atomic weight of 11 (7+1+1+1+1). Nitrogen therefore comprises 63.6% of the total weight of ammonia (7 / 11 x 100%). When ammonia concentrations are referred to as ammonia-nitrogen, they are only referring to the nitrogen part of the compound, which is only 63.6% of the ammonia concentration. The term is used in aquaculture, as it is the nitrogen part of ammonia, which is used to calculate how much nitrite and nitrate will be produced, following biological filtration of the ammonia. To convert ammonia to ammonia-nitrogen, multiply by 0.636. To convert ammonia-nitrogen to ammonia, multiply by 1.57. See also ammonia Ammonium The ionised form of ammonia, symbol NH4. Non toxic to fish. See also Unionised Ammonia, Ammonia nitrogen Can be used in some forms as a herbicide against Elodia sp. (common name Canadian Pond Weed). Applied at 225kg / ha to dry pond as a preventative measure. Ammonium Chloride NaCl. Chemical often used to start biofilters. Ammonium Nitrate DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  9. 9. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS NaNO3 Chemical used in starting biofiltration system, especially where there is denitrification in the system which CONDELL requires the nitrate source. Amorphous Without any fixed shape Amplitude Term used to describe the height of a wave. The measurement is taken from the crest to the mean half way point to the trough. Anabantoidei Suborder of fish (part of the order Perciformes) including fish such as Gourami (Osphronemus). Able to breath air through specially adapted respiratory organs Anadromous A fish which spawns in freshwater and lives most of its life at sea e.g. Atlantic Salmon (Salmo salar) Anaemia A reduction in the number of red blood cells. Limits the ability of the blood to carry oxygen and other nutrients around the body, and excretion of waste products (such as carbon dioxide). the reduction in the red blood cells results in the starvation of tissues of oxygen and other nutrients. Anaemic fish typically show pale gills, due to the reduced number of red blood cells. Anaerobic The term used to describe a biological process which occurs without the need for oxygen. Often used to describe types of bacteria and bacteriological processes such as denitrification. Anaerobic bacterial activity can be seen in the bottom muds of ponds, lakes etc., where organic matter is broken down without the availability of oxygen. The thin crust of the surface muds, prevents the oxygen from penetrating through to lower layers. Such anaerobic breakdown in muds can result in the production of hydrogen sulphide, which can be toxic to fish. Anaesthetic An agent (usually chemical) which can cause partial or complete loss of sensory awareness, ability to feel pain and ability to carry out muscle movements. Not all anaesthetics achieve the full range of effects (e.g. hypnotics such as metomidate and etomidate, which do not block pain well), and a number of the common drugs which have pain- relieving (analgesic) ability may stimulate marked transient stress via their depression of the subjects central nervous system. Anaesthetics are sometimes used in aquaculture for the following purposes ; transportation, prior to slaughter, broodstock handling/injections etc., administration of vaccines/drugs, tagging. If anaesthetics are to be used for stripping broodstock, the fish must be rinsed and dried before stripping as any anaesthetic can affect sperm motility and egg quality. A list of the more common anaesthetics used in fish culture are given below. Before using then one should check the following: 1. If they are licensed for use in your country, 2. Test a few fish first as the speed and depth of anaesthesia varies fish size, species and water quality, 3. Special licences may be required for the use of anaesthetics, especially if they are to be injected, 4. Workers are protected from the effects. See also Sedation, Carbon dioxide Analogue (1of 2) - Signal. DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  10. 10. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS A function which can give a proportional state. Unlike a digital signal which can only instruct a device to be on or off, an CONDELL analogue instruction can tell a device to be at any number of states between on and off. For example a digital signal can only turn a pump on or off., whereas an analogue signal can not only turn the pump on or off, but can also regulate the speed of the pump (e.g. 20%, 30%, 40% of full operational capacity etc). Analogue signals are increasingly being used for dosing functions using the feedback from a probe. For example an output from oxygen probe may give a tell a controller that the oxygen concentration is changing in a tank. The controller will send out an analogue signal to partially open or close the oxygen supply valve, in an effort to maintain a steady oxygen concentration at all times. This is more preferable than having just an open or closed valve (as would be the result from a digital signal), as this can give rise to peaks and troughs of oxygen which can stress the fish. Analogue outputs come in a variety of signal types, all of which give a band of operation proportional to the controller output requirements e.g. 4-20mA band will give a value anywhere between 4 and 20mA. Other common analogue outputs are 0-20mA, 0-1volt and 0-100mV. Analogue (2 of 2) A copy of....for example some artificially produced hormones are analogues of the naturally occurring hormones. Anchor Device dropped onto the sea bed to secure a floating vessel. The best type and size of anchor for a given situation depends on the sea bed type and the angle of the anchor chain / rope. See also chain, cable and rope Anchor Ice The term given to a specific type of ice which forms under the water. The phenomenon occurs when water temperatures are almost 00C (32oF) and air temperatures are below freezing (usually < -4oC). Bubbles of very cold air are drawn into the water through water splashing (at weirs or pipe outlets) and as the air in the bubble is below freezing, the bubbles become coated with ice. This reduces their buoyancy and causes the icy particles to travel in the water column. The ice particles "stick" to each other in the water and also "stick" to the surfaces of pipes etc. Once there is a coating of ice on a surface. Other ice particles readily stick and the coating builds up. Anchor ice can cause particular problems in long pipe runs, where the bore of the pipe is gradually reduced by the thickening ice layer, and also on screens (where maters are often worsened by the fact that many screen designs cause air to be drawn through with the water.). Androgen A substance with a male hormone activity such as Testosterone Androgenesis This process involves the irradiation of the egg before fertilisation. This means that only the male parent contributes to the genetic make up of the offspring. This process then results in the offspring being all male, a desirable attribute in some species. It also allows cryopreserved sperm to be used to fertilise eggs. In this way a library of sperm from proven broodstock could be held in storage and used in the future to create off-spring with the same characteristics as the original broodstock which may have died years ago. Androgenote Offspring produced through androgenesis Entry submitted by Shmuel Rothbard DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  11. 11. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS CONDELL Anguilliformes Order of fish (part of the superorder Elopomorpha) which includes fish such as European eel (Anguilla anguilla), Moray eel (Muraena). Absence of pelvic fins, reduced pectorals and elongated body. Anion A negative ion Annulus A growth ring that is found on scales, opercula and in otoliths. Like rings on a tree. Counting of the rings can assist in determining the age of a fish and the number of times it has spawned. Annunciators Device which plays a message (e.g. as found in an alarm panel) Anoxia Oxygen deficiency in the blood cells or tissues of the body to such an extent that it causes physiological and/or psychological disturbance Anoxic Deficient in oxygen. Anoxic areas are sometimes found a few inches down in silt and muds, where organic matter has settles and has been broken down the bacteria. The upper layers of silt act as a barrier against oxygen transfer to the lower layers and so the muds become devoid of oxygen. Such situations can often occur in the bottom of heavily stocked ponds with a poor water turnover rate or beneath cages. The build up of such anoxic areas can lead to the production, and release into the water of Hydrogen Sulphide which is toxic to fish. See also Azoic zone Anterior Towards the front (opposite of posterior) Anthelmintic A chemical which destroys or expels parasitic worms Antibiotics Chemicals used to treat bacterial infections. There are many different antibiotics available. Most are administered with the feed, although some valuable fish may be injected. Antibiotics are usually given under the supervision of a veterinary surgeon, and care should be taken to follow the complete course through, to prevent the build up of resistance in the bacteria. If antibiotics are to be incorporated with the feed, this is most effectively done at the feed mill where more controlled mixing can be carried out. If carried out on site, a cement mixer is often used to mix the feed with the dry antibiotic, before finally adding a spray of vegetable or fish oil to bind the antibiotic to the pellet. The more common antibiotics and their dose rates are listed below. Care should be taken to ensure the following when using antibiotics 1. If they are licensed for use in your country, 2. Special licences may be required for their use or on farm mixing, 3. Special DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  12. 12. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS licences may be required for their injection 4. Workers are protected from contact as much as possible, 5 Proper CONDELL Withdrawal periods are observed. See also Vaccines Antibody A protein which is produced by the fish, in an effort to neutralise the effects of a foreign material (such as a pathogen) entering the body Antifouling Antifoulants are chemicals that are coated on to surfaces to prevent algae, seaweeds and marine organisms from attaching to the surface. Some chemicals that have been used in the past and some that are still used, create conflicts with environmentalists, ecologists and shellfish / crustacean farmers and fishermen. This is because the chemicals leach into the water and affect the wild stocks. Antigen A substance which is not normally found in the body, but which, if added to the body, will produce an immune response. Anti-oxidant A chemical which is added to feedstuffs to stop fats breaking down. Vitamin E is a commonly used anti-oxidant in fish feeds. Antisepsis The prevention of infection by administration of chemical agents (biocidal or biostatic) to damaged tissue. Aquathol Herbicide used to control submerged macrophytes. Applied at 18.8 litres / ha. See Herbicide Aquifer A formation of rock that holds a reservoir of ground water Artemia Proper name for the crustacean, the brine shrimp. Harvested from certain areas of the world (such as the Great Salt Lake in the USA). The shrimps lay cysts which are packed dry and have a long shelf life. Contact with water activates the cyst and the development and hatching process begins. The artemia are used to feed marine fish larvae and some freshwater species (such as cyprinids). The nutritional make up of the artemia can be boosted by the addition of several commercially available compounds. See also Live Feed Artesian Well A well where although the water table is below the ground level, geological pressures force the water up to the surface when a borehole is sunk into the water bearing rock. (which underlies an impervious rock formation.). Ground water can therefore be obtained without the need for pumping. Ascites Fluid accumulation in the peritoneal cavity. DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  13. 13. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS Ascorbic Acid CONDELL Vitamin C. Water soluble vitamin important for the construction of connective tissues. A lack of vitamin C can cause abnormalities of the spine and a reduction in the ability of the body to heal wounds. Other deficiency symptoms may be seen, depending on species Asexual Reproduction without eggs and sperm e.g. bacteria are asexual as they multiply by dividing. Asphyxia Suffocation as a result of too little oxygen or too much carbon dioxide in the blood. Can be brought on by high ambient carbon dioxide concentrations which can restrict the ability of he fish to excrete carbon dioxide. Aspirator A device for aeration and water flow creation. The device consists of a float(s), a motor, a hollow shaft and a propeller. The hollow tube is open to the air at one end and submerged at the other. The angle which the tube is mounted at is adjustable. A motor turns the propeller and creates a directed current of water. The alignment of the end of the shaft and the propeller are such that air is drawn down the shaft and mixed in with the propelled water. See aeration for comparison of efficiency with other devices. Assimilation The conversion of digested food to body tissues and fluids. Astaxanthin Astaxanthin is a naturally occurring chemical in the family of carotenoids. It is the principal pigment that gives salmonids their pink colour. It is produced for addition into fish feed in the latter part of the production cycle to ensure a good flesh colour. Astaxanthin has largely replaced the use of Canthaxanthin as the main pigment used in salmonid diets, due to adverse publicity about the latter. Pigment levels are typically in the region of 50 - 60 mg/kg feed. Modern feeds, with higher energy levels and low FCRs mean that the pigment level often has to be increased, especially if the fish are supplied to Japan or the French smokehouse markets which both demand a very deep colour. Much of the astaxanthin used in fish diets is extracted from a yeast (Phaffia rhodozyma) which contains over 0.1% astaxanthin as a dry weight. Asymptomatic carrier An animal that shows no signs or symptoms of a disease but harbours it and is capable of transmitting it to others. Such animals can be responsible for a disease, previously thought to be eradicated from a farm appearing again after a long period. E.g. A wild fish in the water course supplying the farm can become infected by the pathogen, but as it lives in a natural, stress free state it does not manifest itself as a disease. This can also be apparent in systems where different species are held, where one species is largely unaffected by the pathogen but may harbour it, the other species may be susceptible to it. Atheriniformes Order of fish (part of the superorder Atherinomorpha) includes fish such as Garfish (Belone) and Flying Fish (Exocoetus) Atherinomorpha DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  14. 14. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS Superorder of fish including the order Atheriniformes. Generally small surface feeding fish with protractile upper jaw. CONDELL Atmospheric pressure The pressure exerted by the weight of air above the measured point at any point on the surface of the earth. Atrophy Damage and wastage of tissue due to nutritional deficiency, disuse or nerve damage. Atypical Not usual in a normal condition; opposite of typical Auger Device for lifting materials. Uses a rotating, enclosed screw which lifts the material as a result of the screwing action. Used with some success for lifting fish and water together. Not as flexible as a fish pump in that the angle of lift is restricted and means that the auger sometimes takes up too much space. One advantage is that it can gently handle very large fish (in excess of 5kg), which most other types of fish transportation systems will not. Also used for conveying feed to and from hoppers. Autodialler An electronic device that is included into alarm panels to automatically dial a series of telephone numbers when an alarm condition exists. Some are linked into annunciators, which play a taped message. Autotrophic Organisms not requiring carbon in their diet. Such organisms are able to grow on inorganic salts only. Available oxygen see oxygen Axenic Denotes the absence of bacteria; opposite - Xenix Axial Flow pumps See low head pumps Axilla The region immediately behind the base of the pectoral fin Azoic Zone The area of sea/pond bed directly beneath a cage farm. Large downward flow of nutrients (food and faeces), very little life. May vary according to currents, tides etc. DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  15. 15. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS CONDELL B B.O.D. Biochemical oxygen demand. A measure of the organic substances/matter (and also chemicals which may use oxygen) present in the water. Measured in terms of the oxygen requirements of the organic matter in the water in units of mg/l. The oxygen concentration of a sample of water is taken before sealing it in a dark container, with no entrapped air, where it is held for five days at 20oC. The oxygen concentration is then taken at the end of the five day period, and the B.O.D. is the value of the oxygen at the start minus the oxygen at the end. For samples where the B.O.D. is thought to be higher than 7mg/l, the sample should be diluted with distilled water to avoid a false result as all the oxygen will be used up before all the organic matter is used up. Often several samples are taken at various dilutions to ensure a result. BOD is sometimes written BOD5 which indicates that the BOD was measured over a 5 day period. Some users may use different time periods, in which case the number of days is usually denoted (e.g. BOD3 = 3 days) but the 5 day period is the usual one used. The initials BOD may also be suffixed by "ATU" i.e. BOD5ATU. This indicates that chemicals have been added to the water to inhibit the oxidation of ammonia (nitrification). The amount of B.O.D. produced by fish is dependant on the quality of feed and the efficiency with which it is fed and converted. Typical values for high quality feed, which is fed well and converted well are in the region of 330 - 480 grams of B.O.D. for every kilogram of feed given. Bacillariophyta Also known as diatoms. Free floating, microscopic unicellular algae surrounded by a cell wall which is highly impregnated with silica (SiO2 :nH2O). Around 10,000 different species, which comprise approximately 20% of all primary production. Typically brown in colour (as a result of their containing the carotenoid - fucoxanthin). Impact in two ways in aquaculture 1. Some species (such as Skeletonema costatum (6 microns diameter), Chaetoceros calcitrans (2.5 microns diameter), and Thalassiosira pseudonana (5.5 microns diameter)) are cultured for feeding to rotifers and other zooplankton, which are then fed in the larval rearing stages of some species. 2. Some of the larger species of diatoms in supply waters can also be responsible for damage to small fish, especially in the gill lamellae. The silicon outer shell of some species is very sharp, and when water is drawn across the gill for respiration, the diatoms can scratch and cut the gills. In extreme cases this can lead to mortalities. This can sometimes be the cause of apparent respiratory problems in spring and summer, when the fish are producing a lot of gill mucus in response, without any apparent pathogen or water chemistry problem. This problem is often mistreated as bacterial gill disease, with limited success. Mechanical filtration of water can remove many of the diatoms and prevent the problem. Back flushing The general term used to describe the process where filters are cleaned. Also sometimes called back washing. The washing can be either from flows in filters a being reversed, filter beds being agitated by air or some mechanical means, or the jetting of water/air onto screens to clean them. Although many of these operations are not technically correct under this heading, they all tend to be grouped into the back washing/flushing term Back Washing DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  16. 16. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS see back flushing CONDELL Bacteria Usually single celled microscopic organism about 1 micron in diameter. See biological filtration, bacterial diseases. Bacterial diseases Diseases caused by bacteria. Bacterial diseases fall into two categories, those that affect specific areas of the body (localised) and those that affect the entire body (systemic). External bacterial diseases usually respond well to chemicals such as Chloramin T and the quaternary ammonium compounds. Systemic infections (such as Enteric Red Mouth Yersinia ruckeri) usually require antibiotic treatment. Many pathogenic bacteria are present in the body tissues and environment all the time, a trigger such as stress is often responsible for lowering the fishes defence mechanism (see Corticosteroid) allowing the bacteria to multiply. Bacterial Gill Disease A condition where the gill lamellae of the fish are infested by colonies of filamentous bacteria which cause the gills to produce excessive amounts of mucous and stick together. Both of these have the result of limiting the transfer of gasses across the gill surface and lead to respiratory stress. The disease, which in Salmonids and pond fish is usually caused by the bacteria Flavobacterium branchiophila although in warm water fish, the bacteria Cytophaga (formerly Flexibacter) columnaris is often the culprit. Small fish tend to be more susceptible to bacterial gill disease (BGD) and infections often follow periods of stress. Fish can often be seen with their opercula sticking out due to the excess mucous build up of the gills, and breathing seems rapid. Cause of most BGD outbreaks in salmonids. Infections are often reported following exposure to high ammonia, but there can also be many other non-specific causes such as high suspended solids. Treatment is usually by the use of quaternary ammonium compounds such as Benzalkonium Chloride at 1-2ppm (active ingredient) and are often followed by a treatment of Chloramine T or a similar chemical. The rational behind this is that the latter is better at killing the bacteria, but cannot effectively penetrate the thick mucous layers that have built up. In addition to the antibacterial effects, the quaternary ammonium compounds have the added benefit of "washing" most of the excess mucous off the gills). Care should be taken using quaternary ammonium compounds in soft water. When BGD, caused by C. columnaris, occurs in pondfish, external treatments for the control of columnaris disease are used. Diquat at 8.5ppm, Copper sulphate at 0.5 ppm, or Potassium permanganate at 2 to 4 ppm can be added to ponds and allowed to dissipate over time. If copper sulfate or potassium permanganate are used, treatment levels may have to be adjusted, depending on water chemistry. In soft water, 0.5 ppm copper sulfate may be toxic; and if pondwater is high in organic material, potassium permanganate concentrations must be increased. Bacterial kidney disease Bacterial kidney disease (BKD) is a systemic infection, caused by the bacteria Renibacterium salmiarum that commonly causes high mortality in populations of both wild and farmed salmonids. First recognised in wild salmon from the river Dee in Scotland in1933. As a result of this it is sometimes called Dee disease. Brook trout (Salvelinus fontinalis) would appear to to be the most susceptible species followed by Brown trout (Salmo trutta) and Atlantic salmon (Salmo salar). Causes most problems in fish which have been infected and are transferred to sea, due to the damage caused to the kidney, which makes the fish unable to cope with the changes in the osmoregulatory system. This can lead to rapid mortality. In freshwater the disease is typically chronic, but acute outbreaks sometimes occur, especially at temperatures between 13 - 18°C. Due to the grey/white lesions that occur in the kidneys, spleen, and liver; BKD has also been called white boil disease. External blisters in the skin, exophthalmia and small ulcers are typical. Often associated with infections of diphyllobothrium. Gram positive bacteria, resistant to most antibiotics. Some success has been found with Erythromycin DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  17. 17. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS Bacterin CONDELL A vaccine that is prepared from bacteria which have been inactivated by a heat or chemical treatment which does not affect the cell antigens. Bacteriocide A chemical that kills bacteria Bacteriostat A chemical which inhibits the multiplication of bacteria and so enables the animal to cope more easily with the infection. Baffle A device, such as a plate or screen, installed to alter / reduce the velocity of water. Bag Filters Enclosed vessels designed for the removal of fine solids. A mesh, or felt bag is inserted in the vessel and water passes from the inside to the outside. Filtration to less than 1 micron is possible with such filters although the cost of replacement of the bags, and the cost of pumping (due to the headloss) is high. Useful for applications such as marine hatcheries where very finely filtered water, in relatively small volumes is required. Bags may be dried out and used several times, but there is always some residue left in the bag, which limits its performance the next time round. Depending on solids loadings and how much the bag gets clogged before it is cleaned, one can typically get three to six uses from a bag , before it needs replacing. Bagging See Net Bagging Barbel A fleshy protrusion from the body, usually the mouth. Used by some fish to feel for food. Barometric pressure The same as atmospheric pressure. The force exerted by the atmosphere at any point. Most commonly expressed in mmHg (millimetres of mercury) from the original equipment used to measure this which consisted of a tube of mercury which rose or fell with changes in the pressure. Barr marks Vertical strips of colour on fish Base A chemical that has the ability to react with acids to form salts Base metabolism The minimum amount of energy required for the body to perform its vital life functions i.e. excludes the energy required for growth, activity etc. Bath Treatments DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  18. 18. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS Chemical treatments of the fish, where the flow to the tank/pond is closed off or a tarpaulin is pulled around a cage. The CONDELL chemical is added to the water, and the tank remains without any inflow or outflow for a pre-determined period, (often an hour or so). Oxygenation or aeration is usually applied to a tank, whilst the water flow is turned off. The main advantage of bath treatments is that they are easy to administer, they require no special equipment (such as dosing pumps) and they generally use less chemicals than flush treatments. Batrachoidiformes Order of fish (part of the superorder Paracanthopterygii) includes fish such as Toadfish (Opsanus) Beers Law The light passing through a coloured liquid decreases as the concentration of the substance dissolved in the liquid increases. See also spectrophotometer. Bends Gas bubbles formed in the blood stream and tissues. See gas bubble disease Benign Not a risk to health. Benthos Collective term for organisms living in or on the sediments. Benzalkonium Chloride Sometimes referred to as Roccal, or B.A.C.. A quaternary ammonium compound used as per Hyamine 3500. Typically supplied as a 10,20 or 30% solution, so care should be taken when using the chemical to ensure that the right amount of active ingredient is used. Dose rates are typically 1ppm in poorly buffered water to 4ppm in well buffered water for a period of one hour. Benzocaine A commonly used and widely available anaesthetic (ethyl-4-amino-benzoate). Administered at a dose rate of 50mg/l, with the benzocaine first being dissolved in a small amount of alcohol or acetone before adding to the water. Beryciformes Order of fish (part of the superorder Acanthopterygii) includes fish such as squirrelfish (Beryx) Bicarbonate A salt of carbonic acid (i.e.HCO3). Having an HCO3 group, such as sodium bicarbonate (NaHCO3) Bile Alkaline liquid produced by the liver and stored in the gall bladder. Assists in the digestion and absorption of fats by the action of bile salts, which chemically reduce fatty substances an decrease the surface tension of fat droplets so that they are broken down. Binder DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  19. 19. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS A substance used in the production of feeds to help the pellet stay together. Such substances include alginates and CONDELL molasses. Biochemical Oxygen Demand See BOD Biocide A chemical which will indiscriminately kill any life in the water. In addition to chemicals whish are simply toxic to all life for (example derris), this also includes chemicals (such as cyanide) which take all the oxygen out of the water. Biofilter see Biological filtration Biological Filtration The growing of bacteria colonies on a media surface over which the water passes to remove nutrients form the water. Used as an essential part of most water recirculation systems and also sometimes for treatment of outlet water from a farm to reduce waste loadings entering a river or stream to comply with regulations. Although the process of biological filtration handles many different types of waste, the main ones that we are concerned with in aquaculture are BOD, ammonia and nitrite. The BOD is oxidised by a group of bacteria called heterotrophic bacteria. These are fast growing, dominant bacteria which often comprise a high percentage of the "sewage fungus" found in tanks, pipes, sumps, channels etc. The ammonia is converted to nitrite by a group of bacteria called nitrosomonas bacteria, the nitrite is converted to relatively harmless nitrate by a group of bacteria called nitrobacter. The process of conversion of ammonia to nitrite and then nitrate is commonly known ad nitrification. Because the heterotrophic bacteria are more dominant than the nitrification bacteria, the fist 25% of biofilters often comprises a high percentage of heterotrophic bacteria and a small percentage of nitrification bacteria, the rest of the filter being mainly nitrification bacteria. Because of the ratios of BOD to ammonia in fish waste, and the way that a biological filter functions, it is generally held that if ammonia levels are kept in check by biological filtration, then the BOD will also be kept in check. The ammonia is therefore used as the main indicator that full biological filtration is taking place. There are three main types of biological filter ; trickle, submerged and fluidised. The sizing of biological filters is calculated by knowing the surface area of the media which is 2 3 being used, for example pre-formed, plastic media typically has a surface area between 100 and 800 m m (depending on the design). Once the amount of ammonia that the fish are producing has been calculated, the media surface area 2 required can be calculated by using the rule of thumb 0.4 - 1.0 g ammonia removed per day per m of media surface o o area. This figure equates to temperature operation of between 10 C - 30 C respectively. Although the process of biological filtration involves changing the water quality, sudden changes in the incoming water quality to the biological filter can "stress" the bacteria lead to poor performance. Such changes may include sudden changes in pH, flow rates, temperature etc. The processes of oxidation of BOD and nitrification are aerobic processes. Another type of biological filtration which is sometimes used in aquaculture, especially in high rate recirculation systems is denitrification. Denitrification filters convert nitrate to nitrogen gas, the bacteria in such filters are anaerobic. Biological Oxygen Demand See BOD Biomass The total weight of all living organisms. Note that for a recirculation system, the biomass should include bacteria in the biofilters. May sometimes however be used in texts to refer to the farmed stock, rather than the total of all living organisms. DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  20. 20. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS Biostatic CONDELL A chemical which prevents organisms from multiplying without necessarily killing them, which makes it easier for the body to rally its natural defences and deal with them. The used of biostatic chemicals rather than those that kill the organisms can result in increased immunity to subsequent outbreaks. Biotechnology Term used to describe the use of any living organisms in industrial and production processes. Biotic index A figure derived from tables of species with scores against them, relating to the quality of water. Used by many authorities to determine the pollution effect that a farm is having on the watercourse. Points are awarded for the type of species (those that prefer clean environments getting a higher score), the number of each species found in a sample (higher scores for high numbers) and the number of different species found (higher scores for greater number of species). The difference in scores between the inlet and outlet determines the level of impact on the watercourse. This method is often preferred by farmers as it is more generally representative of the impact rather than water quality samples, which may reflect a particular practice (such as tank cleaning) at the time of sampling. The results are open to speculation as the method of sampling may differ between operators . For example if a kick sample from a stream is taken (where the bed is disturbed and a net held downstream) the results will be dependant on the force used and duration of agitation of the bed. Biotin One of the water soluble B-complex vitamins. Birds Fish eating birds can cause great damage to a fish farm. The damage is only partially in the animals eaten by the birds. For each fish successfully caught and eaten, many others are damaged (see picture). In the case of shellfish (e.g. mussels on ropes), species such as the Eider duck can strip the ropes, partly though consumption but mainly through knocking several animals off the ropes for each animal eaten. Birds also present a threat through transmission of disease to the farm from other farms and watercourses in the area. They can also play a role as an intermediary host in some diseases such as eye fluke. Wherever possible, birds should be eliminated from entering the farm by use of netting or other scaring devices. Netting is the only complete solution as birds will very quickly become used to most scaring devices and choose to ignore them. Bird Netting Many farms are plagued by fish eating birds. These are best excluded by the complete covering of the farm with netting, which although more expensive to install than wires or strings is more effective. Biting (see Nipping) Bivalve Common term for animals in the class Bivalvia Also sometimes referred to as lamellibranchs which is actually a sub-class of Bivalvia, and contains most of the families and almost all the edible forms. Bivalvia DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  21. 21. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS Class of animals. Part of the phylum Mollusca. Freshwater, brackish and marine forms. Shell is comprised of two hinged CONDELL valves under which lie two large gills. Class includes fixed forms such as mussels and clams, and also burrowers such as shipworm and razorshell. BKD see Bacterial Kidney Disease. Black Spot Often used to refer to the black cysts caused by the intermediate stages of trematodes in fish. Blastula A ball of cells seen in the early stages of development following fertilisation. See also Cell Division Bleach (Sodium Hypochlorite) Chlorine based chemical which is sometimes used in aquaculture for footbaths etc. Their efficiency and period of effectiveness is not as good however as iodine based products as it is inactivated by organic matter quicker. They are also used for disinfection of tank walls, floors etc., however the chlorine (which is the "active ingredient") will often evaporate out of the solution as it is swilled around the tanks or across floors. The rapidly reduces the effectiveness of the product, and can lead to incomplete disinfection. Very corrosive to metals, avoid contact. Blenniodei Suborder of fish (part of the order Perciformes) including fish such as Blenny (Blennius) Bloom See algal bloom Blowers Devices which provide pressurised air, typically at pressures between 50mbar and 500 mbar. Most blowers use a turbine principle to provide the air pressure. Blowers have the advantage of being able to be all but closed off on the discharge side of the blower without damaging the blower or the discharge pipe. This is not the case with compressors. Most types of blower can also operate as low vacuum air suction pumps. Typical applications for blowers include; vacuum degassing, aeration using coarse or medium bubble diffusers, aeration using some makes of fine membrane diffusers in shallow water, provision of air for fractionation and bubble degassing of carbon dioxide. See also friction loss-air. Blue sac disease A condition of sac fry (alevins) in which the yolk sac takes on a blueish colour. Brought on by a lack of oxygen and / or high Carbon dioxide concentrations which limit the uptake of oxygen into the bloodstream. Blue tinge Irritation of the skin on fish can cause an excessive production of mucus which can give the fish a pale blue colour, especially when viewed from above in the water. Particularly associated with the parasite costia Can also be brought on by malnutrition, especially a lack of biotin in the diet.. Should not be confused with the blue colour that some naturally sterile and triploid fish (especially salmonids) can exhibit. Blue-green algae DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  22. 22. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS see cyanobacteria CONDELL Bohr Effect Discovered by C. Bohr (1855-1911). High concentrations of carbon dioxide in the blood, causes the blood to become more acidic. This has the effect of inducing the haemoglobin to release any bound oxygen in to the tissues, but has the opposite effect at the lungs/gills, where the haemoglobin is less inclined to take up oxygen. Can lead to respiratory stress and exhaustion as the fish has to breath harder to maintain its oxygen supply. Can be caused by high carbon dioxide levels in the water, which inhibit the release of carbon dioxide from the haemoglobin into the water. Bony Fishes A common term used for Teleosts. Borehole A shaft drilled into a water bearing rock or fault line in an impervious rock formation. Water is then either pumped out of the rock, or exits as a result of natural geological pressures (artesian well). Boreholes are usually sunk for freshwater supplies, but some farms sink boreholes close to the sea where they can pump seawater as it is drawn inland through porous rocks or sand / gravel. The pumping of seawater from boreholes can often bring about conflict with agriculture as, the increasing salinity of the ground water around the borehole area (salinisation), can lead to crop failure. Borehole water is sometimes wrongly assumed to be 100% disease free. Many borehole supply sources are from underground streams and channels, which may carry viruses and other pathogens. This is especially so if they are located near to a farm with earth ponds, where water from the ponds, seeps back into the ground. Borehole supplies are often high in dissolved nitrogen and carbon dioxide and low in oxygen. As a result of this they should always be degassed before use. The cost of pumping from borehole usually prohibits their use in ongrowing systems, but they are used widely in hatcheries. Water quality from boreholes tends to stay constant with temperatures higher than ambient in the winter and lower than ambient in the summer (for example almost all boreholes in temperate areas will have a temperature between 9 and 11oC all year round). see also water table and aquifer Brachyura Group comprising the crabs. Includes important aquaculture species such as Scylla serrata, the mud crab. The culture of crabs is at present restricted to either holding facilities, or facilities where the animals are held until they moult and are then sold as soft shell crabs. Brackish Slightly salty. Used to describe waters which are nether freshwater or seawater, but have a salinity which falls between the two (usually between 0 - 25 ppt.). It may also be used to describe areas (e.g. estuaries) where, due to tidal exchanges, the environment fluctuates between seawater and freshwater. Branchiae The gills (singular - branchia) Branchiocranium The part of the skeleton that the gill arches are attached to Branchiomycosis see gill rot Brine DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  23. 23. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS Salty water. Generally regarded as water with a salinity of greater than 45ppt. CONDELL Brine Shrimp see Artemia Bromine One of the most common chemicals found in seawater (full seawater contains 65mg/l bromine). Often left out of artificial seawater mixes where ozone is used in a system, as the production of hypobromous acid (a reaction of the bromine with the ozone) can cause toxicity problems to the fish Brood Chamber An area formed on the underside of some crustaceans to carry fertilised eggs prior to hatching. Also occurring in flat oysters, where the eggs are incubated on the gills. Broodstock A fish which is being kept with the intention of using it for reproduction. Broodstock are usually kept at very low stocking densities in an effort to reduce stress, promote growth rates and reduce the risk of diseases. Browsers Animals which eat continuously. Bites are not very well defined. Includes mostly herbivorous species. See also Grazers Bubble Curtain A constant stream if bubbles provided by a submerged diffuser (usually a tube type), which surrounds a specified area. the action of the bubbles forms a "wall" through which most fish will not swim. It is used for maintaining fish in an area, when screens or nets cannot be used. Fish may swim through the "curtain" in a fright response. Buccal Cavity The mouth cavity Buccal force plate The plate feature at the bottom of the mouth which is controlled by muscles to pump water through the gills and also to give a coughing action to prevent choking or clogging of the gills Buccal incubation The incubation of eggs held in the mouth by one or both of the parent fish. The movement of water through the mouth and across the gills keeps the eggs supplied with oxygen and also keeps the eggs in motion, preventing the build up of fungus or other infections. If stressed (especially if the fish feels threatened) the eggs may be swallowed. Common term for this is mouthbrooding or oral incubation . Practiced in particular by some cichlids such including tilapia (e.g. Oreochromis mossambicus) Budget Quotation An approximate quotation. Often used by companies in the initial dealings with a customer to give a guideline of the price. The budget quotation saves companies the effort of detailed quoting, whilst giving the customer an idea of price. DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  24. 24. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS If the budget quote is in the region of the price that the customer expects to pay, more information is usually sought by CONDELL the supplying company before a full quotation is offered. Used more often in the supply of systems, rather than individual items of equipment where the price tends to be fixed Buffering The process of adding carbonate and/or bicarbonate ions to water to reduce acidity and increase pH. Buffering systems are often used in recirculation systems , to counter the acidity produced during the nitrification process, and also the acidity caused by the carbon dioxide in the water. Systems usually involve using a type of lime which is either dosed into the water once it as been dissolved, used in a pelleted form with the water flowing through it (often in a fluidised bed), or added directly to sumps etc. in granular or powdered form. The effect of a buffering system used on the farm is that the operator will se a rise in the pH of the water. Systems may be manually controlled or automatically controlled by feedback from a pH controller Buildings Almost any building type can be used to house an aquaculture facility, however some aspects which can improve working and operating conditions are as follows; 1. Ventilation - poorly ventilated aquaculture buildings become very humid, and provide a perfect breeding ground for fungal spores and bacteria on spilled food etc. They are very unpleasant places for staff to work which can often result in poor staff performance. 2. Insulation - Note should be taken on the temperature of operation of the farm, especially if water is being recirculated, which can lead to a build up of heat in the system. The heat gain in to the building should be taken account of as well as the heat loss. 3. Wind loadings and snow loadings should be taken account of. One of the most common cost effective means of housing aquaculture facilities is in polytunnels. These can be built to varying degrees of insulation and lightproofness Bund An area of containment. Used to describe features such as dams, pond walls and flood banks. Also used to describe areas for containment of chemical spillage. Butt welding A process of joining two pipe sections together using a heat source to melt the pipes, and allowing the melted plastic form each pipe to amalgamate, and then letting the joint cool to form a hard plastic again. Special equipment is usually required to provide the heat for an effective butt weld. The most commonly butt welded material are polypropylene and polyethylene Butterfly Fillet A double fillet, which leaves both sides of the fish attached above the backbone Butyl Synthetic rubber compound often used in sheet form for lining ponds etc. Ability to vulcanise makes it more suitable for large ponds where multiple sheets are required. Unlike some other compounds it degrades over time in sunlight, especially where areas are exposed for long periods without covering of plants, soil or water Byssus The threads that some molluscs (such as blue mussels - Mytilus edulis) use for attachment to a substrate or cultch C C.O.D. DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  25. 25. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS See Chemical Oxygen Demand CONDELL Cable See table for specifications of different cable types. See also chain, rope Cadmium Metal, falls into the category of heavy metals. Very toxic to fish, safe levels are 3.0mg in well buffered water, 0.4mg/l in poorly buffered water. 0.2mg/l in seawater. Cage A fixed or floating enclosure used to contain fish. There are many designs of cage. Fixed designs are usually referred to as Hapas and tend to be limited to an area of several square metres. Larger systems involve a net suspended from a floating and supporting collar. Calcinosis The build up of calcium carbonate deposits in the tissues of the fish, often without harmful effects see also nephrocalcinosis Calcium carbonate Chemical symbol CaCO3. g/eq - 50, Solubility - moderate. Most common naturally occurring form is chalk and limestone. Used for increasing the alkalinity of water. See Lime for more details. Calcium Cyanamide Herbicide, used to control macrophytes. Applied at 750 kg / ha to filled ponds with no stock in. Pond should be fully drained and refilled prior to stocking. Calcium Hydroxide Chemical symbol Ca(OH)2 . g/eq - 37, Solubility - high, has a high degree of alkalinity and therefore is often used as a method of buffering systems. Applied to ponds at 1000-1200kg/ha See Lime for more details Californian hatching systems DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  26. 26. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS Hatching system consist of a number of stacked hatching troughs or trays, with grids or baskets to support the eggs. The CONDELL troughs then flow from one onto another, often with water cascading to aerate between the troughs. Used extensively for salmonids and other species with large (>4mm eggs). Calorie Unit of energy. The amount of heat required to raise 1 gram of water by 1 degree centigrade. See Energy for conversion tables Canister Filters Enclosed housings usually containing fine mesh baskets, into which filtration or other media ca be put. Often used in conjunction with activated carbon and zeolite materials. Generally designed for small flow rates, although larger units are sometimes custom built. Cannibalism The eating of ones own kind. Cannibalism can most often occur as a result of overcrowding, starvation and lack of grading (through there being a size difference in the fish great enough to enable the larger of the fish to eat the smaller fish). Some species which are left to spawn relatively naturally (e.g. tilapia) have been known to eat their young if severely stressed. More prevalent in carnivorous fish such as eels (Anguilla anguilla) see also nipping Canthaxanthin Canthaxanthin is a naturally occurring chemical in the family of carotenoids. It is a pigment that is sometimes used to give salmonids their pink colour. Synthetically produced canthaxanthin is available under the name of Carophyll pink, EEC no.E161. Astaxanthin has largely replaced the use of Canthaxanthin in salmonid diets due to adverse publicity. Carapace The hard exoskeleton shell of crustaceans Carbohydrate General term for compounds such as sugars, starches and cellulose. Contain carbon, oxygen and hydrogen. Most carbohydrates can be used as an energy source by animals, although some are difficult to digest (especially by carnivores) and so release only small amounts of energy to the body Carbon Chemical symbol "C" - The essential building block of all organic compounds. Often needs to be added to the water (often in the form of methanol) to supply bacteria in denitrification filters. See also Activated Carbon Carbon Dioxide Produced as a result of respiration by the fish and other aerobic organisms (including plants) in the system. The amount of carbon dioxide produced is directly proportionate to the oxygen consumed. For every 1g oxygen that is consumed, 1.4g carbon dioxide is produced. Carbon dioxide has the effect of increasing the acidity of the water, it is present in three different forms in the water : CO2 (free carbon dioxide, which is the toxic form), HCO3- (bicarbonate ion, and CO3- - (carbonate ion). The concentration of each is dependant on the pH of the water. The table shows the effect of pH on the proportions of different forms of carbon dioxide in freshwater. As free carbon dioxide is the form that is toxic to fish, high toxic concentrations are only normally found in neutral or acidic waters. Most surface waters, in their natural surface state contain low concentrations of carbon dioxide (<6 mg/l). There are situations however, where toxic levels may be reached : 1. Acidic groundwater can contain very high carbon dioxide concentrations and require degassing prior DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  27. 27. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS to use 2. Ponds with large phytoplankton populations can be the cause; carbon dioxide may reach high concentrations CONDELL during the night or during cloudy weather, as the plants consume oxygen as part of their natural respiration, 3.Fish transportation - carbon dioxide build up can occur in transport tanks, especially when in enclosed tanks or bags containing oxygen. Open tanks and aeration is much more preferable as it gives the carbon dioxide a chance to escape, this is especially important when transporting fish in acidic water for long journeys. High carbon dioxide concentrations are harmful to fish as the blood becomes less efficient in getting rid of its carbon dioxide across its gills. This means that some of the carbon dioxide stays in the blood, taking up a space where an oxygen molecule would otherwise have occupied. For example a carbon dioxide concentration of 25mg/l equates to almost a 50% drop in the fishes carrying capacity for oxygen. This will limit growth and make the fish more susceptible to any diseases. General guidelines for carbon dioxide concentrations are : <15 mg/l acceptable for most species, 15- 30mg/l sublethal effects including respiratory stress and the development of kidney stones (nephrocalcinosis) in some species. >30mg/l lethal to many species with prolonged exposure. Carbon dioxide can be removed / controlled by using aeration or degassing techniques, or adding lime to a pond (this should be carried out very slowly, as in acidic waters, small additions of lime can lead to large increases in the pH, which will stress the fish), approximately 1meq of hydrated -- lime can remove 2.25mg/l CO2 . Careful planning of stocking, feeding, fertilising and use of oxygenation can also help prevent high carbon dioxide levels occurring. Shallow ponds are less likely to suffer carbon dioxide problems than deep ponds. Carbonate minerals 2- A group of minerals containing the anion CO3 as the fundamental unit of their structure. Carbonate minerals are used for buffering water to increase the alkalinity. See also lime Carcinogen Any substance that either produces or accelerates the development of cancer Carnivore An animal that feeds solely on other animals. Carotenoids A group of yellow, orange and red lipid soluble pigments. A form of vitamin A. See also Astaxanthin, Canthaxanthin Carrier An animal that harbours a disease without showing symptoms. see also asymptomatic carrier Carrying capacity The amount (either expressed in weight or number) of animals that a given system is capable for supporting. The carrying capacity is limited by a factor which on farms is usually oxygen then ammonia and carbon dioxide / B.O.D. Cartilage A firm, flexible connective tissue. In vertebrates, the cartilage forms the skeleton in the early stages of development, after which it is largely replaced by bone. Some cartilage remains at the joints to give flexibility and support. Some fish, such as sharks remain with their skeletons made of cartilage, these are termed "cartilaginous". Some parasites (such as Myxosomas cerbralis) can only enter the fish and complete their life cycle, if the skeleton is still cartilaginous. For this reason, if there is a risk of infection, fish are often kept on spring or borehole water supplies until their skeletons have hardened. DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007
  28. 28. INSTITUTO DEL MAR CAPITAN WILLIAMSFUNDACIONALMIRANTE CARLOS Cartridge Filters CONDELL Enclosed vessels which house a replaceable filter membrane. The filter membrane is generally of a pleated or a woven material. Cartridge filters are used primarily for filtration of water of 20 microns and below. Disadvantages of using cartridge filters include the cost of replacement filter elements, the cost of pumping the water through the filters ( the finer the membrane, the greater the headloss across the filter) and the maintenance of large numbers of filters, should large flows be required. Cartridge filters do however have their applications in situations such as marine hatcheries, where pre-filtration is often used and very low flow rates are required. see also mechanical filtration Catadromous A fish which spawns in the sea and lives most of its life at freshwater e.g. European eels (anguilla anguilla) See also Anadromous Cataracts An irreversible clouding of the lens of the eye. Appears as a grey / white colour in the normally black lens of the eye. May be due to either physical damage sustained whilst handling, irritation from disease organisms such as Diplostomum spathacaeum, or a result of incorrect nutrition. The cataracts impair the vision of the fish. In some species, such as sight feeders like salmonids this can lead to a wasting away and eventual mortality. Some fish will however adapt and feed from the bottom of a tank / pond. This will usually result in very poor FCR and lesions to the mouth parts which can in turn lead to other infections. Poorly sighted fish are normally removed and killed to prevent them becoming stressed and risking the development of disease conditions which could threaten the rest of the stock. Catchment see Watershed Cation A positive ion Caudal Peduncle The name given to the area where the tail of a fish joins the body. Sometimes also called the "wrist". Some operators will use this area to hold the fish, although excessive struggling by the fish can cause damage to the spine and body tissues if it is not also supported elsewhere. This can result in poor fillet quality. CCVD see Channel Catfish Viral Disease Centrifugal Pumps The workhorses of most applications, centrifugal pumps use a rotating impeller that draws water into its centre and through centrifugal action, throws it outwards through vanes in the impellor and out of the pump. Efficiencies are generally in the 55 - 80% range depending on how closely the application fits the optimum curve of the pump. Cell division The process by which cells split into two copies of the original. Forms the basis of development of ova once fertilised. The single cell divides into two, these two then divide resulting in four and so on. Cephalopod DEPARTAMENTO DE INGLES: PABLO CORTEZ DIAZ – DAVID AMIGO HENRIQUEZ 2007

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