FISH Flashcards
What are finfish?
Aquatic vertebrae with fins for locomotion and gills for respiration
What are the main aquatic species?
Salmonids —>Atlantic salmon, pacific salmon, trout
Freshwater species —> carp, catfish, tilapia
Marine species —> bream, bass, cod, halibut
What are the different types of shellfish?
Crustaceans
Molluscs
Echinoderms —> sea urchins
How to crustaceans respire
Branchally (through gills)
What is the anatomy of a mollusc like?
Coelemic animals
Unsegmented body
What is the common body plan of a mollusc like?
Foot- for anchoring, locomotion or predation
Radula - toothy tongue
Mantle- produces the shell
Shell
Visceral mass- internal organs
What fish species are commonly produced in UK?
Atlantic salmon
Rainbow trout
List the species of crustaceans commonly cultivated
Lobster
Crab
Shrimp
Barnacles
Crayfish
Which mollusc species would you commonly see in aquaculture
Clams
Cockles
Oysters
Octopus
Squid
How does a cephalopod differ from other molluscs?
More advanced nervous system
well developed eyesight that is used in finding prey
Can change colour, shape and texture to camoflague
Have tentacles
What is aquaculture?
The growth and reproduction of aquatic organisms in a controlled/ semi controlled environment
What are the four different systems of aquaculture from lowest to highest intensity?
Ponds
Raceways
Cages
Recirculating aquaculture systems
Which aquatic species have flow through systems?
Salmonids
Brass
Bream
Shrimp
Which aquatic species use recirculation as water management system?
Juvenile production of Salmonids, bass, bream shrimp
What aquatic species used batch culture as water management system?
Shrimp
Early larvae of marine fish
What are pond systems and what species are commonly used?
Enclosed water areas, least intensive, depend on natural processes
Salmonids
Shrimp/ prawns
Catfish
What are raceways and what species tend to be cultured this way?
Rectangular, single pass systems
Built above or below ground
Gravity flow of water
Trout, Carp, prawns
What are the advantages and disadvantages of using cages?
Pros;
Easy stocking
Easy feeding
Easy harvest
Cons;
Little environmental control
Suspect ability to predators
Little water quality control
Quick disease spread
Salmonids
Seabass
What is RAS like?
Most intensive system
Can be located anywhere
Commonly used in juvenile stages
Salmon, trout, eel, sturgeom
What transitions do salmon do in their life?
Transition from freshwater to seawater
Goes from RAS/ pond into open water cage
What is smoltification
a complex series of physiological changes where young salmonid fish adapt from living in fresh water to living in seawater
What physiological changes do salmon undergo during smoltering?
Altered body shape
Increased skin reflection (turn silver)
Altered behaviour
Change in blood chlorides
Change in gill ATP synthase levels
What is welfare
The animals normal biological function, its emotional wellbeing and ability to perform normal functions
How do you assess welfare on an aquaculture production unit?
Stocking densities
Feeding rates
Behaviour
Growth rates
Health status
Survival rates
Surface activity
What does the veterinary surgeons act say in respect to fish
Performing surgery on fish isn’t considered an act of veterinary surgery
So technically non vets can do it
What does the Animal welfare act 2006 state in relation to fish?
Fish count under welfare guidelines as they have a vertebrae
What does the animal welfare act 2022 suggest?
Includes cephalopods molluscs and decapod crustaceans
They dont come under welfare act, rather have been recognised as sentient beings
What are the two different types of fish?
Bony fish —> osteichtyes —> most pet and farmed species
Cartilaginous fish —> Chondrichthyes —> sharks and rays
What are the most common types of laboratory fish?
Zebra fish
What does the operculum do?
Bony flap that protects the gill
Involved in buccal pump
What do the following 4 fins do?
Caudal fin —> tail fin, largest and most powerful, provides forward momentum
Dorsal fin —> keeps fish upright and controls direction of movement
Anal fin —> helps keep fish upright and stable
Pectoral/ pelvis fin —> steering, balance and moving up and down in water
What is the lateral line?
Sense of sense organs used to detect movement, vibration and pressure gradients
What is important about the skin of a fish?
Barrier versus environment
Osmotic barrier
Lubrication
Defense against pathogens
What is the gastrointestinal tract like?
Simple and short in carnivores (more nutrient dense diet_
Longer in herbivores
What is important about liver in fish?
Largest organ
In anterior coelom
Some fish have heptopancreas
Some have pancreas separate to liver
Why are gills important?
Gas exchange
Acid base balance
Excretion of nitrogenous wastes
Osmoregulation (ion exchange)
Immune role
How much energy output is needed for osmoregulaiton
25-50%
What parts of fish are involved in osmoregulstiom
Gills, gut and kidney
How does osmoregulation work in salt water fish?
Water passively leaves fish
Fish drink large quantities of water
Salt excreted through urine, gills and digestive tract
How does osmoregulatiom in fresh water fish work?
Water passively enters fish
Production and excretion of a high volume of urine with low salt concentration
What is the role of the swim bladder?
Mechanisms for maintaining buoying and position
What are the most important things in terms of water quality?
Oxygen
Carbon dioxide
Ammonia
Nitrate
Nitrites
What are signs of respiratory distress?
Gasping (may be behavioural to gain food)
Gathering at areas of higher oxygen (water inlets)
Flared gills (trying to get water in gills)
Why is high CO2 concentration toxic?
Fish can’t excrete through gills
When is oxygen concentration at its lowest in water
In morning
How does the nitrogen cycle work in relation to fish?
Ammonia is released from fish and decaying plants, waste product of protein metabolism
Denitrifimg bacteria turns ammonia into nitrite
Denitrifimg bacteria turn nitrite into nitrate
What is the problem, with getting a new tank and how can it be solved?
Too many fish, not enough Denitrifimg bacteria
Immature filter
Start with lowest number of fish and increase every 4 weeks
What is important to consider with home tanks?
Stocking density
Species and compatibility
Enrichment
Plants (can affect O2 and CO2 conc. )
Water changes to remove nitrogenous compounds
What is difference between freshwater and saltwater tanks?
Fresh water easier to start but more open to fluctuations
Saltwater requires heating, but freshwater might not
Saltwater tanks need specialised lighting
What things are removed in RAS?
Solids filtrate
Bio filter
CO2 filter
What is pumped back in in RAS
Disinfection
Pumping and cooling
pH control
Oxygenation
What should you look at when assessing fish (still in water)
Check skin
Check respiration
Check swimming pattern
Observe rest of population and interactions
What are the two types of primary diagnostic exams?
Skin scrapes
Gill clips —> take finer filaments, not gill arch
How are radiographs done?
Setting won’t be the same as usual, due to refraction of water
Can do out of water with GA and quick shot out of water
How do ultrasounds work with fish?
Don’t get machine wet!
Don’t need gel
What are the two different types of anaesthetics and how do they work?
MS 222 —> powder and dissolved in water, but acidic so 1;1 ratio needed with sodium bicarbonate
2 phenoxyethanol —> cheap, 1 pump per litre, can be used as quadruple dose for euthanasia
Eugenol —> clove oil, not completely soluble in water
What are some common conditions seen with fish?
Dropsy —> not a disease but a clinical sign, caused by fluid build up in the body due to problems with osmoregulation
Buoyancy issues —> floating at top or bottom, usually an issue with the swim bladder
Tumours
Infectious disease
Dystocia
Polycystic kidneys
Where is blood sampling done with fish?
Tail vein
What are some ethical considerations with aquaculture?
Impacts on the environment
Welfare of fish
Suitability of species on intensive environment
Risks to wild populations
Why are zebra fish used as research models?
Genetically similar to humans
Easy care
Easier to introduce genetic changes
Very high number of offspring
