Principles of aquaculture Flashcards
What is aquaculture?
Aquaculture or farming in water is the aquatic equivalent of agriculture or farming on land.
What is the aim of aquaculture?
Aims to control aquatic ecosystems so that more food enters the human food chain
What is the differnce between intensive and extensive aquaculture?
Extensive is more natural with few interventions while intensive is very artificial and controlled by humans
What is extensive aquaculture?
Extensive aquaculture involves aquatic organisms farmed in enclosed structures placed within natural habitats (such as along the coastline, rivers, and wetlands), with minimal human input and relying more on the surrounding environment.
Will extensive aquaculture be commercial or subsistence?
Can be both
What is intensive aquaculture?
Artificial control of all abiotic and biotic limiting factors to maximise productivity and profitability for commerical purposes
What 3 ways are species selected for use in aquaculture?
Local conditions
Species adaptations
Market demand
How do local conditions affect the species grown in aquaculture?
Temperature and quality of water will control the species that can survive
How will species adaptations affect the species that can be used for aquaculture?
Certain species have adapted to certain conditions that they need for survival/ optimal growth
What are some examples of species adpatations for aquaculture?
salmon and trout are suited to cooler temperate regions
Tilapia thrive in warmer tropical regions
Marine species live in coastal areas
How does market demand affect what species can be grown in aquaculture?
MEDCs mainly grow carnivourous fish (salmon and trout) due to flavour and popularity with consumers
LEDCs grow traditional species which are commonly herbivores or omnivores (carp and tilapia)
What characteristics might be found in adult that have been selected for breeding? (aquaculture)
Disease resistance
Rapid growth rate
Good apperance (broght colours)
WHat are the chromosone combinations for male and female fish?
Male- usually have one X and Y
Female- 2 X’s
How can gender of fish be controlled? (aquaculture)
Hormonally regardless of genetics
If young fish are given female hormones they will develop into female adults and vice vers with male hormones
Is there a desired gender for aquaculture?
Desirable gender depends on the species
How is the gender of rainbow trout manged and why do farmers do this?
Female rainbow trout has a better flavour
Some female fish given male hormone testosterone meaning they are still genetically female but are functionally male and produce sperm/ which has X chromosone (only females produced)
How is the gender of Tilapia managed and why do farmers do this?
Males preferred
More energy efficient and grow larger
Treating young fish eith male hormone testosterone produces all male fish so bigger, more marketable harvest produced
What are triploid fish?
Infertile fish in aquaculture that have been sterilised to prevent wild gene pool impacts if they escape
How are triploid fish infertile?
they have 3 sets of chromosone this is acheived by heat and pressure treating eggs soon after fertilisation
Why are fish at increased risk of being infected by disease or pests in aquaculture?
High density of stock promotes easy transmission
Increase contact and collisions between fish increasing spread of pathogens and parasites
How can the risk of infection, disease and pests in aquaculture be reduced?
Where water flows between tanks with fish of different ages flow from young to old fish reduces risk of continued spread from old to young
Lower stocking density
Pesticides or biological control
Tanks with circulating water currents ebcourages fish to move in same direction so less collisions
What is an example of biological control in aquaculture?
Wrasse which eat lice that carry disease
What external species can cause problems for aquaculture?
Mainly a problem in extensive aquaculture
Competitors wild species in the water
Predators such as seals and bird species
What ways can the effect of external species be reduced in aquaculture?
Fencing
Netting
Bird scarers
Culling
Licenses in some UK areas to kill seals and cormorants.
