Aquaculture

Question 1

What are some features of fishes biology and behaviour?

Answer 1

• Biologically ancient and diverse organisms
• Can change behaviour, appearance and even sex in response to environment
• Social, spatial and memory processes
• Sex is not genetically determined and often changes in response to age, physical or social environment

Question 2

Describe excretion in fresh vs salt water fish

Answer 2

• Freshwater fish produce large volumes of dilute urine

- Saltwater fish suffer with dehydration so to compensate they have a large water intake and keep urination to a minimum

Question 3

What features are temperature dependant in fish?

Answer 3

Everything temperature dependent:
- Growth, immunity, reproduction, healing, etc.
- Feeding: even have periods of inappetence
Duration of any biological process time & temp dependent:
- Degree days = ◦D
- Average water temperature in ◦C x number of days

Question 4

What is aquaculture?

Answer 4

Aquaculture is a form of farming

• Any type of aquatic animal or plant
• Seaweed, oysters, shrimps, fish, crocodiles etc.

Question 5

Compare growth of fisheries vs aquaculture?

Answer 5

• Fisheries: many issues with declining stocks

* Aquaculture: steadily expanding

Question 6

Name two spp produced in temperate freshwater ponds

Answer 6

Rainbow trout

Common carp

Question 7

Which spp is produced in temperature seawater cages?

Answer 7

Adult salmon stages

Question 8

Which spp are produced in tanks?

Answer 8

Fresh water = trout and salmon

Saltwater = cod

Question 9

What is the importance of processing of animals from intensive farms

Answer 9

Creates a lot of jobs – vital part of local economy

Question 10

Describe the life cycle of salmon

Answer 10

• Adult salmon come back to freshwater to spawn – rapid flowing water
• Females pick a gravel part of the river bed where eggs are released and fertilised over time, at different points of the bed
• Temperature dependant hatching
• Alevin (stage after eggs) stay within gravel and obtain nutrients through absorption of the yolk sac
• Fry (stage after alevin) feed on plankton before growing to parr
• If big enough, some migrate to the sea (have to undergo smoltification), return to the home river when they want to spawn again

Question 11

How is reproduction controlled in aquaculture systems?

Answer 11

• Hatching tray – single layer of eggs in each tray: receive cold, oxygenated water constantly
• Production tanks for juveniles
• Ponds and raceways
• Growing cages in the sea

Question 12

Ornamentals are also known as?

Answer 12

Pet fish

Question 13

Describe production and popularity of ornamentals

Answer 13

• Many ornamental fish come from retail markets in Asia, but an increasing number are coming from eastern Europe
• Worries about the increase in popularity due to being taken from their wild habitat
- ~£400 million spent annually on keeping pet fish
- Fish 3rd most commonly kept pet after dogs and cats