Chapter 12 Flashcards
What affects light penetration?
Turbidity
What does marine life at depths rely on?
Food produced near the surface
What does algae absorb?
Nutrients from the surface
What is an example of abundant and non-abundant nutrients?
Abundant - CO2
Non-Abundant - Phosphates
How are phosphates increased in the photic zone?
Runoff from rivers
Areas of upwelling
What are the 2 types of Demersal fishing?
Trawling
Long Line
What is Demersal fishing?
Fishing for species who live on the seabed
What is Pelagic fishing?
Fishing for species above the seabed
What are the 4 types of Pelagic fishing?
Trawling
Drift nets
Purse seining
Pelagic long line
What are shellfish traps?
Baited traps to catch crustaceans
What are the environmental impacts of fishing?
Population decline
By-catch
Ghost fishing
Habitat damage
What are the 3 reasons why by-catch may not be wanted?
Immature fish
Catch quota is already reacher
Species with no commercial value
What is ghost fishing?
Discarded fishing gear can still trap and kill species
What habitat damage can occur?
Seabed damage Coral reef impact Seagrass beds Dynamite fishing Food web impacts
What methods are used to reduce environmental impacts of fishing.
Catch Quotas
Fishing equipment design and use
Restricted fishing effort
Restricted Fishing methods
How can fishing equipment design and use be changed?
Mesh Size Mesh Design Escape Panels Acoustic deterrent Hook Shape Decoys Sinkers Night fishing Biodegradable and radio tracked equipment
How can fishing methods be restricted?
Ban Drift nets Bans of demersal Trawling No-take zones Turtle bycatch Closed-season Minimum catchable size Maximum catchable size Protected individuals Captive rearing and release
How can fish populations be monitored?
Breeding rates
Overfishing
Maximum Sustainable Yield
Why might data be difficult to collect?
Species are mobile and move long distances
Distribution of fish populations is often uneven
Collecting representative data may be impractical
What data can be collected from fish catches?
Catch size
Catch per unit fishing effort
Mean fish size
Mean age
What are the principles of aquaculture?
Extensive involves minimal inputs
Extensive may be for commercial purposes
Intensive may involve artificial control
What 2 factors affect species selection?
Local conditions
Market demand
What are some desirable characteristics?
Disease resistance
Rapid growth rate
Good appearance
How are rainbow trout controlled with gender?
Female fish given male hormones which allows them to reproduced only producing female offspring which taste better
What increases the risk of pests?
High stocking densities
No flow in tank
What decreases the risk of pests
Low stocking densities
Flow created in tank
What abiotic factors are there?
Temperature
Dissolved oxygen
Daylength
Water flow
What happens in extensive oyster auqaculture?
Oysters are bred from selected parents
Predators are removed
What happens in Salmon aquaculture?
Fish with desirable characteristics are chosen
Adult fish are stripped of reproductive cells
These cells are fertilised and bad eggs removed
Once hatched are grown in tanks
What are control of factors that can affect salmon aquaculture?
Weirs are used to aerate the water
Water flow is kept high
Water flow direction is constant
Food chain is controlled to increase efficiency
What is an IMTA?
Integrated multi-trophic aquaculture - polyculture where species from different trophic levels benefit from each other
What are the 3 types of IMTA?
Fed aquaculture
Inorganic extractive aquaculture
Organic extractive aquaculture
What is aqaponics?
Combines hydroponics with aquaculture
What are the 3 types of aquaponics?
Suitable hydroponics species
Suitable aquaculture species
Rice-fish system
