Oceans and Fisheries Flashcards
Uses of water (resource potential)
- Food
- Tourism
- Building materials
- Source of drinking water
- Transportation
- Power generation
Define aquaculture
The rearing of aquatic animals and cultivation of aquatic plants for food
Examples of building materials formed through erosional processes of the coast and on land
- Gold
- Sand
- Gravel
- Limestone
Methods of harnessing the power of the oceans
- Onshore wave generators
- Offshore wave generators
- Tidal barrages
- Tidal stream generators
Give an example of how water is used in tourism, transportation and as drinking water
Tourism- beaches, but unsustainable tourism may lead to habitat destruction
Transporation- bulk carriers, container ships, for trade
Drinking water- using desalination plants
Ocean current? Factors that influence them?
An ocean current is a continuous movement of seawater set in a direction that is driven by-
- The gravitational pull of the moon
- Wind
- Thermohaline circulation
- Tides
- Rotation of the Earth
Define thermohaline circulation
The oceanic circulation system driven by the differences in temperature and salinity
Explain the distribution of ocean currents
The warm surface water moves away from the equator in giant spiral motions.
Define gyres
A circular system of ocean currents that spin anticlockwise in the southern hemisphere and clockwise in the northern
Define coriolis effect
The effect the rotation of the Earth has
Explain the massive global conveyer belt
Since oceans do not have a uniform salinity or temperature, the warm water reaches the polar region and cools down, becoming saltier and denser leading it to sink down and travel back towards the equator. This nutrient-rich water comes to the surface through upwelling, which attracts fish stimulating the food chain
What are some key characteristics of areas where major fish populations can be found
- In shallow waters around the continental shelf with sunlight
- Around islands
- Where ocean currents cause upwelling
- In coastal waters
- Near coral reefs
What 3 elements make a key factor in the distribution
The relationship between topography, ocean currents and photosynthesis
Explain the El Niño effect
This climate cycle occurs every 2-7 years in the Pacific Ocean. These lead to weakened winds and reversed warm ocean current patterns, with drier conditions in Asia and wetter in South America.
In a normal year, warm water currents move toward the left which leads to rainy weather in Australia. This leaves cold water on the right in Peru causing high levels of upwelling and fish populations there.
However, in an ENSO year, the warm water moves back eastwards towards Peru leading to the cold Humboldt (Peruvian) current feeling overwhelmed with the heat, making it a warmer winter and heavy rainfall but no upwelling of cold water which reduces fish concentrations.
Define bycatch
The unwanted fish species and marine animals caught in fishing nets when fishing for a different species
Normally because they’re of the wrong sex, size, or species.
A lot of the time the species caught are too small and therefore discarded back dead which affects the future fish population.
