Oceans and fisheries 🙁

Potential use of the oceans

  • tidal and wave energy
  • Food , chemicals , building materials
  • Tourism
  • Transport
  • Potential of safe drinking water

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{{Why are there more fish in the continental shelf{{

{{# there are high level of light penetration and high levels of oxygen as well as abundance of carbon dioxide that helps phytoplankton because of photosynthesis{{

\ Warm currents move away from the equator they are less dense have high temperature and high salinity so less fish grow on the warm. currents

\ Cold currents have high salinity they are more dense and have low temperatures so more fish are found on the cold currents they move towards the equator

\ [[Without El Niño:[[

[[Trade winds push warm water currents towards the west when warm water is pushed towards the west . Warm water if the coast makes warm air rise and this air condenses and turns to rain .[[

[[Warm water is replaced by cold water by the process of upwelling at the South American coastline ( towards the west ). This upwelling process bring more nutrients to the surface and allows marine species to increase[[

\ [[During El Niño[[

[[Trade winds get weakened which causes warm water to reverse and go to the western side this leads to upwelling process decreasing which can cause decrease of nutrients at the surface and can cause marine life to decrease[[

\ [[During El Niño the marine life decrease towards the coastline of South America due to the upwelling being less which causes less nutrients to move to the surface and marine life declining[[

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Impact of exploitation of the oceans

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  1. Overfishing : it occurs when more fish are caught than it can replaced by natural reproduction
  2. Leads to extinction of fish
  3. Reduction of biodiversity of fish

 4. Fishing boats can pollute marine water by oil spills and chemicals

\ {{Bycatch {{

{{When fish caught are non targeted in the population being fished . It increases the rate of fish morality which can lead to some species decline{{

\ \ How to stop overfishing?

  • [[larger mesh and nets : this declines the rate of bycatch and fish morality since undeveloped fish can escape and only the adult fish are caught[[
  • [[quotas: when there is a limited number of fish that can be caught by a region[[
  • [[Closed seasons : during a particular time period a specific population of fish are not supposed to be traveled or caught[[

\ Disadvantages :

Not everyone will listen to the rules some people may fish during closed seasons

It’s difficult to monitor the amount of bycatch

Fish morality can increase since only adult fish are caught

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