Presentation is loading. Please wait.

Presentation is loading. Please wait.

Overfishing Jeff Yoo. What is Overfishing? Overfishing can be defined in many way but it all comes down to one simple point: Catching too much fish. Fishing.

Similar presentations


Presentation on theme: "Overfishing Jeff Yoo. What is Overfishing? Overfishing can be defined in many way but it all comes down to one simple point: Catching too much fish. Fishing."— Presentation transcript:

1 Overfishing Jeff Yoo

2 What is Overfishing? Overfishing can be defined in many way but it all comes down to one simple point: Catching too much fish. Fishing so much that the fish cannot sustain their population. The fish get fewer and fewer, until finally there are none to catch.

3 What is causing Overfishing? Worldwide, fishing fleets are two to three times as large as needed to take present day catches of fish and other marine species and as what our oceans can sustainably support. On a global scale we have enough fishing capacity to cover at least four Earth like planets. According to a Food and Agriculture Organization (FAO) estimate, over 70% of the world’s fish species are either fully exploited or depleted. The dramatic increase of destructive fishing techniques worldwide destroys marine mammals and entire ecosystems.

4 Appetites Doubled From the mid-60’s to 1997, the world fish consumption has leapt from 45 million tons to more than 91 million tons. This still continues to increase as the world’s population grows, along with the amount of fish being consumed per person

5 Acceptable levels of fishing Biological overfishing- occurs when fishing mortality (dead fish) has reached a level where the stock biomass has slow down its growth. Fish are being taken out of the water so quickly that the replenishment of stock by breeding slows down. If the replenishment continues to slow down for long enough, replenishment will go into reverse and the population will decrease. Economic overfishing Occurs when a fishery is making no money, primarily because an excessive level of fishing effort is applied in the fishery.

6 What’s the catch? Since the 60’s, technology has been advanced, every year there has been a 7% growth in catches, but since then theres been a little increase in catch size at least 20 of the world’s most important fisheries have disappeared in the last 25 years, with many more suffering so badly from overfishing they are unlikely to recover. As catches have gradually become smaller, so the mesh sizes used in fishing nets have decreased, allowing smaller and smaller fish to be caught. Many of these are too small to be used as food, so they are crushed to be made into either animal food or fertilizers.

7 Continued.. Fishing, using nets is indiscriminate. Any fish which get in the way of the net will be caught in it if they are too big to get through the mesh. For every one ton of prawns caught, three ton of other fish are killed and thrown away. 20,000 porpoises die each year in the nets of salmon fishermen in the Atlantic and Pacific Oceans and tens of thousands of dolphins are killed each year by tuna fishermen.

8 Technology With technologies advancing to a whole another level, fishing has never been more easier. Trawlers and fishing boats has been replaced by huge factory ships which are able to stay out at sea for weeks at a time. These factory boats have all the equipment necessary either to freeze or tin fish caught by their hunting ships, so that they need to return to their ports only when their holds are full.

9 Videos http://www.youtube.com/watch?v=zYB MZsFr1t4 http://www.youtube.com/watch?v=zYB MZsFr1t4 http://www.youtube.com/watch?v=FqZ A4FCm-es http://www.youtube.com/watch?v=FqZ A4FCm-es

10 Work Cited http://en.wikipedia.org/wiki/Overfishing#Con sequences http://en.wikipedia.org/wiki/Overfishing#Con sequences http://news.bbc.co.uk/2/hi/science/nature/31 56340.stm http://news.bbc.co.uk/2/hi/science/nature/31 56340.stm http://archive.greenpeace.org/oceans/globalo verfishing/deadahead.html http://archive.greenpeace.org/oceans/globalo verfishing/deadahead.html http://www.britannica.com/bps/additionalcon tent/18/27399470/The-End-of-the-Line-How- Overfishing-is-Changing-the-World-and-What- We-Eat


Download ppt "Overfishing Jeff Yoo. What is Overfishing? Overfishing can be defined in many way but it all comes down to one simple point: Catching too much fish. Fishing."

Similar presentations


Ads by Google