Chapter 12 Notes - Food from the Oceans The Fishing Industry

Transcription

1 Chapter 12 Notes - Food from the Oceans The Fishing Industry

2 Major World Fish Stocks Simply put the worlds fish stocks are located almost exclusively on the continental shelves. Figure 12.3 indicates that about 80% of fish harvested come from oceans. Why is this obvious? Most of the world's water is ocean therefore it would be expected that fresh water would only contain a small portion of the world's fish.

3 Figure 12.7 on page 202 might be a bit of a surprise to Newfoundlanders and Labradoreans. It shows the world regions by tonnes of fish caught. There seem to be four major fishing regions, globally speaking, and eastern North America (Northwestern Atlantic) is not one of them.

4 The 4 major fishing regions are: North east Atlantic (England/Norway); North west Pacific (Japan); West central Pacific (China/Indonesia); South east Pacific (Western South America)

5 The 4 major fishing regions

6 Continental Shelves Most fishing grounds are found on continental shelves for TWO reasons. 1. The shallow waters of the shelf make harvesting more cost effective. The fish have to be landed on shore for human use so the regions closer to shore are fished most profitably.

7 2. The shallow waters of the shelf promote plankton production which serve as the base of the marine food web including fish. Shallow water ensures enough light for phytoplankton and effective circulation of nutrients. See figure 12.4 on page 200. Figure 12.6, page 202 shows stocks correspond to shelves & figure 12.4 shows food web and shelves.

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14 Fisheries Management There are a number of issues related to the fishery that require management. Ocean pollution and conservation of fish stocks top the list. Major Sources of Ocean Pollution There are a number of ways to classify the greatest ocean pollution concerns. The Ocean Planet web site identifies 4 major sources of ocean pollution.

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18 The graph below, shows how many millions of gallons of oil each source puts into the oceans worldwide each year

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20 1. Oil When it comes to mixing oil and water, oceans suffer from far more than an occasional devastating spill. Disasters make headlines, but hundreds of millions of gallons of oil quietly end up in the seas every year, mostly from nonaccidental sources.

21 2. Toxic Material Industrial, agricultural, household cleaning, gardening, and automotive products regularly end up in water. About 65,000 chemicals are used commercially in the U.S. today, with about 1,000 new ones added each year. Only about 300 have been extensively tested for toxicity. TBT, or tributyltin, is added to boat paints to kill or repel barnacles and other nuisance organisms that foul ships' hulls.

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24 3. Dangerous Debris Our trash kills. When odds and ends of life on land-- particularly plastics--end up in the sea, they pose hazards to marine life. Animals drown or strangle from getting tangled in discarded or lost fishing gear, or suffer and even die from eating plastics and other garbage.

25 4. Deposits & Withdrawals For thousands of years humans have viewed oceans as vast dumps for domestic, municipal, and industrial garbage. The enormous deep-sea resources will undoubtedly attract more miners in the future, as easy-to-reach deposits on land are depleted.

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27 Mining sand from the shores of Belize for landfills in Central America. Sand and gravel are in demand as fill, and as an ingredient of concrete.

28 Impact of New Catch Technology on the Environment Factory freezer Trawlers have likely had the most significant and negative impact. 1. Highly efficient at catching fish which greatly reduces the population & reproduction. Large diesel engines, echo sounding equipment, onboard freezers, and GPS navigation contribute to their efficiency.

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30 2. Destruction of the ocean floor by trawls/draggers eliminates good spawning locations for fish. Furthermore it disperses eggs, making fertilization more difficult. 3. By-catch is often discarded. Some regulations require ships to return with low levels of by catch. 4. Traveling great distances and being able to stay at sea for long periods allows trawlers from all over the world to congregate in good fishing areas. This puts added pressure on the fish stock.

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32 Declining Fish Resource & the Livelihood of Fishers 1. Fishers may concentrate more on conservation. 2. Fishers and the community they live in will have to diversify: develop aquaculture ex. Bay D'Espoir; golf course construction ex. Frenchman s cove sea weed aquaculture ex. Isle aux Morts eco-tourism ex. Northern Peninsula catch underutilized species The declining fish resources may have a variety of affects on fishers. Some of those include:

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35 During the last half of the 20th century, the traditional view that Earth s resources are inexhaustible has been increasingly called into question (cod fishery collapse). We must, therefore, develop ways of using resources and sustaining a fishing industry for future generations. To truly understand the potential issues surrounding a sustainable fishery, students are to read pages 209 to 211.

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