Ocean Resource: Fish
• Oceans cover over 70 percent of Earth’s
surface.
• The global human
population eats about 145 million tones of fish each year. (2011)
• The commercial fishery provides a major food source and contributes significantly to the world economy.
Fish As A Food Source
Highlyrecommended food item due to high protein content.
Comes in a variety of forms from
processors. 1960 – 9.9
World Fish Catch By Major Source
Page 199 – Textbook
Marine capture dominates!
Information
• Fishing is a primary economic activity.
• Fishers harvest marine zoological life of varying sizes.
• There is subsistence fishing and commercial
fishing.
• Commercial is carried out in the ocean and in bodies of fresh water.
• Aquaculture involves the raising of fish and other marine life in controlled environments. A more
Location of Fish Stocks
• Fish stocks are located on continental shelves (if marine stocks).
1. Water is shallow on continental shelves.
Sunlight can penetrate to ocean floors.
Phytoplankton and zooplankton thrive and serve as sources of food for fish.
2. Water currents allow nutrients to be cycled throughout the water.
Fishing Grounds
• Page 202 - Textbook Note that major
E.g. Food Web Including Plankton
• See Textbook – Page 200
Marine Food Web
• Primary Producers (i.e. Phytoplankton)
• Primary Consumers (i.e. Zooplankton)
• Secondary Consumers (e.g. Capelin)
Fishing
• Two types of marine and/or commercial fishing include: • 1) Inshore – Involves small
owner-operated boats, 3-8 people crews, and distances from shore less than 20
kilometers. No refrigeration so they return to ports each day for fish processing at fish
plants.
• 2) Offshore – Large factory freezer trawlers that are
owned by large companies. 10 to 15 people to a boat. Can reach 350 kilometers from shore due to size and
refrigeration equipment. More capital-intensive, but less
Inshore Fishery
• Boats are small (5-10 meters). • Boats cost about $200,000.
• Boats stay near shore (~20 Km’s). • 3 or 4 people per boat.
• Boats are owned by families.
• Work is sporadic (i.e. weather and seasons). • 80 % of Atlantic fishery is inshore.
• 95 % of all Atlantic fishing boats are inshore. • Only stay out at sea for a day.
Offshore Fishery
• Boats travel great distances from the shore (~350 km’s).
• The boats can remain at sea for days or weeks. • Boats have the latest technology.
• Boats are between 20 and 50 meters in length.
• Boats and fisherpersons have their own processing equipment.
• 15 % of fisherpersons work in the offshore fishery. • Accounts for 90 % of Atlantic Canada’s fish catch. • The income is steady.
• Crews work year round.
• 15 + people can work on one boat.
Fishing
• There are two types of fish caught:
•
1) Pelagic Fish:
Congregate in schools
near the ocean surface. Examples
include: herring; anchovies; salmon;
mackerel; and tuna.
•
2) Ground Fish:
Also called demersal.
Live on or near the ocean floor.
Fishing Technology
• Early fishing involved small boats, nets (e.g. gill net), single-baited hooks and hardlines (labour-intensive), and long-lining. Fish traps were also used to catch species such as lobster and crab.
Relates to demersal fish.
• Longlines and gill nets were used to catch
pelagic fish; however, the purse-seine net was used to catch migratory fish swimming near the surface. Trolling was another approach used.
• In the 1970’s, factory freezer trawlers were used. This allowed fishers to catch more fish
and to stay on the waters for longer. Otter nets and drag nets were introduced and caused more fish to be caught.
Fish Landings
Fishing Technology
Fishing Technology
Fishing Technology
• What effects do modern fishing technology
have on the environment? (i.e. ocean
Fishing Technology
• Effects on the
environment:
• Over Fishing
• Too many fish caught.
• Less fish left to reproduce and as a result, fish species decline in
Fishing Technology
2) Damage To The Environment
• Otter nets scrape ocean bottoms destroying fish habitat and spawning grounds.
3) Water Pollution: Oil Spills and Ballast Water
• Oil spills from engines and/or motors.
• Ballast water pumped from the bottoms of
boats comprise not just of water, but gasoline, oil, and lubrications.
3) By-catch
Fishing Technology
Fishing Technology
Fishing Technology
• Question: How has modern fishing technology affected marine ecosystems?
• Consider: How does over fishing affects the marine food web?
Fishing Technology
• It disrupts marine food webs.
• If a fish species becomes extinct, the fish species that ate that species would also be
affected because they now do not have one of their sources of food. It leads to increased
competition!
Marine Pollution
• Question: What are some causes of marine pollution?
