NTSC-1112 Unit - 4 Oceans and Fisheries

Oceans and Fisheries

• Introduction

  • Unit - 4 focuses on oceans and fisheries.

Understanding Ocean Currents

• Ocean Surface Topography

  • Affected by waves, tides, Earth's gravitational field, and currents.

  • Satellites since 1992 have monitored sea-surface height for analyzing current patterns.

Learning Objectives

• Discuss contributions of oceans to Earth's water budget.

• Explain the impact of climate change on oceans bordering Canada.

• Describe formation of ocean currents: wind-driven and thermohaline circulation.

• Examine different stakeholder perspectives on environmental issues.

• Discuss opportunities, challenges, and significance of Northern Shipping Routes.

Key Ocean Facts

• Oceans and seas cover approximately 71% of the Earth's surface.

• Oceans regulate most of the world's weather and climate.

• Oceans produce about half of the oxygen used by humans.

Environmental Concerns Affecting Oceans

• Nutrient Pollution: Excess nutrients leading to algal blooms.

• Temperature Increase: Rising water temperatures affecting marine life.

• Ocean Acidification: Increased CO2 levels lowering pH, impacting organisms.

• Aquaculture: Sustainable practices needed to balance demand and ecosystem health.

• Overfishing: Depletion of fish stocks threatening marine biodiversity.

• General Pollution/Waste Disposal: Harmful substances affecting marine environments.

Canada's Marine Environments

• Canada is bordered by the Pacific, Atlantic, and Arctic Oceans.

• Canada has an Exclusive Economic Zone exceeding 5 million km² (7th largest globally).

• Historical use of marine environments by indigenous groups and development of fisheries.

State of the Oceans in Canada

• Reports published every four years by Oceans and Fisheries Department and Environment and Climate Change Canada.

• Focuses on the current status of Canada's three bordering oceans.

Interaction of Oceans Bordering Canada

• Currents of interest include the Subarctic Current, North Pacific Current, Labrador Current, and more.

• Coastal upwelling and downwelling influence marine productivity.

Wind-Blown Currents

• Created by prevailing winds, flowing laterally with surface currents.

• Coriolis Effect results in deflection of currents: right in the North, left in the South.

• Gyres transport heat from equator to poles.

Thermohaline Currents

• Known as the Global Conveyor Belt, characterized by:

  • Warm surface water cooling and becoming denser in polar regions.

  • Increased salinity from freezing enhances density, causing sinking into the ocean depths.

  • Process repeats slowly, with a circulation cycle lasting about 1000 years.

Climate Change Effects on Oceans

• Arctic: Significant decrease in ice cover expected, leading to increased marine traffic and pollution dispersion.

• Atlantic: Heightened storminess and potential slowing of thermohaline circulation due to freshwater influx.

• Pacific: Accelerated temperature increases (~0.25°C per decade), affecting weather patterns like El Niño and La Niña.

Canadian Oceans Activity

• Activity exploring stakeholder perspectives on fishery closures, particularly regarding snow crab to protect right whales.

Stakeholder Perspectives in Commercial Fishing

• Commercial Fisherman: Concerns about economic impacts on families and communities due to early fishery closure.

• Mi’kmaw Fisher: Looking for a fair quota under treaty rights, impact on traditional livelihoods.

• Marine Biologist: Emphasis on urgent need for conservation measures to protect endangered species.

Discussion of the Northwest Passage

• The Northwest Passage as a potential lucrative shipping route amid warming climates.

• Complications arising from territorial claims among Arctic nations.

Shipping in the North

• Northern Sea Route: Claimed by Russia while shared by Arctic countries including the US and Canada.

• Importance of navigating territorial rights as Arctic ice diminishes by 2040, opening passages.